Fuel leaking from overflow pipe

[jackwdwyer]

Hi, im new to this forum after just buying my first xr400. Its a 2002 model with a keihin carb.
The bike runs great apart from I keep getting fuel spilling out of the overflow pipe. The flow is not consistent, it can be fine one minute and then come flying out the next if the bike is moved.
I have set the float level to what the manual says and also everywhere in between with no joy. I know the float valve makes a good seal because i adjusted the float up too much at one point an no fuel was getting into the float chamber. The drain screw is also good and not leaking. The float valve is free and not sticking.
I have had the floats in water and they float well (dont know how good a test of the floats this is). The only thing i can think would cause the fuel to overflow would be a dodgy float or the float is catching something inside the float bowl. Can anyone else give any other ideas or anything that ive missed?

Also does anyone know where parts can be bought for the carb on this bike if needed, its a keihin?

Thanks, Jack.

[jamie92j]

how is the bike running on tick over? and through the rev range?

[jackwdwyer]

The bike runs fine at tickover and throughout the revs,
Cheers, Jack.

[africajim]

Keihin carbs on my Kawasaki, made by Honda, same issue, buy kit from Ebay and fit the new float needle, it's the only cure!
You'll make yourself sick stripping the carb over and over, checking float levels and it still pissing out petrol, new float needles!
Trust me,,, I'm a drunken Scotsman! (But I can fix bikes!)

[jamie92j]

sounds like the problem i had when my bike was dripping fuel same as yours, which turned out to be some dirt jammed in the carb under the float needle

did you clean all inside the carb when you had it apart? also have you checked the main needle setting and which level the clip is on?

also what jets have you got in there? check they are all standard size

[jackwdwyer]

Cheers for the replys. Do keihin use the same needles in all their carbs or do i need to search for an 'xr400 float needle'. Probably sounds like a stupid question but bikes and carbs are very new to me! I usually work on modern cars!
Cheers Jack.

[jackwdwyer]

@jamie. carb is very clean. I am not sure on the main needle setting will check tommorow and im pretty sure the jets are standard. Could the needle setting cause the fuel to overflow? One thing to add. it only comes out of the bottom overflow pipe and does it even with the engine off.
Cheers Jack.

[xr600shinbruise]

the petrol is leaking because the floats when rising and pushing the float needle into the valve hole is not shutting off the flow..99% of the time its usually debris dragged from the petrol tank into the carb and fouling the float needle hence the carb overfilling and exiting through the overflow pipe.check there is no crap in the bottom of your tank getting dragged into the carb, although the filter in the tap should stop this.i would try fitting a new float needle as it is a cheap part,try david silver honda spares.changing the height of the throttle slide needle will just alter the mixture,i would double check the height of the floats,look in your manual for float height settingsif all fails try and borrow another carb,good luck,mark.

[jackwdwyer]

Thanks for all the replys. I think ive cracked it. The brass overflow pipe in the float boal looked like it was very close to the float when fitted. I bent the pipe away from the float slightly and it hasnt leaked since. i will be using the bike tommorow so I will see how it goes,
Cheers, Jack.

[jackwdwyer]

I think I'll order a new needle anyway to be sure its sealing right. Dont want to be messing around like this too often!