The 'Mick Abbey' Suzuki GT-250X7
Lee's 250 @ Pembrey 2014 with the new Heron Suzuki colour scheme
Machine Overview:
We run this bike in the new post classic 250cc air cooled class, for this particular class it is an extremely competitive machine. This cracking little 250 has undergone a lot of development since Lee picked it up on eBay for a bargain price <£1000, and it has taught us a great deal along the way. With Mick Abbey now involved on the tuning side of things for this bike, it's not finished yet either! Despite being a little less than glamorous as far as a basic road machine can go, It holds a place in Lee's heart as his first race bike. More information & detail on the changes this bike has seen are captured on this page.
Machine Specification:
Engine 1 - 1979 Suzuki 250 X7 engine, Mick Abbey race tuned barrels and head. stock 26mm Mikuni carburettors, grampian re-built Suzuki crank and Mitaka Pistons, power reed valves.
Engine 2 - 1979 Suzuki 250 X7 engine, Stage 1 race tuned by Gary Teague, Stock 26mm Mikuni carburettors, PJME re-built stock Suzuki crank and new stock Suzuki pistons. Power reed valves.
Ignition - Power Dynamo TZ350 ignition.
Frame - Standard Suzuki X7 frame and swing-arm, lightened, braced and de-lugged. Also option of lengthened swingarm.
Rear Brakes - Stock Suzuki drum (cable operated).
Front Brakes - AP lockheed race caliper with GT750 master cylinder / stock Yamaha 350LC disk.
Suspension - Stock X7 forks with uprated internals, Falcon lightweight race units on rear.
Bodywork - TZ 350G seat unit, Std X7 petrol tank or Aluminium hand made Suzuki TR250 tank.
Wheels - Stock X7 rear wheel, Yamaha LC front wheel / disk.
Pipes - 'Abbeytune' race expansion chambers or Suzuki RG250 expansion chambers modified by Brian Johnson to fit the X7.
Other - Tommaselli fully adjustable clip ons, Tommaselli quick action throttle, home made rear brake controls (cable operated).
Engine 1 Output - 44 hp peak @ 9200rpm. Max revs 11,000rpm.
Engine 2 Output - 36 hp peak @ 8850rpm. Max revs 10,000rpm.
Engine 2 - 1979 Suzuki 250 X7 engine, Stage 1 race tuned by Gary Teague, Stock 26mm Mikuni carburettors, PJME re-built stock Suzuki crank and new stock Suzuki pistons. Power reed valves.
Ignition - Power Dynamo TZ350 ignition.
Frame - Standard Suzuki X7 frame and swing-arm, lightened, braced and de-lugged. Also option of lengthened swingarm.
Rear Brakes - Stock Suzuki drum (cable operated).
Front Brakes - AP lockheed race caliper with GT750 master cylinder / stock Yamaha 350LC disk.
Suspension - Stock X7 forks with uprated internals, Falcon lightweight race units on rear.
Bodywork - TZ 350G seat unit, Std X7 petrol tank or Aluminium hand made Suzuki TR250 tank.
Wheels - Stock X7 rear wheel, Yamaha LC front wheel / disk.
Pipes - 'Abbeytune' race expansion chambers or Suzuki RG250 expansion chambers modified by Brian Johnson to fit the X7.
Other - Tommaselli fully adjustable clip ons, Tommaselli quick action throttle, home made rear brake controls (cable operated).
Engine 1 Output - 44 hp peak @ 9200rpm. Max revs 11,000rpm.
Engine 2 Output - 36 hp peak @ 8850rpm. Max revs 10,000rpm.
Development
How did we manage to get a race bike from an old Suzuki X7? The X7 was actually a very popular 'clubman' racer back in the period so lends itself well to the post classic aircooled class that we run her in. The photograph below shows the bike in its 'as bought' condition. Its fair to say its undergone a few changes since then, all of which are detailed on this page. I do all my own work on the bike - including stripping / rebuilding the engine and machining my own bespoke parts, carry out the general servicing and maintenance. Tuning work is left to my sponsor Mick Abbey.
The Suzuki X7 is a 1979 model and run's AVGAS mixed with V-Power instead of just normal petrol. This has its advantages in that its a more stable fuel, with higher octane, meaning you can run higher compression and ultimately a higher state of tune.
The Suzuki X7 is a 1979 model and run's AVGAS mixed with V-Power instead of just normal petrol. This has its advantages in that its a more stable fuel, with higher octane, meaning you can run higher compression and ultimately a higher state of tune.
Set-up for Hill Climb
2012 PRE SEASON
Having discovered some Dyno print-outs amongst the many receipts that came with the bike, I decided to verify the highest reading of 32hp by going to my local 2 stroke tuner, Gary Teague. Gary ran the bike on his Dyno and we had almost as expected - 31hp, not too bad considering the bike had a claimed 28bhp when brand new and more likely 25bhp in reality. The engine revved out to approx 9500 with max horsepower @ 8600 - So basically it wasn't exactly well tuned but plenty of room to improve things. The exhaust gas reading had a slightly high CO indicating that we could have re-jetted, however - the the decision was taken to leave as is. This was due to the fact I had already entered for the 1st round with CRMC @ Pembrey and just wanted to keep the bike reliable for my first race meeting. (At this stage we were still thinking the engine had recently been rebuilt and therefore being slightly richer is safer).
I had already done a couple of track days on the bike close season and was still learning to ride the thing so not too much was going to be gained with extra power at this stage... Most important was to get the bike set-up so I could actually ride it comfortably. The foot peg positions needed changing, the gear lever position needed changing, clip-ons adjusting and the ride height raising slightly.
I had already done a couple of track days on the bike close season and was still learning to ride the thing so not too much was going to be gained with extra power at this stage... Most important was to get the bike set-up so I could actually ride it comfortably. The foot peg positions needed changing, the gear lever position needed changing, clip-ons adjusting and the ride height raising slightly.
05/01/2012 - PREP WORK:
There are a few thing that must be done to a motorcycle in order to make it eligible to race (safely). There are a few more things you can do to make it race reliably and then a raft more things that need to be done to make it race competitively!
Start of the season I faced step one - and unfortunately as you'll know if you've read my 2012 review, there was one thing I forgot before the 1st meeting at Pembrey - the 'shark fin' or chain guard. This is put in place to protect Marshall's and riders from loosing their fingers should the bike be dropped still in gear and running. This I fortunately managed to fit at Pembrey in the paddock, but ideally should be done before you turn up for scrutineering!
First thing was to fit the rather ugly fairing that came with the bike. I would have liked a nicer looking fairing for the bike, but racing on a budget means you go with what you've got so that's what I did! The fitting was a matter of drilling holes - riviting DZUS fasteners and a bit of fibre glassing to repair some old scars. I then and sprayed it flat white - fitted the green number panels and my number, 12. The fairing didn't look outstanding but would do the job and was secure enough to survive a race or 2 so I was happy.
Wire locking next - sump plug, rear brake lever locking bolt and oil filler cap. Fork drain screw sealed with some tape as no way to wire lock these and everything else torqued, bolts thread locked (Medium strength Loctite) and locking nuts used on all fasteners. I knocked up a quick plate to allow me to drop the existing foot pegs 10mm - the aim being to find a comfortable/usable position before making something more permanent. I also raised the seat height with a piece of wood between the base and the frame - again not permanent, just to give me an idea where I needed to be. I ordered up a load of spares - Main Jets for the carb a few sizes either side of the currently fitted 107.5, spare spark plugs, exhaust wadding, spare brake levers and a spare clutch perch and levers - just in case.
Some photo's below of what I started with, definitely not pretty I know but functional and got me out racing which was all I cared about!
Start of the season I faced step one - and unfortunately as you'll know if you've read my 2012 review, there was one thing I forgot before the 1st meeting at Pembrey - the 'shark fin' or chain guard. This is put in place to protect Marshall's and riders from loosing their fingers should the bike be dropped still in gear and running. This I fortunately managed to fit at Pembrey in the paddock, but ideally should be done before you turn up for scrutineering!
First thing was to fit the rather ugly fairing that came with the bike. I would have liked a nicer looking fairing for the bike, but racing on a budget means you go with what you've got so that's what I did! The fitting was a matter of drilling holes - riviting DZUS fasteners and a bit of fibre glassing to repair some old scars. I then and sprayed it flat white - fitted the green number panels and my number, 12. The fairing didn't look outstanding but would do the job and was secure enough to survive a race or 2 so I was happy.
Wire locking next - sump plug, rear brake lever locking bolt and oil filler cap. Fork drain screw sealed with some tape as no way to wire lock these and everything else torqued, bolts thread locked (Medium strength Loctite) and locking nuts used on all fasteners. I knocked up a quick plate to allow me to drop the existing foot pegs 10mm - the aim being to find a comfortable/usable position before making something more permanent. I also raised the seat height with a piece of wood between the base and the frame - again not permanent, just to give me an idea where I needed to be. I ordered up a load of spares - Main Jets for the carb a few sizes either side of the currently fitted 107.5, spare spark plugs, exhaust wadding, spare brake levers and a spare clutch perch and levers - just in case.
Some photo's below of what I started with, definitely not pretty I know but functional and got me out racing which was all I cared about!
06/04/2012 - FIRST DYNO TESTING:
After Pembrey it was noticed that the bike (and the rider admittedly) were pretty slow. I gave Gary a call and went back for a second Dyno session, 1 hour later we were up 4hp to 35hp. As noted in Dyno session 1 - the bike was set-up rich on the basis of safety (I had no idea the history of the engine so wanted to play safe on the assumption it had just been rebuilt). At Pembrey I had revved the bike so hard with no issues, so we came down from the middle to the top clip on the needle and down 1 size on the Mains to a 105. This bought the exhaust gas CO down to Gary's safe minimum for an Aircooled 2-stroke and released the extra 4hp from the engine - well happy. Its amazing how fine adjustments can make such a difference with 2 strokes! Worth noting on this point the value of Dyno sessions - as good as you may become through experience at reading spark plugs/plug chopping, my belief is the only way to be sure on base jetting settings is with a Dyno/gas analyser and a good Dyno operator. So although you inevitably may have to make small adjustments at the circuits depending on length of straights, weather conditions etc, to find the ideal start point a Dyno run is the only way as far as I'm concerned. The other benefit from the Dyno session with Gary was the extra maximum revs we gained from the engine, it now revved up to 10500 before dropping sharply off power with max horsepower @ 10000. Extra revs being just as valuable as extra hp.
2012 - IMPROVEMENTS:
The main concern at the start of the season was getting the bike comfortable for me to ride. I'm 6' 1" and the little X7 is not exactly roomy, that said - there are some big guys going really well on the little MT125's, so I am determined to engineer a solution to the size issue rather than go out and buy a bigger bike as suggested by most people! There were quite a few upgrades made over the season, these include a new front brake caliper, front wheel and disk, clip-ons, swing arm bearings, fork brace... All detailed in this section;
After Pembrey I had to quickly knock up a new foot peg hangar in time for Cadwell, this was not what i would call a 'proper job' as I didn't have the time between these 2 meetings to do it. I also quickly machined some new foot pegs with Nylon caps that would allow me to adjust them more easily than the sprung pegs currently fitted to the bike. However, although the peg positions were better at Cadwell Park- they still were not right. So before Lydden I spent quite a bit of time designing and machining properly adjustable foot peg mounts. The brake lever side was more awkward as I wanted to keep the existing lever set-up, so had to make a mount to suit.
Thankfully Lydden was the turning point for the comfort issue as I had finally got it sorted - seat raised another 1/2", new Tommaselli clip-ons set up nicely and foot pegs just where they needed to be.
After Pembrey I had to quickly knock up a new foot peg hangar in time for Cadwell, this was not what i would call a 'proper job' as I didn't have the time between these 2 meetings to do it. I also quickly machined some new foot pegs with Nylon caps that would allow me to adjust them more easily than the sprung pegs currently fitted to the bike. However, although the peg positions were better at Cadwell Park- they still were not right. So before Lydden I spent quite a bit of time designing and machining properly adjustable foot peg mounts. The brake lever side was more awkward as I wanted to keep the existing lever set-up, so had to make a mount to suit.
Thankfully Lydden was the turning point for the comfort issue as I had finally got it sorted - seat raised another 1/2", new Tommaselli clip-ons set up nicely and foot pegs just where they needed to be.
Swingarm bearings..?
Before the season had got under way I had the frame powder coated black as it was chipped and tatty in places. I removed the needle roller bearings from the swing arm before the coating and when it came to rebuilding I decided to make my own instead of refitting the needle rollers. The needle roller bearings were very expensive and In my opinion not well suited to the application. I machined some solid bronze bushes, drilled/slotted grease ways and also fitted a grease nipple to the swing arm so it could be greased after rebuilding. This made the swing arm a tighter fit to the frame and eliminated all the side to side movement that I had noticed with the needle rollers before stripping the frame down. A local firm Trestan Finishers in Woolston made a fantastic job of the frame powder coating for me and I take all my bits and pieces there for vapour blasting/coating as they are really good.
AP Lockheed front brake:
Probably the most beneficial improvement made the the bike in 2012 was the front brake. The previous owner had fitted a Honda CBR125RR caliper and master cylinder to the standard disk, and drilled the disk for cooling. Although it was no doubt greatly improved over standard - as proven at Mallory it was by no means good enough for racing. I bought a brand new AP Lockheed front caliper from Andover Norton (very helpfull people indeed) and it arrived within a week. I offered it up to the X7 disk and quickly realised it was not going to fit! I then offered it up to my Yamaha 350LC front wheel and found my solution - I needed to fit a 350LC front end to my race bike. The 350 forks are slightly further apart than the X7 giving the caliper body plenty of clearance from the spokes of the wheel - unlike the X7 wheel which didn't. I picked up an LC top and bottom yoke, and an LC front wheel from a couple of guys on the RDLC Crazy forum which I am a member of, for reasonable money. The caliper had cost me something like £160 with the pads so I was keen to keep the escalating cost down with 2 more meetings left till the end of the season!
I measured up the steering stem bearings from an LC, (old ones I had changed when I rebuilt my one) and measured up the ones removed from the X7 race bike. They were virtually the same! The old type bearings with cup and ball arrangement might have been more awkward to fit due to the depth of the recess in the frame for the bearings, but new taper roller ended up being a simple straight fit. I had kept an LC top yoke bolt, stem nut and dust guard having upgraded mine to stainless - so no expenditure there. All I had to do was buy a new taper roller bearing for and LC and fit it to the X7 frame. Once the top and bottom yokes were on the frame, the X7 forks slid into position and I now had a wider gap for the LC wheel. I had the steel bush machined to centralise the wheel as the X7 forks didn't take into account the speedo drive as the LC ones do - and the wheel was in place (new bearings and seals). All that was left to do now was make a mounting plate for the AP caliper. At this particular time I had no access to a milling machine so had to knock one up from Mild steel by hand a few days before the next meeting at Snetterton, not ideal but it did the job and now I plan to use it as a template for an alluminium replacement close season.
I measured up the steering stem bearings from an LC, (old ones I had changed when I rebuilt my one) and measured up the ones removed from the X7 race bike. They were virtually the same! The old type bearings with cup and ball arrangement might have been more awkward to fit due to the depth of the recess in the frame for the bearings, but new taper roller ended up being a simple straight fit. I had kept an LC top yoke bolt, stem nut and dust guard having upgraded mine to stainless - so no expenditure there. All I had to do was buy a new taper roller bearing for and LC and fit it to the X7 frame. Once the top and bottom yokes were on the frame, the X7 forks slid into position and I now had a wider gap for the LC wheel. I had the steel bush machined to centralise the wheel as the X7 forks didn't take into account the speedo drive as the LC ones do - and the wheel was in place (new bearings and seals). All that was left to do now was make a mounting plate for the AP caliper. At this particular time I had no access to a milling machine so had to knock one up from Mild steel by hand a few days before the next meeting at Snetterton, not ideal but it did the job and now I plan to use it as a template for an alluminium replacement close season.
The Lockheed caliper turned out to be a fantastic upgrade to the bike and improved the braking power 100% and did my confidence on it the world of good. I'm on the look out for a AP Lockheed master cylinder to match the caliper - but still getting good performance from a suitably sized Suzuki GT arrangement so when one comes along at the right price......
2013 PRE SEASON
Beautifull engineering - www.falconshockabsorbers.co.uk
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Engine ready for assembly...
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Work begins! Ok it's getting on now towards the start of the season - but I do like to set myself a challenge and getting my bike ready for the 2013 season before March is going to be no exception to that!
I have ordered all the new toys over the last week - new fairing and seat unit, new rear shocks and new ignition. The shocks are absolutely spot on, arrived yesterday and I'm really pleased with the quality of them (Photo below). The guys at Falcon are really helpful and obviously produce a quality item - they are so light! Thanks to Robin @ Falcon for his help and advice on the phone when I placed the order.
The fairing I have ordered is a TZ250 fairing and seat - as recommended by the salesman at BB plastics, expecting that to arrive by end of next week hopefully. Not decided on a paint scheme as yet - got idea's but still unsure, hoping the offer from a potential sponsor will come off so waiting on that in many ways as well.
The ignition is finally sorted - Electrex world are making a new mount plate to mount a TZ350 ignition and the TZ flywheel goes straight on matching the X7 crank taper perfectly. Will have that within a week as well, a trip up for chat with Peter @ the Electrex workshop in Oxford was well worth the journey - glad that's organised. Didn't opt for programmable in the end - want to keep things simple to start with on the new engine may change later in the season.
I have ordered all the new toys over the last week - new fairing and seat unit, new rear shocks and new ignition. The shocks are absolutely spot on, arrived yesterday and I'm really pleased with the quality of them (Photo below). The guys at Falcon are really helpful and obviously produce a quality item - they are so light! Thanks to Robin @ Falcon for his help and advice on the phone when I placed the order.
The fairing I have ordered is a TZ250 fairing and seat - as recommended by the salesman at BB plastics, expecting that to arrive by end of next week hopefully. Not decided on a paint scheme as yet - got idea's but still unsure, hoping the offer from a potential sponsor will come off so waiting on that in many ways as well.
The ignition is finally sorted - Electrex world are making a new mount plate to mount a TZ350 ignition and the TZ flywheel goes straight on matching the X7 crank taper perfectly. Will have that within a week as well, a trip up for chat with Peter @ the Electrex workshop in Oxford was well worth the journey - glad that's organised. Didn't opt for programmable in the end - want to keep things simple to start with on the new engine may change later in the season.
20/01/2013 - IN THE WORKSHOP:
Well the pre-season work is well under way now at last! Got the engine together just need to put the head on and it's ready to go in the bike. There are some photo's below showing the engine in construction - it really looks the part just hoping it goes well! I've drawn a port map of the cylinders and compared to a standard engine and also to the engine I ran last season...there's a fair few changes to note! I've decided I'm going to employ Mick Abbey, as he came strongly recommended by many, to make me a set of expansion pipes to suit the engine's tune. This is really the last bit of the puzzle as far as the engine is concerned and it would be a shame to run the Microns next season which will only hinder the engine tuning I have paid lots of money for! I am planning to run the new pipes at brands, but realistically might end up waiting till the second round unfortunately.
We have removed the old metal plate exhaust hangars / foot peg mountings that are on the standard X7 frame, and have welded on some new tubular ones. These have newly machined rubber bush mounts and look much more the part of a race bike rather than a road bike. The foot pegs will now be in fixed position (hopefully I have got them in the right place!), this saves on extra fittings on the bike which add more weight. With removing these plates, foot peg hangars and the old shock absorbers, I must have removed 3 or 4 kilo's of weight from the bike which can only be a good thing, and was great fun playing with the angle grinder chopping bits off.
I have rebuilt the forks, the right hand fork seal had gone at the last meeting last season so needed to be replaced. When I stripped the forks it was fairly obvious they had not been serviced for some time. The circlip holding the seals in place was very corroded and I had a job to get the seals out, (worst set I've ever experienced), and the oil wasn't in great shape either. While they were stripped I took the opportunity to machine the top caps (see photo), allowing simple screw adjustment of the spring pre-load in the paddock. Whether this will really work or be beneficial is yet to be seen but will be interesting to see. There's not a lot, if any of adjustment on these old forks so anything extra I can add got to be worth it.
I've also knocked up a simple foot brake lever that is a huge improvement on what I had on there last season. I have just ordered a NOS Suzuki TS250 rear brake cable which I am going to fit to the bike with this new brake lever - another significant weight saving. The frame is currently being powder coated in deep red with a pearlescent fleck, so when that is back there will be more photo's and updates to catch up on.....
We have removed the old metal plate exhaust hangars / foot peg mountings that are on the standard X7 frame, and have welded on some new tubular ones. These have newly machined rubber bush mounts and look much more the part of a race bike rather than a road bike. The foot pegs will now be in fixed position (hopefully I have got them in the right place!), this saves on extra fittings on the bike which add more weight. With removing these plates, foot peg hangars and the old shock absorbers, I must have removed 3 or 4 kilo's of weight from the bike which can only be a good thing, and was great fun playing with the angle grinder chopping bits off.
I have rebuilt the forks, the right hand fork seal had gone at the last meeting last season so needed to be replaced. When I stripped the forks it was fairly obvious they had not been serviced for some time. The circlip holding the seals in place was very corroded and I had a job to get the seals out, (worst set I've ever experienced), and the oil wasn't in great shape either. While they were stripped I took the opportunity to machine the top caps (see photo), allowing simple screw adjustment of the spring pre-load in the paddock. Whether this will really work or be beneficial is yet to be seen but will be interesting to see. There's not a lot, if any of adjustment on these old forks so anything extra I can add got to be worth it.
I've also knocked up a simple foot brake lever that is a huge improvement on what I had on there last season. I have just ordered a NOS Suzuki TS250 rear brake cable which I am going to fit to the bike with this new brake lever - another significant weight saving. The frame is currently being powder coated in deep red with a pearlescent fleck, so when that is back there will be more photo's and updates to catch up on.....
28/02/2013 - FINAL ASSEMBLY:
As you can see from some of the above photographs, the final assembly of all the re-worked parts is under way. The season fast approaches in 3 weeks time, and things are coming together nicely. I had a custom baseplate machined for the ignition, Electrex could not make me one in time for the season start so I had the basic plate and slot machined and then made the final adjustments on the lathe. Below are some photo's of the assembly process, the red powder coating has a great metallic finish that shows in the sunshine, will look nice if we get any sun this season! I'm in the process of trying to get a logo designed so that I can get some decals made up for the fairing, my race helmet and also the van - it will be nice to have something personalised on the bike paintwork.
2014 PRE SEASON
Cracking weekend @ Donnington Park
After a fantastic 2013 season on the 250 Suzuki, we are making plans for the 2014 season nice and early. Improved prospects of an Aircooled 250cc class, or at least a 250cc sub class looking better for next year gives us 250 lads something more to focus on.
As you will have seen on the sponsors page - Mick Abbey has very kindly offered his services for next year - so the little 250cc Suzuki motor will be spinning even harder with Mick's tuning and a set of expansion pipes to match. While Mick has the bike to carry out the work, I have set about getting another bottom end all up together so that I'll have 2 engines available to drop in next year. A freshly rebuilt (Grampian Motors) crank is going into a very good set of casings that I have had vapour blasted, fitted with decent gearbox and all new seals. This bottom end will be the one that Mick's tuned cylinders will be bolted onto for race 1 at Pembrey next year. The motor I used last year is still in good shape so that will be my fall back spare if we have any issue's. Below I have some before and after vapour blasting photo's and some photo's of the bottom end being rebuilt.
As you will have seen on the sponsors page - Mick Abbey has very kindly offered his services for next year - so the little 250cc Suzuki motor will be spinning even harder with Mick's tuning and a set of expansion pipes to match. While Mick has the bike to carry out the work, I have set about getting another bottom end all up together so that I'll have 2 engines available to drop in next year. A freshly rebuilt (Grampian Motors) crank is going into a very good set of casings that I have had vapour blasted, fitted with decent gearbox and all new seals. This bottom end will be the one that Mick's tuned cylinders will be bolted onto for race 1 at Pembrey next year. The motor I used last year is still in good shape so that will be my fall back spare if we have any issue's. Below I have some before and after vapour blasting photo's and some photo's of the bottom end being rebuilt.
Before Vapour
After Vapour
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After Vapour
Grampian rebuilt crank
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23/12/2013 - MICK ABBEY TUNING:
The Abbeytune pipes and Mick Abbey tune that has been carried out on Mike's RD250 has transformed the little Yamaha performance wise. I had taken the X7 up to Mick's with me when we collected the RD250 as Mick is currently running in his new Dyno and wanted to compare some old figures I have for my bike versus his Dyno readings. When we ran the X7 on Mick's dyno, I was pretty disappointed to find that the figures I had from previous Dyno work were pretty optimistic. Having said that I think It's always important to remember that dyno figures don't really mean a great deal, its the difference from where you start to where you end up (on the same machine) and the shape of the power curve that counts. Dyno output figures can vary heavily among differing machines as we all know, but the power curve should read the same from machine to machine. Mick's dyno is set-up to read slightly lower (1.3%) than some of the more main-steam Dyno machine's such as Dynapro, this is done intentionally so as to not over impress with inflated figures - which I think makes sense.
Taking into account the dyno figures that we found and the fact I managed some decent lap times on what appeared to be an underpowered machine last year, Mick offered to do the tuning work to give me more power and estimated in the region of 45hp (on his dyno) as an easily achievable peak figure for the little 250. This would really help me push on, especially if a 250cc subclass start's within the CRMC AC500 class as we expect it may. The aim was to increase peak hp and increase the peak rev's slightly, without loosing too much lower to mid range hp. It's inevitable that some low-range hp will be lost as the cylinders are re-worked for increased peak power, but this loss can be limited and that's how Mick planned to go with my bike. Mick's dyno print-out's are shown below;
Taking into account the dyno figures that we found and the fact I managed some decent lap times on what appeared to be an underpowered machine last year, Mick offered to do the tuning work to give me more power and estimated in the region of 45hp (on his dyno) as an easily achievable peak figure for the little 250. This would really help me push on, especially if a 250cc subclass start's within the CRMC AC500 class as we expect it may. The aim was to increase peak hp and increase the peak rev's slightly, without loosing too much lower to mid range hp. It's inevitable that some low-range hp will be lost as the cylinders are re-worked for increased peak power, but this loss can be limited and that's how Mick planned to go with my bike. Mick's dyno print-out's are shown below;
Dyno 1 - 250 X7 cylinders as run for the 2013 season with RG 250 pipes
Dyno 3 - 250 X7 Mick Abbey ported cylinders with Abbeytune pipes
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Dyno 2 -250 X7 cylinders as run from 2013 season with Abbeytune pipes
Dyno 2 vs Dyno 3 - Comparison of the two sets of cylinders
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So taking into account the jetting that I need to look at, although the X7's new power curve is massively improved from last year, there is potentially still a little more to come... If you look at the new curve on Dyno 3, up until 6000rpm the jetting was poor and the engine was not revving freely, spluttering and holding back. The air/fuel meter was telling us it was lean although the way it was behaving pointed to rich running. We lifted the needle's (to be on the safe side) as a test and the problem got worse, so definitely suspect it to be too rich. Apparently the wideband A/F meter can read high (false) if the exhaust gas is extremely rich, however due to time limitations we couldn't keep doing run's to get to the bottom of the issue. In the new year I'll be taking the bike to a local dyno just to finalise the jetting ready for the season, and also feed back to Mick on his dyno reading accuracy. Based on what we were seeing on the day, the plan is to increase Pilot size (to aid starting) by at least one increment and then to drop the needle right down and adjust from there on the dyno.
This minor issue doesn't take away from the huge improvements that have been made. The Abbeytune pipes instantly unleashed another 1000rpm from last years cylinders, holding onto good power instead of dropping away @ 9000rpm. Then we saw a jump of 6hp @ peak rev's with only a minor loss of mid-range power with Mick's ported cylinders. As expected there is a loss of low range power sub 6000rpm, by the time the rev's reach 7000rpm there is only a 2hp drop, and then once the new motor reaches 7500rpm Mick's porting comes into it's own and the pulls towards 40hp holding onto it until 10250rpm. To put it in perspective - my motor from last year @ 9000rpm was pulling 28hp but falling away fast, my new Abbeytune pipes and Mick Abbey ported engine @ 9000rpm is holding 40hp and climbing. No doubt this is going to be a very different bike to ride from last season, but it gives the X7 more edge in terms of performance and it will just be down to me to ensure I keep the bike spinning above 7000rpm all the way round the circuits! I have linked some video's of the Dyno runs on that are on my Youtube channel.
This minor issue doesn't take away from the huge improvements that have been made. The Abbeytune pipes instantly unleashed another 1000rpm from last years cylinders, holding onto good power instead of dropping away @ 9000rpm. Then we saw a jump of 6hp @ peak rev's with only a minor loss of mid-range power with Mick's ported cylinders. As expected there is a loss of low range power sub 6000rpm, by the time the rev's reach 7000rpm there is only a 2hp drop, and then once the new motor reaches 7500rpm Mick's porting comes into it's own and the pulls towards 40hp holding onto it until 10250rpm. To put it in perspective - my motor from last year @ 9000rpm was pulling 28hp but falling away fast, my new Abbeytune pipes and Mick Abbey ported engine @ 9000rpm is holding 40hp and climbing. No doubt this is going to be a very different bike to ride from last season, but it gives the X7 more edge in terms of performance and it will just be down to me to ensure I keep the bike spinning above 7000rpm all the way round the circuits! I have linked some video's of the Dyno runs on that are on my Youtube channel.
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Now I have got the bike back I will be removing the engine, taking the Mick Abbey tuned top end off to go onto the freshly rebuilt bottom end that I have built up. There will be some more photographs of the rebuild to follow. Last years top end can go back onto last years bottom end as a spare engine for 2014. The RG250 pipes I shall be keeping as decent usable spares.
Last thing to say on this update is huge thanks to Mick Abbey - top bloke to work with a definitely comes recommended for his tuning work and pipes. As you can see from the photo's and video - the pipes look quality and do the tuning justice as well. Cheers Mick.
Last thing to say on this update is huge thanks to Mick Abbey - top bloke to work with a definitely comes recommended for his tuning work and pipes. As you can see from the photo's and video - the pipes look quality and do the tuning justice as well. Cheers Mick.
10/01/2014 - THE X7'S NEW FRAME:
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At some point during the 2013 season the poor X7 has taken one hell of a smack. The front end of the bike is no longer in line with the back end, to the point where you don't need a straight edge to see it, it's visible just to look at! Considering the flimsy nature of the X7's frame (but nice and lightweight), I'm not too surprised this has happened. It's hit the tarmac no less than 5 times since I've been racing and the high speed off at Cadwell Park in 2013 I think was the one that done the damage.
The photograph above shows the spare frame I have had hidden in the rafters of my workshop 'just in case', its already been de-lugged in the photo but further work is needed to clean it up totally. The photo's below show the work involved in getting this new frame ready for the modifications..... |
The spare X7 frame before I took to it with a grinder
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Approx 2.5kg's of brackets removed.
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Around 3 hours work just to de-lug and grind back
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Ready for new brackets, mounts and bracing
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While we have the frame in this state - there are some improvement's that I would like to make versus the frame I have been using for the last 2 years. This includes the following items;
- Some extra bracing to help stiffen things up in area's that I know are flexing excessively.
- New mudguard mounting points with anti vibration fittings.
- New foot peg mounts vs the old frame.
- Under seat 'loop' and new seat mountings
- New Scitsu and fairing headstock mount bracket.
- Steering damper bracket mounting.
Here are some photo's of all the mods that we have made to the frame (click to make them bigger);
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14/02/2014 - IDENTITY CRISIS:
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I have decided that the X7 currently suffers from a sevre lack of identity which is entirely my doing through the changes I have made to it. The aluminium T20 tank and the TZ fairing & seat are a mish-mash of different period parts that take away from the original Suzuki X7 image - essentially it looks a bit like a classic but not really!
To this end I am going to use the standard petrol tank instead of my T20 tank, I am also going to fit a different TZ seat unit and probably run the bike naked next season with no fairing - much like they were raced in the period. My inspiration came from the photo shown on the right, which I saw on Facebook on the 'keep 2strokes alive' group timeline. I am going to run the bodywork with the period Heron Suzuki colours of red/black with yellow and white detailing. |
The X7 makes a lovely looking clubman racer
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24/03/2014 - GETTING IT TOGETHER:
It's been a while since I have updated the status of the bike - so just a brief update on things with the little Suzuki.... I have been hard at work in the garage every spare moment getting the bike back together - making little improvements where needed on the way. New mounting lugs and brackets on the new frame, new rear brake assembly with rear sets and the TZ seat unit are all coming together and the X7 is slowly starting to look like a well prepped racer again. I have lots of photo's that I have taken to illustrate some of the changes that have been made - considerable time has been spent on the lathe and milling machine to fabricate the little bits and pieces which obviously all takes time. I'm aiming to have the bike on the Dyno next week, so that I can get a initial set-up sorted before the season starts but its unlikely I'll be using the bike in anger until the first practice at Pembrey. Better make sure its all up together!
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I guess its fair to say that things have been sort of a rush over the last few weeks, which is by no means my favourite way to go. But having said that we have taken our time with the frame to make sure its right and have also been let down by some surprises along the way. The most shocking being the damage to the spare frame that I had not previously noticed on the head stock. As you can see in the photo's below, a previous owner of this frame decided to grind out the headstock bearing boss to fit a larger diameter puter race, leaving the headstock worryingly thin. The only option was to re-machine a new headstock boss, cut the old on off and re-weld the new one in place. It's all a good job now but that was an un-expected surprise that we could have done without!
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So the next post you should be reading on this X7 section of our 'development' page should include photo's of the fully built bike, all ready to race. I'll be putting the details of the Dyno session up when I get them, and also got the bodywork to sort once Ive decided a colour scheme to race with this year, so they'll be some pics of that too once finished. Lets hope I'm not taking those 'finally built & ready' photos on the night before the first meeting at Pembrey!
12/04/2014 - READY FOR RACING:
So the X7 is all finished (nearly all)! We went for the Heron Suzuki paint scheme which has come out really well and I'm really pleased with it. Not bad for a DIY job in my Dad's garage! I've got a plan to fit a faring eventually and have the full Heron Colour scheme but that can be done later on and is not essential for the first meeting. There are a few minot jobs left to finish but can wait till after the first meeting.. There are several small bits like brackets etc that need powder coating. I have fabricated a pretty simple Scitsu mount bracket that does the job nicely and keeps the bike looking tidy behind the number board. When we get back from Pembrey I'll whip the few bits off the bike and get them down to our local coaters to finish the job.
So really now it all comes down to track set-up and actually riding the thing which feels like such a long time ago! Im really looking forward to getting out on the track and seeing what the new motor goes like with the Abbeytune cylinders and pipes. Ive spent an hour on a Dyno, which was all slightly last minute really but it allowed me to put some run in miles on the crank and ensure that I'll make it through Pembrey without any nipping up the new pistons to the bores.
The Dyno time threw up some useful but also confusing information, as usual the A/F readings didn't quite add up (very rich in places as witnessed from various plug chops), yet a very lean reading on the scale. It was also pulling very well at times and not at others, pointing to some jetting issues that unfortunately we couldn't get to the bottom of due to lack of time (left the Dyno machine a 9pm!). But at least we had an idea where to start at the Pembrey test day. As we were still really running the crank in - the Dyno operator didn't want to rev on too hard, so the runs stopped just over 9000rpm. However we did rev it on once or twice and were seeing 10,750rpm without a fall off in power, so there's much more to be had out of this engine yet. I've added a scan of the Dyno print-out below,
So really now it all comes down to track set-up and actually riding the thing which feels like such a long time ago! Im really looking forward to getting out on the track and seeing what the new motor goes like with the Abbeytune cylinders and pipes. Ive spent an hour on a Dyno, which was all slightly last minute really but it allowed me to put some run in miles on the crank and ensure that I'll make it through Pembrey without any nipping up the new pistons to the bores.
The Dyno time threw up some useful but also confusing information, as usual the A/F readings didn't quite add up (very rich in places as witnessed from various plug chops), yet a very lean reading on the scale. It was also pulling very well at times and not at others, pointing to some jetting issues that unfortunately we couldn't get to the bottom of due to lack of time (left the Dyno machine a 9pm!). But at least we had an idea where to start at the Pembrey test day. As we were still really running the crank in - the Dyno operator didn't want to rev on too hard, so the runs stopped just over 9000rpm. However we did rev it on once or twice and were seeing 10,750rpm without a fall off in power, so there's much more to be had out of this engine yet. I've added a scan of the Dyno print-out below,
Mick was happy as these few runs proved up the relative accuracy of his Dyno machine pretty well. The Air/fuel reading was starting to look somewhere more sensible towards max RPM, this is where I would opt to run slightly richer anyway to help keep the engine cool. On the subject of temperature, I have picked up a couple of spark plug temp (CHT) sensors to use while out on the track, this will help me to understand how the bike is performing and also help prevent any heat seizures if the engine starts to run too hot. The up and down on the readings shown on the chart early in the RPM's is where we need to get sorted, as this will affect performance on the circuit. As always getting a set-up takes time and a lot of thinking about, the only real way to see the results is on the circuit. Pembrey here we come!
Bit of imaginative engineering...
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Both bikes oiled / fuelled / wire locked & ready to roll
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2015 PRE-SEASON
So what are the plans for 2015? Well we are more than happy with the power the motor is making, however we are less happy with the way the bike is handling. Towards the tail end of last year having suffered a few 'off's' I started to pay more attention on how the bike was handling and trying to understand how to make it better. You would think this to be straightforward, but with no suspension expert to hand and limited adjustment available on the Suzuki, its going to take some thinking about, set-up understanding and some mods. The planned changes are listed below;
There are a few other jobs that I intend to do, that will include a new ignition, new fuel supply taps on the petrol tank, replace damaged exhaust pipe and change the pistons/rings/small ends, when I crashed the bike at Cadwell and did a fair bit of damage to the exhaust and sheared off the steering stops, so repairs over the winter are essential.
- Lengthen the swingarm to improve stability of the bike at high speed.
- Fit lighter wheels - spoked with Alluminium rims & rear disk brake to save weight.
- Change the fork Oil for a heavier grade
There are a few other jobs that I intend to do, that will include a new ignition, new fuel supply taps on the petrol tank, replace damaged exhaust pipe and change the pistons/rings/small ends, when I crashed the bike at Cadwell and did a fair bit of damage to the exhaust and sheared off the steering stops, so repairs over the winter are essential.
15/01/2015 - NEW YEAR UPDATE:
So we are getting somewhere.... slowly!! Having left the bike out in the shed for several months after last season, it is now in full pre-season prep mode;
Having sacrificed my 6x6 meter garage/workshop last year to move into a bigger house I'm now overhauling 2 race bikes at the back of my Dad's garage until my new Shed is built which wont be till summer... However, none of this will stand in the way of getting the bikes ready!
There are a number of 'fiddly' jobs that I'd like to get finished before the the start of the season, but none of which are 100% essential to get us going so at the moment its a case of work through the list and see where we end up.
On the subject of the more serious stuff that needed to be done - Colin Western has pointed me in the direction of Power Dynamo ignitions, having suffered some reliability issues with my Electrex world kit last year (which is now boxed as a last gasp spare). Colin very kindly machined a nice back plate for me as my lathe is not big enough to do big jobs like that being a model makers machine. All I had to do was spot though the hole's, machine some slots for screw heads and the turn down the back of the plate to ensure the rotor was positioned correctly. This sounds like a work up but wasn't too bad in the end. I have also had the cylinder heads and barrels spigoted to get away from having to use gaskets, and also allowing me to run a permanently fixed squish gap of 0.85mm. This will reduce paddock rebuilding hassle no end. The final job I have been working on is the fuel supply from the stock Suzuki tank. The Suzuki tank has no balance tube connecting the two sides of the tank body. Last year I had no end of fuel supply issues that cost me several races, most noticeable at hilly circuits such and Brands / Donnington and Cadwell. So it was time to machine 2 x 1/4BSP boss's, braze them to the bottom of the tank and fit 2x 1/4BSP hi flow ball valves, that should get rid of the fuel supply problem....
There are a number of 'fiddly' jobs that I'd like to get finished before the the start of the season, but none of which are 100% essential to get us going so at the moment its a case of work through the list and see where we end up.
On the subject of the more serious stuff that needed to be done - Colin Western has pointed me in the direction of Power Dynamo ignitions, having suffered some reliability issues with my Electrex world kit last year (which is now boxed as a last gasp spare). Colin very kindly machined a nice back plate for me as my lathe is not big enough to do big jobs like that being a model makers machine. All I had to do was spot though the hole's, machine some slots for screw heads and the turn down the back of the plate to ensure the rotor was positioned correctly. This sounds like a work up but wasn't too bad in the end. I have also had the cylinder heads and barrels spigoted to get away from having to use gaskets, and also allowing me to run a permanently fixed squish gap of 0.85mm. This will reduce paddock rebuilding hassle no end. The final job I have been working on is the fuel supply from the stock Suzuki tank. The Suzuki tank has no balance tube connecting the two sides of the tank body. Last year I had no end of fuel supply issues that cost me several races, most noticeable at hilly circuits such and Brands / Donnington and Cadwell. So it was time to machine 2 x 1/4BSP boss's, braze them to the bottom of the tank and fit 2x 1/4BSP hi flow ball valves, that should get rid of the fuel supply problem....
Heads/cylinder spigoted
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New power dynamo ignition
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Clocking in Colin's back plate
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1/4 BSP hi-flow ball valves
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29/01/2015 - BACK UP TO MICK ABBEY:
So with the new ignition fitted and timed up, the cylinders/heads spigoted and the fuel taps sorted it was time to head back up to Mick Abbeys workshop. Mick will be supporting me again in 2015, which I am really pleased with. The X7 last year was one of the quickest bikes out there if not the quickest, with these few reliability issues sorted I'll be hoping to push the 2015 championship even harder. Mick will be sorting me with a replacement exhaust pipe (Apologies for wrecking last seasons set Mick) and also re-machining my cylinder heads to ensure that the compression is correctly set as per his tune last year. (Removing material from the head for the spigot will have pushed the compression up far too high for sure).
I set off to Mick's with Keith Howard and his little RD250. Keith is the newest 250AC novice and will be racing under our banner in 2015, so there will be some photo's and details of his bike to follow. The intention for the day was to re-machine the heads on my X7, then run it up on the Dyno to test the new ignition. We would also be running up Keiths RD250 on the Dyno to give Mick a start point, as he will be porting the barrels and making pipes for the bike. It took a little longer to get the X7 going than we had hoped as the heads required a lot of machining, but once it was up and running it went like a train making just over 42hp with a dented/bent exhaust pipe. The fresh motor/pipes with the old ignition had made 44hp on Mick's dyno last time out, so we were happy with the figure. Once Mick has made the new pipe I will be travelling back up with Keith for a final set-up on the Dyno, I intend to try tweaking the ignition advance slightly to see if there's a bit more to squeeze from the motor as well.
Keith's RD250 also stayed with Mick for the Abbeytune treatment - if my Dad's bike last year is anything to go by Keith is going to have a fierce introduction to 250cc racing! Thanks to Mick for a good day - we left the house at 05:00 and didn't get home till 00:30 the following day, it was very tiring but certainly worth it getting to play with our 2-Strokes all day!
I set off to Mick's with Keith Howard and his little RD250. Keith is the newest 250AC novice and will be racing under our banner in 2015, so there will be some photo's and details of his bike to follow. The intention for the day was to re-machine the heads on my X7, then run it up on the Dyno to test the new ignition. We would also be running up Keiths RD250 on the Dyno to give Mick a start point, as he will be porting the barrels and making pipes for the bike. It took a little longer to get the X7 going than we had hoped as the heads required a lot of machining, but once it was up and running it went like a train making just over 42hp with a dented/bent exhaust pipe. The fresh motor/pipes with the old ignition had made 44hp on Mick's dyno last time out, so we were happy with the figure. Once Mick has made the new pipe I will be travelling back up with Keith for a final set-up on the Dyno, I intend to try tweaking the ignition advance slightly to see if there's a bit more to squeeze from the motor as well.
Keith's RD250 also stayed with Mick for the Abbeytune treatment - if my Dad's bike last year is anything to go by Keith is going to have a fierce introduction to 250cc racing! Thanks to Mick for a good day - we left the house at 05:00 and didn't get home till 00:30 the following day, it was very tiring but certainly worth it getting to play with our 2-Strokes all day!
10/04/2015 - POST PEMBREY:
We cut things a little fine in preparation for the 1st meeting of the year at Pembrey, but we got there just about. Having taken the X7 and Keiths RD250 up to Mick's for repairs and tuning work respectively - very pleasingly on our return from the 'Mick Abbey emporium of speed' - the graph below is what we bought back with us;
Keith was dead pleased with his new engine and I was equally impresses that my X7 was still putting up good power with an engine that was 1 season old and now running nicely with the repaired exhaust pipe. Clearly Keith's bike packs a lot more punch than the Suzuki over 9250rpm - so I went to Pembrey apprehensive about how competitive the X7 might be up against these new RD250 rocket ships....
For me Pembrey was a very satisfying weekend from a reliability perspective - the X7 ran perfectly in all the races, as did the Harris 350. We never actually got round to fitting the lengthened swing arm as planned nor did we change the pistons/rings before Pembrey. As I said above we were thinking that the RD250's may be too much for the X7 so held off on changes in-case we might need another bike, but having seen X7's still dominating the class all weekend at Pembrey we are glad to be sticking with the Suzuki. New pistons will be going in with rings and small ends, and I am in the process of machining bushes for the new swing arm. I am also sending off my spare crank to Grampion for rebuild and another set of barrels up to Mick to tune so that we can carry a spare built motor ready to chuck in should it be needed. (Hopefully not but who know's).
The new swingarm is slightly longer than the X7 by approx 20mm, the idea is that it will make the bike more stable in fast corners. Hopefully it wont detract from the nimble nature of the X7 which gives it the edge handling wise in the 250 class. This will be fitted for the trip to Cadwell as a trial but the X7 swing arm is available to go straight back in if we don't think there is any benefit to the longer arm. There are afew other fiddly bits to sort, new clutch cable needed to suit the new lever that I fitted at Pembrey and we need to re-do the paint on the seat as its not as tidy as we'd like. There will be some photo's of the swing arm mods coming soon.....
For me Pembrey was a very satisfying weekend from a reliability perspective - the X7 ran perfectly in all the races, as did the Harris 350. We never actually got round to fitting the lengthened swing arm as planned nor did we change the pistons/rings before Pembrey. As I said above we were thinking that the RD250's may be too much for the X7 so held off on changes in-case we might need another bike, but having seen X7's still dominating the class all weekend at Pembrey we are glad to be sticking with the Suzuki. New pistons will be going in with rings and small ends, and I am in the process of machining bushes for the new swing arm. I am also sending off my spare crank to Grampion for rebuild and another set of barrels up to Mick to tune so that we can carry a spare built motor ready to chuck in should it be needed. (Hopefully not but who know's).
The new swingarm is slightly longer than the X7 by approx 20mm, the idea is that it will make the bike more stable in fast corners. Hopefully it wont detract from the nimble nature of the X7 which gives it the edge handling wise in the 250 class. This will be fitted for the trip to Cadwell as a trial but the X7 swing arm is available to go straight back in if we don't think there is any benefit to the longer arm. There are afew other fiddly bits to sort, new clutch cable needed to suit the new lever that I fitted at Pembrey and we need to re-do the paint on the seat as its not as tidy as we'd like. There will be some photo's of the swing arm mods coming soon.....
18/05/2015 - SEASON SO FAR:
So apart from a blowing head gasket at Cadwell Park - due to no longer having a compressed head gasket, the reliability issue's I suffered last year seem to be pretty much resolved. I put that mainly down to the twin hi-flow ball valve fuel cocks that I have fitted to the tank, eliminating the fuel supply problem that got us several times last year.
The other main change Ive made is the bit I want to expand on now - the Power dynamo ignition. I had wanted to change the ignition ready for 2015 despite the fact the previous electrex ignition was tested and proven functional. Colin Western had been raving about the simplicity and quality of the power dynamo kit that he runs on his RD. He talked me into fitting one on the X7, even offering to machine me a back plate as power dynamo don't currently offer one as a stock part. I ordered the basic kit with a TZ rotor (TZ & X7 crank tapers are the same), and Colin did the bulk of the machining for the back-plate (my lathe was not big enough to take the billet). All I had to do was machine some recesses for the Allen bolt heads, spot through from the existing X7 back-plate for the mounting holes and then machine the rear of the back-plate down to ensure the rotor was exactly 5mm inside the outer stator. Simple!
The other main change Ive made is the bit I want to expand on now - the Power dynamo ignition. I had wanted to change the ignition ready for 2015 despite the fact the previous electrex ignition was tested and proven functional. Colin Western had been raving about the simplicity and quality of the power dynamo kit that he runs on his RD. He talked me into fitting one on the X7, even offering to machine me a back plate as power dynamo don't currently offer one as a stock part. I ordered the basic kit with a TZ rotor (TZ & X7 crank tapers are the same), and Colin did the bulk of the machining for the back-plate (my lathe was not big enough to take the billet). All I had to do was machine some recesses for the Allen bolt heads, spot through from the existing X7 back-plate for the mounting holes and then machine the rear of the back-plate down to ensure the rotor was exactly 5mm inside the outer stator. Simple!
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Seriously this is a great bit of kit - I would strongly recommend it to anyone who wants a quality 'fit and forget' ignition that does the job nicely. There are minimal electrical connections which reduce the chance of breakdown problems, and the stator and the CDI unit itself are really well made. They are also extremely good value in terms of price compared to some of the stuff out there..... To order one of these kits just click on one of the above photo's and it will take you straight to their online shop. They also have a really good technical assistance system whereby you can email the experts with your questions and he will get back to you with helpful answers. For info the kit I have here is a basic race ignition with a TZ/RD rotor.
Next in for the X7 is a crank rebuild, up-rated progressive fork springs (to try a affect the chattering issue's I'm having) and bigger carburetors... Watch this space more to follow over the next week.
Next in for the X7 is a crank rebuild, up-rated progressive fork springs (to try a affect the chattering issue's I'm having) and bigger carburetors... Watch this space more to follow over the next week.
Any questions or comments?
If you have questions about any of our bikes - be it specification / eligibility / spares / tuning, please feel free to drop me an email I will try to get back to you ASAP with answers. Have a look at the development page for further info on the hard work that goes into these bikes behind the scenes in preparation for race meetings.
Useful information / reference files:
| mikuni_basic_carb_theory.docx |
| mikuni_jet_flowrates.docx |
| mikuni_needle_listing.xls |
| classic_bike_2006_-_x7_info.pdf |
