bike carb problems

[retrojoe]

Hey,

looking for some advice and I know there are lots of clever minds here... so heres my question...
basically Ive got a 8v vitara engine with a set of cbr 600 bike carbs on it. I want to get the car MOT'd pretty soon and the engine runs ok but the carbs are flooding loads out of the overflow pipes.
would incorrect float levels cause this?
and the carbs are running from the standard mechanical pump on the engine, could it be to much pressure?

thanks for the helo guys!

Joe

[deaddave72]

if this is a new challenge thats occurred then it could be the floats needing adjusting (not familiar with bike carbs) . I would check to see what pressure the fuel pump on the CBR puts out and the fuel pump on the vitara is supposed to put out. That will at least give you an idea if thats the cause, if so an adjustable pressure reg will be all thats needed.

Sometimes carbs will have an overflow pipe that feed back to the fuel tank, once again, check that the carbs being used had this feature and that this is whats needed.

Hope that helps a bit

[retrojoe]

Thanks mate, that does help a bit.

I was told that the two pipes thar are overflowing can just vent to atmosphere, so I don't think there ment to return to the tank.

I will have a look into the fuel pressure. Unless anyone here knows what pressure a standard mechanical pump kicks out? I think bike cardb should be around 2psi.

[Dez]

id fully expect your fuel pressure is too high if its unregulated. get a pressure reg (ive found the cheapys from McGill motorsport to be surprisingly good/accurate) and set your pressure before you start messing with anything else.

[retrojoe]

That I will do!
I actually have a cheap regulater. (but it's in work and I won't be able get it until Monday which is a bit annoying)

Are they easy to use? As I'm not really sure how to set it up.

[Dez]

plumb it into the fuel feed, turn it down til the carbs stop curse word out, and thats about it really. ive got a similar setup of cbr600 carbs on a cg13 micra engine and thats reg'd down to about 2.5-3psi and works just fine. without the reg it did exactly what yours are doing.

[retrojoe]

Brilliant. That's a load off my mind. Thanks very much mate.

How do you find using the cbr carbs? I haven't used mine on the road since I installed them

[retrojoe]

one last thing!

my fuel pressure regulator has a 3rd pipe coming out of it. I guess its a vacuum pipe to change the fuel pressure under different loads?

do I need to hook this up to anything or is it just for injection engines?

[Neil]

I used the self regulating pump from the bike I got the carbs off (ZZR1100) to an ignition live, works a treat.

[Kieran]

If the carbs aren't sat at a similar angle to the bike they came off, they will flood.

Most bike carbs are semi down draught, so want to be mounted around 45 degrees for the float valves to work properly.

[collector]

don't rule out worn float needles !

[gavs1]

9 times out of ten it's because the fuel presure is to high, most bike carbs r only gravity fed, it's best to use a pump from a bike that has 1, iwe always try to keep the line between carb and float bowl as level as possible