We have the software and hardware capability’s available which allows us to make changes to fuel maps, ignition maps, rpm limiters, secondary throttle maps, as well as many other maps and setting in your Suzuki, Kawasaki, Yamaha, KTM, Aprilia and Triumph. The software works with USB interface and allows flash changes to the ecu of your motorcycle. Get rid of those restrictions and enjoy the full potential of your bikes engine!
We can also make and fit decat link pipes for bikes fitted with a catalytic converter to not only increase the horse power available but also lighten the bike by a reasonable amount. One recent bike was a GSX1000S which we made a pipe for and flashed the ECU, gaining 15bhp in the midrange and 14bhp top end and also save about 8kg weight. It also improved the look of the bike and Clive, the owner, was very pleased with the results and said “I can’t say how much better it is and great service by Cambridge motorcycles can’t recommend them highly enough”.
Another recent one was a GSXR750 which had a power gain of about 10 bhp and again a weight saving of around 8 kg after we made and fit the decat pipe and flashed the ECU, customer said it was a completely different bike on track and was over the moon with it.
My name is David Abraham better known as ‘Spike’ to my friends. I’ve been a part of Cambridge Motorcycles for the past 28 years.what started as an all consuming hobby when I was sixteen,turned into a way of life at the age of twenty five .I consider myself very fortunate to have been able to indulge my passion for all sorts of bikes and even at the age of 50 the fun ain ‘t over yet. I have a lot of bike related history,british ,american,japanese and lately italian.My knowledge of bikes has been hard won by practical experience,from building choppers in the garden shed ,to 7 second dragbikes and so far one championship winning four hundred supersport. I am lucky enough to have my own dynojet dynomometer,which is kind of handy when you want to prove your own tuning theories.
My involvement with circuit racing all started 15 years ago , when I met a new customer and friend called simon morley.He was just starting his racing carrier having spent years riding sports bikes and cruisers on the road. He’d started on track days ,got the bug and bought a ZX6R to race .Unfortunately he took it to a bike shop to get it prepared and while trying to sort the wiring loom they stripped it back and couldn’t figure out why the bike wouldn’t run.This caused him to loose faith in they’re abilities and I gained a good customer and friend in the process.
While I was sorting his bike out simon suggested coming on a track day with his mates at team ixion( T.IXION is an internet bike racers / riders site ,run by a lot of helpful friendly types,good for advice if you are thinking of track days or racing). The track day did it for me,at the ripe old age of forty , I thought I was quite a good all round rider and a bit handy round the bends when I needed to be. Well it was a real eye opener . I went out in the slow group on what turned out to be my evil handling TL1000R . James Denning (another TI member and all round good guy) said he would give me some instruction and show me the way around Cadwell park a very demanding circuit. He hung cooley of the side of his bike while waving encouragement while I sweated and struggled to keep up. What I learn ‘t on this day was vast , how to approach a corner , how hard you could really brake when you have to , just how sticky modern tyres are and what an evil handling beast my streetfightered TL really was . I persevered with the TL for a few more track days , but after some nasty moments decided it was high time for something better .
I had been doing some work for a customer and as payment he offered me an old 1988 FZR400 , it was stripped to the bare bones , but made an ideal first track day bike . I can’t describe the satisfaction you get from blowing away people on high power sports bikes on it . Now out the back of the workshop was a 1992 ZXR400L which had a lump missing from the frame where it had been crashed written off and abandoned by the insurance company . Now these little bikes might not be the fastest thing on the block but they sure do handle even with stock suspension . It was about this time I decided to I’d had enough of dragracing. I’d had a fair bit of success over five years of racing .I came second (first loser)in the UK ACU Funny bike champs after a points debacle . Competed in a few euro rounds and won some money.This is were my engine tuning experience came from (turbo’s,nitrous oxide and high octane fuel) , so I Thought why not apply this experience to tuning circuit race bikes , that’s how ZXR400 race bike project got going . I bought some race plastics for it , fitted race exhaust can ( luckily it already had titanium down pipes) , race rev counter and generally stripped off unleaded items . I did a few track days on it and thought it would make a great race bike .
It was at the end of 2000 that Martin Wright a riding instructor and rookie 600 super sports rider suggested I might let him race it in the British motorcycle racing club’s 400 super sport championship 2001 . My abilities as a rider were not up to race pace as yet , but I’d started to do some tuning work to the engine , so I thought this would be a good way to find out if I had what it took to be a circuit bike tuner . so we headed into 2001 full of expectation . Our agreement being I provide the bike and Martin paid the race entry fee’s & tyre bill . Our season together had plenty of up’s & downs . Martin not known to mince words , was not very complimentary about the handling , but this was a whole new ball park for me and we set to work putting it right . Fitting an ohlins shock and changing fork springs and oil . Now suspension is a black art with some right old bollocks flying about , but we found our way through the minefield by a lot of trial & error , our main constraint was budget . As the season progressed we came on in leaps & bounds . I had tuned the engine to the point where it was almost the fastest bike out there ( very reliable as well , same motor whole season). Martin had gone from being 8/10th to winning races & coming 4th in the championship . So we figured we did well for our first attempt .
While this was going on I did more & more practice met lots more racers & generally got caught by the bug . Now having watched all the classes race,the 400/600 supersport were by far the most aggressive ( full of young dumb and full of come) . So I thought this is no place for a 40 year old irresponsible father , so I went for Supertwins , where there’s a bit less paint trading . Having realised my TL1000 was never going to handle properly , I bought myself an Aprilia RSVR for the road ( one of the best handling out the crate bikes ever all for 8.5k) . It was another total revelation , you could tell it was a corner hungry beastie the moment it moved and a few track days at mallory told me you’ve got to race this . I set about preparing the bike,but didn’t tune the engine as I didn’t want to affect it’s reliability and figured I’d be better off figuring out suspension & tyres first . Due to the price of Aprilia parts I found some suzuki 750 s/rad wheels to modify to put intermediate & wet tyres on . As I’d got a good deal with Michelin I decided to run they’re tyres , despite a lot of people telling me they gave no warning when they were going to let go ( they were right and still holds true) .Very hard to get them upto temperature in the cold UK climate .
Meanwhile Martin was lured away from riding the ZXR400 by offers of greater things . So I asked some T.Ixion members for riding suggestion’s and the general consensus was a lad called Chris Foster ( better known as Fozzy ) . So a phone call later and he agreed to give it a go . Unfortunately he’d been feeling under the weather for a while and had just found out he had kidney failure , but this only seemed to increase his determination . Despite the fact the ACU were unlikely to grant him a license . We set up a test at mallory park to see how he’d get on . On arrival I found a very grey looking Fozzy . Who informed me his dialysis set up wasn’t quite what it should be and that he’d spent the previous night in hospital , despite being told he wasn’t allowed out to play he had discharged himself , but once the test was over he was returning to hospital.
He got on well with the bike and you had to give him 10 out of 10 for grit and determination , but it did worry me . A week or so later it became apparent that the ACU wouldn’t give him a license . As there were only 4 weeks to go until the season started , I had to search for another rider and Simon Morley said ” I’ve got just the man”.
There began my racing partnership with Ric Ballerini . Now Ric had been a top bemsee club rider for years and normally road GP 250’s , but unfortunately his garage burn’t down with all his bikes and gear in it (uninsured) . This was a major blow for him as he obviously wanted to realise his potential as a top national rider . He had many generous offers of help , but they didn’t quite add up to a competitive GP 250 ride . So rather than not race he did have just enough funds to race our ZXR400 in the bemsee nationwide championship . I was well pleased because although he hadn’t ridden diesel’s ( 4 stroke’s) before he would prove if the bike could win a championship.
|ZXR 400 Riden by Ric|
Because time was tight the first time he rode the bike was the practice day before the first race at brands indy circuit . It was obvious from practice he was quick . He managed second in both races which got him off to a good start . This proved the bike for me . Ric said he had to fight the front end all the time . I think this was probably because the ZXR is only a road bike and would never be as good as a GP250 . He went from strength to strength in first part of the season and won the next 4 races , but he decided to have a ride on a GP250 at Lydden hill and while battling for the lead came off and broke his hip . This caused him to miss 4 of the 400 races which dropped him right down the points . He fought back and the No1 result is shown in these Bike sport News clippings.
While all this was going on I was all set for my first race at Snetterton I entered the nationwide round of supertwins as it would be handy if Ric had any problem with the 400 and also meant I would get some moral support and advice . Having never been on a starting grid before in my life I knew I was in for a shock and it was a big grid 30+ bikes . What I couldn’t understand was how I ended up 21st on the grid when I’d never raced or qualified . I presume there were others like myself out there and the positions came out of a hat . I would much rather have been at the back of the grid , then if I stalled from nerves at least I wouldn’t get run down . The first corner was complete mayhem with the 4 bikes in front of me all leant on each other, but after that because Snetterton is such a big track it all seemed to settle down a bit . I made loads of silly mistakes but thoroughly enjoyed myself and came in 26th.
Over the remains of the year I did just enough races at different tracks to get my clubmans license and I spent my time learning the tracks , getting my tyres & suspension setup and improving my riding technique . I tried to take the no pressure approach because when I get the bit between my teeth and push that’s when it all goes wrong . I came off at Lydden trying to hard or as Jason Holland put it “you went into the corner & ran out of talent”. I had to work on my fitness , as I was very glad to see the last lap flag . By the end of the year I’d managed a couple of 4th places and felt I was beginning to develop a smooth technique .
One of the highlights of the racing season was the Team Ixion dinner dance .There’s nothing quite like getting pissed and singing really badly with a load of like minded individuals .I was honored to receive the rookie of the year award a finely broken KTM barrel hand crafted onto a piece of plywood .I did feel there were more worthy recipients there so I’m all the more grateful and solemnly promise not to take myself to seriously.
2003 I decided to do a full season and came 3rd in the supertwins championship.
Last year 2014 I came back to circuit racing after a long break . I’m racing with BMCRC again in the thunderbike championship . This is a class for pre 2002 bikes with a maximum of 130 bhp at rear wheel . This keeps the costs down and means I could still race the Aprilia RSVR and be competitive. I’ve had a great year for an old fart of 52. Finished 5th in the thunderbike etreme class. Having spent the year remembering my way round the circuits I cant wait for 2015 !
I have a lot of experience messing with engines and only do things I think will give me a visible result on the Dyno. Tuning an engine is not rocket science , but it does require extreme degrees of patience , especialy when it’s an engine you’ve never done before . All the results I have gained have been by trial , error and destruction testing .
I have an engineering background but no formal qualifications , so I have to do it the hard way . The days of shaving metal from conrods & rocker arms & then giving them a good polish has gone . Engine’s these days are built of top grade , lightweight materials that are made to tight tolerances , that can’t be matched in the garden shed . If you want to improve on crank & rods , you have to go the titanium route which few can afford to take and until someone gives me their bank account & says help yourself , I’ll stick to top end work .
I tend to use engines that have been well run in say 5k miles so they are nice & loose . The ZXR400 Kawasaki has been my most succesful result so far , apart from my 450hp drag but that had a turbo and loads of nitrous oxide which tends to make big hp’s gains fairly easy . Most circuit racers are looking for 5/10hp if there’re lucky just to give them a slight edge . This sort of gain is not easy to achieve on a small capacity bike like the 400 . If you get a good one you might see 60hp rear wheel on standard bike, if it’s a jap import probably 55hp .Our’s was 72hp after tuning .
Note there are some monstrous HP claims made for these bikes , so beware . Tuning an engine is really about bringing together the right collection of bits and pieces that work together . For instance there’s no point in doing all you’re engine work & then bolting an exhaust on the bike which wrecks the mid range power delivery , so you can’t drive out of corners . Most people start with an exhaust & jet kit , buy the best if it’s available Acropovich exhausts as seen on nearly all world superbikes are well made & light . Beware makers who claim large HP increases as these will have bigbore downpipes & reduce mid range .The ZXR is one of those bikes you can’t get an acropo for so I used an italian titanium road system with a race can . The micron race system works well on the ZXR . Race cans have little effect on performance as long as they are well made & light . It’s the downpipes that control engine performance .
Choice of jetting can be difficult , different manufacturers kits work better in different situations . It’s mainly the needle that’s the problem they’re never perfect . Usualy slightly to rich or to lean in the mid range once you’ve adjusted the top end . On the ZXR with no air box or with lid removed , I found the dynojet needles were reasonable , if you drop them to the lowest setting . I use 108/110 dynojet mains withh the aircorrector hole blanked . Idle 2.5 turns from fully in . The can , airbox & exhaust should see you upto 63hp . Make sure you have the 32mm carbs , also check bellmouth rubbers for shrinkage as they can get down to 26mm , not much use to a 32mm carb . I make my own bellmouths . Next it get’s expensive with cam , compression work & head flow . There is only one possible cam choice for the ZXR as nobody else does one , that is Kent cams regrind of the originals (it can only be done to euro bikes cams as there’s not enough metal in the jap one’s).You will also need adjustable cam sprockets , so you can set the cam timing .You will also need shims a lot thicker than standard , which I have to make . The porting is quite simple but time consuming , it involves cleaning the steps away from the back of the valve seats . knife edging the intake dividers & matching the intake rubbers to the ports . Japanese cylinder heads a very good already so you’re just tidying up the casting . Compression & squish , you need to bolt the whole thing together so you can measure vavle to piston & head to piston clearances . On the ZXR you can remove the base gasket & skim 0.5 mm off the head . Now you’re upto 66/68hp. As you can see it’s a longwinded process for quite small gains & the cost is mainly in the man hours ,though from what I’ve told you here you can have a go yourself .
I have seen some ZXR engines with lightened cranks ,I was unable to measure any difference this might have made on the dyno .It is supposed to help the engine spin up quickly ,but it can also cause the engine to loose inertia making starts harder. There were quite a few more tricks involving race airbox mods , ignition and more severe engine work , but they are alot of work for the last few hp’s .
Aprilia RSV / R
First of all you need to remove the restrictor from under the airfilter & cut the restrictor out of the original can . Many bikes are sold as full power but I’ve still found the restrictors in them . The first thing that was supposed to give a power gain was the acropovich can & big bore titanium side pipe .There was a considerable wieght saving over the standard can , but much to my amasement I saw no power increase and if the acropovitch does’nt give a power gain it’s almost certain that no other make of can will . I have also tested bigbore downpipes they give a couple of top end HP’s but create a nasty glitch in the mid range . 2 into 1 into 2 gives a slight increase all the way through , but it’s heavier & alot more expensive .
Next on my purchase list was a power commander on the Aprilia this only adjusts the fuel delivery .I found I could get just as good a result from an adjustable fuel pressure regulator and a well written race chip which can be had for £50 . So that gave me 112hp to go racing . I have now been inside the engine & have raised the compression to 13:1 & done some port work . The end result was a general gain of 3/5hp without damaging reliability , also the bikes standard starter motor can still cope .
Yamaha R6 is another bike I’ve had a fair bit of time to play with .I have seen 2 engines built by a quite famous tuner drop valves due to use of excessively strong valve springs . This is fine if you intend to rev the engines harder than standard & happen to be a factory team who rebuild the engine after every race ,but I have found the standard valve springs more than strong enough to prevent valve bounce .the standard inner valve springs are prown to failure ,but will usually last a season & usually give a slight loss of power warning before failure.Apart from the valve train these engines are strong . The original standard carb set up of these bikes can be very rough ,I’ve seen really rough power curves when they have been untouched .The first big power gain is the fitting of a race can or acropovich system for this you need to rejet ,the only jet kit to use on the R6 is the Factory kit (by this I mean the brand Factory rather than a genuine Yamaha item) .The standard air filter is as good as anything else ,on the race bike we run no filter just the wire mesh in the airbox to keep the gravel trap out.The standard cams in these engines have long duration this tends to damage the bottom end performance .I put kent cam regrinds in my engines they seem to work well .I have not tried the yamaha kit cams due to the high cost ,but they don’t look as though they would be any better. I do the usual port cleaning work ,skim the head for a bit more compression & for all that I get a gain of about 9HP over the original bike(which starts at 98Hp).The power delivery is very smooth and gives really good corner driveability . I have a few more little ignition & carb mods I do & also bigger rad to aid cooling which gets a bit marginal at times.Here are dyno charts for before and after .The standard bike shown in red was the best standard one I ever had on the dyno , some were as low as 92Hp , but they all had a power curve as rough as this .
Suzuki 1200 Bandit
I’ve done alot of rejet’s for cans on these bikes and know that you can get some ridiculous horse power from them usually at the expense of` rideability ,but I recently got around to tuning my buisiness partner Phil’s bandit . He had already cut the restrictor wire , fitted a race can , K&N filter in airbox and a dynojet stage 1 kit . This lot works well together , stick to the 104 main jets and you get a nice even 5HP all the way and much
crisper throttle response for bigger wheelies . Now I thought it would be nice to tune the engine so there was no loss of bottom end as he rides on the road all the time . So the engine got a set of kent reprofiled cams , compression hike and port clean the results can be seen on the dyno chart. I kept the original airbox , downpipes and stage 1 jet kit so the engine would’nt loose it’s nice bottom end driveability and the result surprised me . As you can see there’s hardly any change upto 6krpm and then it takes off .These engines still seem to suffer from top end oil starvation even though the oil pump is massive , so fit an external oiler kit which we can supply and use good oil .I’ve also seen a few gearbox failures mainly second the wheelie gear . These engines are commonly dragraced so there are some serious tuning goodies to be had , most of this is fine if you intend to drag race but can easily ruin a very tractable road bike.
In writing this I’m assuming my reader has a basic understanding of motorcycle technical jargon , As in compression damping controls the decent and rebound the return and preload is the initial pressure on the spring ( winding it up will not increase the rate of the spring ).Suspension is supposedly a black art that no mear mortal will ever understand . My experience is only of production based bikes . Pure race bikes tend to have adjustable geometry . Though adjustable yokes and swinging arms are becoming more available for production bikes .
The best starting point is a bike that has a well sorted geometry to start with . A fair indicator of this is a bike that’s popular for super sport racing such as R6 . I found that it was actualy fairly simple to arrive at some pretty good settings without even riding the bike if you followed a few basic rules on laden sag . Mind you I had some experienced advisors .
The first thing is to start with good kit . I always use Ohlins rear shocks as they seem to represent good value for money . There are of course many more to choose from .The basic idea is to have a shock that gives consistant results , so the damping oil viscocity does’nt vary to much with heat , the oil does’nt cavitate as it passes through the valves , seals do’nt cause stiction and you can go on and on . Thats why you buy a good quality shock because all the clever stuff’s been done for you . The front forks tend to be a bit more restrictive as most of us can only afford to modify the standard items . This can be done by a specialist (who if the bike is commonly raced will have a lot of base data to start from ) .
You can use these basic rules to find (usualy) a slightly heavier rate spring , Add some thicker oil (oil vscocities as stated by manufacturers vary tremendously so always stick to the same brand when testing for damping rates 10/15w). leave an air gap with the fork collapsed of 130mm and you’ll be in the ball park . Obviously having the damper valves modified by a specialist will improve on this , but I tended to wait till we ran out of damping adjustment then I new which way they needed to go .
Once you’ve brougth you’re shock you need to check out the rear spring rate , this is done by measuring the length of the chrome part of the damper rod with the shock fully extended . You should ignore the bumpstop rubber on the shaft .Having done this what you are looking for is when you sit on the bike and the spring compresses you should use a third of the travel of the damper rod . If this is not the case adjust the spring preload until it does use a third of the travel .
Next you need to check the unladen sag . This is the amount the back of the bike drops when stood up , so you’ll need to get a tape measure . Get a friend to lift the back right up and measure between a fixed point on the swinging arm and another on the tail unit , then let the bike stand on it’s own and measure again , the difference between the two is you’re unladen sag.This measurement varies from light bikes to heavy .Lightwieght 250’s will be topped out with no sag , a heavy 1000 may have 25mm , most production based bikes have 10-20mm.You must have this unladen sag after checking the travel and setting the preload .If you have no unladen sag then your rear spring will be to hard , if you have an excessive amount then the spring is to soft. Most shock suppliers will go on the safe side and give you a spring that is to hard . This will result in rear spinning up and being unsettled on corner entry to be the most noticeable affects . Pretty much the same set of rules apply to the front end ,the unladen sag at the front forks is usually about 25mm on most bikes . As far as damping adjustment goes , you want just enough to calm the spring when it rebounds . Compression damping should be felt when trying to compress the forks.