coming along well just waiting on a clutch cable from venhill and a fuel pump its currently running but then cuts out once it has used the petrol that was in the carb float bowls. hopefully have it finished soon, next on the list is chopping the roof off! how do you post videos on here? i tried to post one of it when i first got it running.

cheers

 

I post to You-tube or photo bucket and link it here like this.
http://www.youtube.com/user/rustyr01?feature=mhum#p/u/22/PxeXpuBvfnQ
This is a video of us a Dunefest 2011. Yes alot of people :-).. The CBR900RR motor in a quad is insane. This was without the 100HP of NOS.

I'm glad to see someone else putting these motors in an off road toy. Just be careful of the transmitions and speed shifting. We ruined ours this way. I just got ours back from the shop and will be putting it back in the quad. We use a NOS Fuel pump (for the CBR motors), and if you are running a K@N air filter and not the normal air box and exhaust, I can help give you a baseline of Carb jetting that my be useful for you.

Also make sure your Coils are grounded to the frame, and your ignition (Rectifier box (SP?)) is grounded to the frame. It is important for spark. If they are not grounded really well, you will not get good spark and you may melt some wiring.

 

hi guys this project is going well it is currently getting some bucket seats fitted and a roof chop going on got it running well only trouble is with the new fuel pump after about 3 mins of fuel pump running petrol squirts out of the carbs out of the hole left of the black arrowthat brass bit anyone know what can cause this and how to rectify it?

 

Hopefully others will chime in as well, but I believe there to be too much pressure. These bikes (post '95) use gravity feed fuel systems. 3-5 psi just may be too much. Whaddya think about introducing a tee after the bowls with a return back to the tank? so that the bowls will not overfill and pressurize- The air tubes are just letting "excess fuel" in the bowls out.

 

I agree 100%. When setting up our CRB900rr in our quad, we had the same issue. Gravity feed was not fast enough and we were running out of fuel, but a car (electric) fuel pump with a adjustable regulator on it was to much pressure and it overflowed the far right carb (as looking from behind the motor). We did purchase a NOS fuel pump meant for the CRB's and that fixed our problem. The NOS fuel pump was just as cheap as the others we could have bought and it has alot more flow (not pressure) then the stock ones...

 

cheers guys im using the stock cbr fuel pump but i think whats causing it is the fuel outlet on the standard buggy tank is for smallish internal diameter hose about 4mm ish where as obviously the cbr one is much larger around 15mm how ever this is on the tank side of the pump so i thought it would just neglect the pump of the correct amount of fuel.

rather than increase pressure as youd expect on the carb side of pump. i thought about a variable pressure regulator but im liking the idea of exciter900rr as it is near enough free, plus should reduce the pressure in the fuel lines reducing chance of a line popping off.


so where about exactly can i fit this t after the bowls? surely after the float bowls it goes to the jets? or am i missing something?

again cheers for all the help guys got the roof welded back on tonight and frame for the new seats so just this fuel problem and a new gear cable and its good to go.

 

Real quick, as I have only a crude idea, and limited time….. (2 DAY OLD baby, and a nearly two year old kid to run after)
What about a tee AT the inlet, with gravity keeping the bowls full, and the outlet of the tee going back upward and then off to the tank? (assuming the tank is hopefully slightly above the tank) That way there would still be a slight amount of pressure, but also an escape route for the excess fuel. the fact that the fuel would then have to travel upward would suggest that the bowls would be in the "sump area" of the fuel system, and not get bypassed at the tee until there was fuel in all four bowls. make sense?

at least thats my theory, and hypothesis…. lol like I'm a scientist….

It's up to you now to see if it really works in the "real world" though.
you'd also need another inlet fitting on the tank, but that's probably no big deal-

 

aye my mate reckond the same thing a t in the fuel line after the fuel pump then a line back upto the tank but to use a smaller hose for the return. will give it ago see what happens

cheers