Carb overflowing

[morg_nz]

just rebuilt my top end - new cylinder, pisotn etc.

put it back together and now the carb won't stop overflowing. its overflowing non stop out the overflow which comes out of the bowl at the bottom of the carb.

any ideas?

cheers

[Taz]

Tap the bowl with the handle of a screwdriver as a first step.

[noobi]

float valve will be stuck, if you didnt play with the carb during the time it was off the bike, then it should work now, just tap the float bowl with something as Anthrax said, it can take awhile and a lot of tapping.
If that still doesnt work then the float setting has to be reset.

[morg_nz]

float valve will be stuck, if you didnt play with the carb during the time it was off the bike, then it should work now, just tap the float bowl with something as Anthrax said, it can take awhile and a lot of tapping.
If that still doesnt work then the float setting has to be reset.

lol i did play with the carb while it was off - set the float height correctly. I just had it off again. the floats seem to move freely, i.e. not getting stuck (the screwdriver tapping didnt help either). I pulled the float needle and seat, and they seal perfectly, i cannot blow through them. But when i put it back together and blow down the fuel inlet line there is the faintest sound of air getting through - nothing compared to how much air goes past when i open it, but just a whisper. what i noticed though was that there is an oring on the outside of the brass valve seat, which provides a seal between the seat and the carb case. the oring is smaller than the groove it sits in, i wonder if it is small enough that some petrol can get past and cause it to overflow? mind you i was blowing past it, whereas the petrol is just gravity.

its a bugger really cause the bike is running so well with the new cylinder and piston, its just pouring petrol even while its running!

[vr4king]

Is the carb sitting LEVEL?

I had a similar issure on a cr125 all i had to do was turn the carb slightly in the boot and it stopped.......This was after i set the float height about a dozen times easiest way i found was blow in the intake and slowly move the float till it blocks the air flow then measure it there

[cambocambo]

I have this problem and there was a little bit of dirt in the bit that the float valve connects to. (the name escapes me now) and it was holding the fuel inlet open. Cleaned it out and the floats would close the valve and all was good again.

[awayatc]

when you say you adjusted float level .....
does this allow for bike being on sidestand...?
i.e does it overflow as well when upright?...

[morg_nz]

when you say you adjusted float level .....
does this allow for bike being on sidestand...?
i.e does it overflow as well when upright?...

bike is never on a side stand, but yes it overflows constantly when upright.

Just figured out what the problem is though, i took the bowl off the carb, and tried holding the floats up to close the valve and still petrol trickled past, then with just the needle only. so it must be the seat/oring. and then i had a good look at the oring, its got a flat spot about 5mm long on one side (i must have knicked it when i put it back in the other day) guess i'll have to wait till monday to get a new seat kit. bugger!