Thumper Club Forum
Club House => Chatter => Topic started by: andy230 on June 26, 2007, 03:27:36 PM
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Hello all,
I have a mate who is selling up his almost complete Aircooled Supermono Racer project. You know the usual story, bought with good intentions, to start (this) season, but he's run out of time and money, new girlfriend, garage space, blah, blah, blah... :)
Anyway, its a Suzuki RGV beam chassis, with a (hot??!) rotax engine. KR1S forks, brakes, wheels.
It has tanks, and a fairing, seat unit, bars, controls. Has header pipes and a can. Although rolling, it still wants a fair whack of attention. Maybe it is ridable, but I wouldn't be wanting to race it without a strip and check at the very minimum!!!
He's never run the engine, and neither had the previous owner (TC's very own John Goode). It turns over, but I'd be (at the very least) taking the head off for a peek...
Does anyone fancy a crack at the British Supermono Championship in 2008? There is at last one other RGV chassis in the class.
The price is VERY low, with the gentlemans agreement that the bike is on the grid in 2008. ie- no languishing in YOUR shed, to be punted on in a year or so's time!!! There's no V5 document, as its not a roadbike, with no intentions of being such. My mate is needing the room...
So come on, who fancies building up a racer and coming with me, Boyd, Mike, John, et al next year? Interested?
andy
ps. Disclaimer: motorsport is dangerous, doncha know? Honest gov, s'not my fault if you hurt yourself!
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Now the plan:-
1. come up with a cure for ME.
2. find a job / income
3. distract The Boss (SWMBO)
4. go racing
I think No1 is the hardest...
So how have they dealt with the Rotax having a RHS out put shaft and the Suzuki wheel being a LHS drive? RHS brake?
R
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Now the plan:-
1. come up with a cure for ME.
2. find a job / income
3. distract The Boss (SWMBO)
4. go racing
I think No1 is the hardest...
So how have they dealt with the Rotax having a RHS out put shaft and the Suzuki wheel being a LHS drive? RHS brake?
R
the swingarm is fitted in upside down!
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Ahh and the back wheel the wrong way round and the shock under the bike... lol
R
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I may have bought this bike, RGV VJ21A chassis, Rotax bored out to 604cc, KR1S forks and yokes, ZXR400 brakes, lime green KR1S wheels, advertised on Ebay last August in Slough from a bloke called Barry Johnstone?...Baz? I'm trying to get some history on the bike as I have none, I really need to know the engine spec.
anybody help?
John Goode?
Team humper?
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Yeah, you did buy this bike...!
hee hee! Small world! ;D
John Goode will be along and give you a bit of info maybe?
Done anything with the bike? Any intentions to race it?
(and I dont suppose you have a spare KR1S caliper??)
a
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When I bought the bike the cush drive bearing had collapsed because the spacer was missing so I decided to see if I could find a 17" rear wheel to give me better tyre choice. I have now fitted RGV250 VJ22 wheels, USD forks with gixxer internals and '22 race bodywork.
Was she raced? the reason I ask is that the fairing didn't have a catch tank,
anyway, so many questions, the main ones concerning the motor as I don't know what a safe rev limit would be,
I'm sure the brakes were off a ZXR400 but they were completely shot.
Any help much appreciated,
thanks in advance.
(ps I meant Thumper not humper) :-[
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Can't help you with any more info other than, when I obtained the bike (presumably in the same state as you got it from Barry?), from a guy from liverpool, who told me he had bought it from a man in the IOM who's son raced it over there a few years previous & then left it at the back of the man's garage & gave him permission to sell it as it was in the way!
I was given a phone no. of the man in IOM & rang him for info on the bike, the man himself (nice gentleman), although being as helpful as he could, did not have any more knowledge about the bike in question other than his son built it & raced it a few years previous with some success IN CLASS!, I have long since disposed of the number!
It just sat in my shed for a year (not touched) until I sold it to Barry (cheap) on the condition that he tries his best to get out on the supermono grid the following season. Obviously he could not manage that for whatever reasons? & the bike was sold on (AFTER GIVING ME FIRST OPTION TO BUY IT BACK), to yourself via e-bay???
So sorry I can't help any more in that respect, but really do hope you have success in the project & join us out there on the supermono grids SOON?
If I/we can help in ANY way towards this goal, then feel free to get in touch ANYTIME 01332609007 cheers, john........
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???
Isle of Man?, Liverpool? the plot thickens!
Thanks very much for your input. I saw the bike on Ebay and was looking for a winter project so took a punt. I never met Baz, the owner, as he was in Cornwall(?) with his woman, or something like that.
I didn't touch the bike until the season was over and decided to sort out the cush drive first and worry about the motor later. I've now got a decent rolling chassis. I turned my attention to the motor fully excepting that if it was shagged I'd probably have to look for another engine. I removed the filter cover and found a new filter and clean oil, (old oil, but clean),and a new spark plug, good news so far!. I then put some oil in the tank, removed the return pipe, and turned the engine over by hand to prime the motor. Within seconds oil was coming back,again clean but old, leading me to believe that the engine was already primed. This to me was all good news as it woudn't be in this state if it was blown or worn out.
I've had it running in the garage once and it sounds good ;D, I started it by backing another bike against it, back to back, and 'bumped' it. My neighbours are all pensioners and luckily deaf :P.
So, thats where I am at the moment, the unanswered questions are;
engine spec.....don't know
engine cc......don't know, I don't think she's 604cc
rev limit........don't know
As for racing her in the Supermono, the class may be out of my league, I'm just an average club racer (very average!) but may dip my toe later,Pembrey, Oulton?
I've checked out the bikes on the web site and they are so trick, amazing!
Thanks again for your help :)
Ps I tried to add some pictures but got lost somewhere?
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You could try talking to Sportrax (01822 841063) or the rotax man (www.rotax.co.uk - I thnk) about the spec of the bike - ie rev limits etc The cams usually have their 'spec' stamped on the end - 860 or 640 etc, these can then be looked at in the rotax or megacycle cata logs to see their duration. Guess you would have to lift the head to see the valves - but you could get some idea by popping off the carb and looking down the ports to see what dia the ports are and work from there.
My spec sheet for the standard 604 has 56 hp @ 7600 rpm - as a start not sure how much use that is. I have a poor photocopy of a dyno chart showing power produced to 8500 rpm
Just some ideas
R
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As for racing her in the Supermono, the class may be out of my league, I'm just an average club racer (very average!) but may dip my toe later,Pembrey, Oulton?
I've checked out the bikes on the web site and they are so trick, amazing!
Hello,
Nope, they're not out your league. I had never raced before, and have never raced in any other class. And I'm also slow, but novices are welcome. There are 2 classes for 2008- championship class (national licence holders and above) and the new Cup class (lower than national licence holders). There is another RGV Rotax in the class, #24 raced by Sam Gleeson. I heard from him last night, and he's definately in for next year too.
Good luck with the build! Keep us updated, its a sweet project
a
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Thanks everybody for your help,
:P
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8) Have to agree with Andy, it's definitely not out of your class (you obviously haven't seen me ride yet!).
You will find racers from both ends of the spectrum & of all ages, (ex world + current European & national champions, right down to me at the bottom end, but proud to be a part of it). I have fun taking part, & treat it as seriously as I can, given my personal curcumstances. If I can manage not to finish last, that would be an achievement, & that is my aim for this year, a better standard of riding than last year.
I also work hard trying to introduce new riders to the class, with some success for this coming season (apart from myself-dog slow, I have a young friend, Simon Bird (26)who will be racing in his first season, having had a couple of rides at the end of last season. He will be on an old tzr framed rotax which he already rides faster than me!, although I did manage to beat him in the last race of 2007 at Mallory by 0.77 of a second (whoopee!). My son, John(22) might join us later in the season after he has recovered from a couple of nasty offs & had a lot of practice. And I have just been approached by another GENUINE local lad (17) who wishes to give it a go, so I'll try to have him ready asap?.
So don't worry, you WILL enjoy it, no matter what standard. There is as much help as you want out there, just ask! & don't be afraid to be cheeky in your requests (you never know!).
So get that machine up & running, get some help & see you out there!!!!!!
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Thanks lads,
I've had a couple of days off work and got a bit done;
17" rear wheel in (wrong way round!) and spaced,
A torque arm made,
An offset gearbox sprocket fitted,
chain on and '22 bodywork modded, I 'tanked' the fairing with the thinnest aluminium I could find.
I'm waiting for a brake hose from Goodridge, longer than standard and I need to make a chain guard.
Now I need a reliable way of starting her, I live on a hill and I thought 'bump' starting her would be easy but BLOODY HELL! >:(......any suggestions? ???....I suppose my next project will be a 'Heath Robinson' starting device! ;D
thanks
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I generally
- Free the clutch off (usually sticky when cold)
- Stick the bike in second and pull it backwards untill I find compression.
- Clutch in, run like hell.
- Jump on the bike side ways and just as your arse hits the seat dump the clutch.
This is usually good enough to stop the back wheel locking.
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;)
I agree with steve's comment on starting, but if you have regular help, I think your best investment would be a set of rollers (with which you can start the bike up on your own driveway, or in the wet!), & a boon at the race meeting, (although there are always others in the mono paddock willing to let you use their's) Or, if your old & unfit like me, just sit on the bike & get your assistant to push!
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Thanks lads, are rollers available to buy or are they a 'homebrew' job? I saw a half a Mini-Moto used at Angelsey once and thought I might give it a try.
The last thing I want is to be running up and down the paddock with 5 minutes to go! :'(
It would be nice to fire her up on own, ie in my garage etc......powered rollers?.......hmmmm ???
I'll come up with something, I usually do! ;)
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If you are worried about the wrong way round wheel - I was on mine - the Aprillia 125 has a Rotax lump and thus the wheel has its drive on the right and brake on the left.
R
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Thanks lads, are rollers available to buy or are they a 'homebrew' job? I saw a half a Mini-Moto used at Angelsey once and thought I might give it a try.
The last thing I want is to be running up and down the paddock with 5 minutes to go! :'(
It would be nice to fire her up on own, ie in my garage etc......powered rollers?.......hmmmm ???
I'll come up with something, I usually do! ;)
In your garage???
Better have some bloody good earplugs handy!
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When I first got the bike the wheels were KR1s which I swapped for '22 RGV. I've just been sorting through parts ready for Ebay and noticed that the homemade chain adjusters that were used originally (KR1s has a smaller wheel spindle) has the words 'wotsit & thingy racing' scratched on them. Does that ring any bells with anyone?
I know it's a long shot but I would really like to trace the builder ???
Thanks in advance ;D
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I still haven't traced the builder, I'm probably going to wait until it explodes and find out the engine spec. when I rebuild her! The previous owner on the IoM didn't ride her (that's 3 in total!) but he was sure she came from Wigan and raced at Three Sisters. I have now taken her out on track ;D :D ;D :D ;D :D ;D, a couple of sessions at Oulton Park, I took it very steady to start with but pushed a bit harder in the second session.........very very happy, pulls like a train and steers well, needs a little setting up but overall I'm impressed, according to the TrailTech Vapor rev counter I'm using which records your highest RPM I touched 9000 rpm!!!! :o didn't feel or sound over-revved though but I better be careful!
to all of you who have helped thanks a lot,
canolman
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I've now got a little info on the motor,
560cc (not 604cc as advertised!!)
860 cam
34mm inlet valves
Gas-flowed head
I'm pleased overall but disappointed that she is a 560cc motor and not the 604cc, I reckon she makes about 50hp. I'm looking for more power!! The price of a big-bore kit is a bit steep as the casings have to be machined to fit a larger liner. I'm thinking of changing the 40mm Amal carb for something else, any suggestions?
I've raced her recently and was really pleased with the handling and the brakes are phenomenal!! ;D
I'd put the power to weight ratio on par with my CBR400 race bike but the 'mono would out-brake and change direction quicker.
A problem I think I'm going to have is beating the 105db noise limit, the pipe is a 2"bore straight through, if I baffle it I lose power :(.....catch 22, has anyone got any tips?
thanks.
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Hi There
I have a Mikuni 44mm (I think may be 42 with enough meat to become 44) that I picked up for my Rotax. Being as hell will probably freeze over before I get anything sorted if you are interested you could possibly 'borrow' it.
It is not a VM after market jobbie but is from some bike as original kit, but I understand all the jets etc fit just the same. If you like you may borrow it and see if you can get a manifold sorted for her, if she then jets up and you like the outcome we can discuss a price - she owes me about £50 I think - mind I might take the 40mm amal as a swap. If you do not like her just send her back - with the new jetting - and she will be there or there abouts for me if I ever get around to fitting it.
Would save you forking out for a big bore Mikuni only to find the Amal is easier.
AS I said if you like... above is only a suggestion - open to others - but keep them clean!
R
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Thanks Rog,
I'm in 'negotiations' at the moment and one of the debates we are having is whether to go bigger than 40mm, the arguement being that the inlet is 40mm so would a larger carb. bore actually create more power :o...something to do with velocity speed? :P. We are going to do a bit more research and see what we can come up with ??? . I'll give your big 'un ( ::)) a miss for now, thanks anyway,
:P
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It is an open offer - so bear it in mind.
I know there are lots of theories out there.. JR in his tuning books suggests that the carb should be
d^2/40=p where d is the carb diameter in mm and p is the power the engine makes.
If you are making 50 hp d = square root (50X40) = 44.7mm
He also suggests that there should be a taper from carb to valve so that the valve is approc 80% of the carb area
34mm = 907 X 2 = 1814 / 80 = 22.675 * 100 = 2267.5mm^2
2265.7 / pi = 721.76 *^-2 = 26.86 mm rad = 53.73mm dia
My maths may well be wrong and there are many many other factors - like midrange... but JRs calcs suggest that the valves are too big for the engine power or the carb is too small (40mm)
Mez porting (when he was alive) used to do a twin carb conversion for the Rotax so it could run 37.5 inlets and a pair of 38mm carbs. He also did manifolds to hold 44mm Miks
You probably know all of this anyway but thought I would throw it into the pot.
Best of luck
R