A mate of mine has a CBR1000F Locost track car that he's recently converted into a road car.
On the track she goes very well, however on the road she's very 'clunky' - let me explain.
When you have your foot on the floor she pulls well, and when you're braking she's fine, however when you're trying to maintain, say, 30mph she's very on/off, causing the transmission to sound very clunky as it pulls then releases.
He reckons it mught be do with the jetting - he is running her on an air sausage with 154 jets fitted (up from a standard 132 I think?). As I said, on the track she runs great (no 30mph zones around Kirkistown thank god!!), but for the road she's no cruiser. I can hear her banging away over my own car!!
Anyone else with a CBR1000, what jets are you running? Do you recognise the symptoms?
Any help appreciated.
Thanks again,
Ali

I believe mine is on the standard jets ( I havent looked ) and I do not have this problem.

But may I ask at what revs does this occur? I just sounds like the engine it bogging down when the revs are a bit low. mine is at 3000 rpm at 30mph in top.

HTH

James

hi chaps, im building a cbr1000F engined car, havnt got to the running stage yet.

Just our of interest what do they go like in comparison to a blade zx9 etc? im going to run a 3.62 LSD and 185/65/14 tyres.

Thanks for the replies. It seems to happen at low speed rather than at a specific rev range. I don't think it's the engine boggin down, it's just if you take the foot off the gas the engine really stops pulling causing the transmission to 'clunk'. It seems to be very on/off.
Colm, I suspect your car might be quite low geared, my friend Sean's car (CBR1000) has 15" wheels,quite high profile I think, a 3.54 live axel and she is still quite low geared for the road. His gearing appears to top out about 113mph or so, leaving 60mph cruising quite revvy.
The car is *slightly* slower than a blade/ZX9 car but it is still very quick. As a side note, I couldn't catch him round the track in my Indy Blade, mainly because he is a much more experienced driver than me!
Mind you I drive like a granny on her way to Sainsburys!
J - what air filter are you using? Is it the original airbox or are you running air socks/sausage?
Thanks again,
Ali

the slow speed "clunk" sounds pretty normal to me, there is a limit of course but they all "clunk" at low speeds whatever the gear............

colm

I am running a 3.36 rear diff with 195/50 R15 tyres. this gives 10.6 mph per 1000 rpm in top, I am looking for a 3.14 diff to make 70 mph a bit more civalised.

alister

I am running the standard air box with a holes & pipes in the side of the bonnet to feed cold air into the airbox


HTH

James