I am having a recurring flooding problem. Need some advice on the best way to sus out which carbi is the culprit. Bike starts ok. Sometimes I can go for a while and only have a problem when I stop at the lights, the revs drop to 500rpm. Have to pull over and turn the fuel off. Let the motor idle (500rpm) for about 1.5mins until the revs return then open the fuel again and off I go.
I have inspected the float needle and seat and all looks ok, (no obvious wear).
Have tried bench testing the carbies with the fuel pump on (all the carbies hold the fuel pump pressure.)
I can’t seem to replicate the problem unless on the road.
I am not getting any fuel coming from either of the vent tubes.
Anyone have any tricks to sus out the bad carbi?

could it be related to movement/vibration when actually on the bike? pipe not sealing properly or being at a funny angle perhaps?

did you check your valve tollerances ?

Is there any leakage from the carbs ... sounds like it could be a float bowl gasket, the leak causes the pump to keep petrol coming into the carb so flooding the bike

Taggy wrote:could it be related to movement/vibration when actually on the bike? pipe not sealing properly or being at a funny angle perhaps?

Sorry Taggy, what pipe are you refering to?

Evilchicken0 wrote:did you check your valve tollerances ?

Is there any leakage from the carbs ... sounds like it could be a float bowl gasket, the leak causes the pump to keep petrol coming into the carb so flooding the bike

Hi Evil, I did the valves a few weeks back, intake all exactly 0.17mm, exhaust all exactly 0.26mm

No leaks from around fuel bowl gasket, carbi mount rubber are soft, no cracks and to make sure of a good seal
have used a non drying gasket sealant.

THe only thing I can come up with is a leak and the needle/seat or the seat houseing O ring under pressure.
Problem is A) finding the replacements and B) they $#@* cost of of each one.

Added problem, I had to switch to reserve on the way home from work today, stop at a station and filled up.
Got down the road about a mile and the bike just died on me. I could get it started again and had to call a tow truck
the get it home.

the pipe that connects into the carbs from the tank i meant, could squirt fuel over carb looking like it's leaking?
the poor running after reserve could be crap from the bottom of the tank clogging things as the main fuel tube is higher than the reserve?

Muck in the tank would be caught by the fuel filter ... I guess you can have a look at it and blow through it to see if it's blocked.

You don't have a spare set of carbs for comparison ???

get a Honda...

CMSMJ1 wrote:get a Honda...

ha - image the electrical problems

I used to have a similar problem with my fzr600. It mainly did it when i had a full tank of fuel. My main symptoms were that it was not too crisp when you fully opened up and if you left it for say 5 mins with a full tank it would be flooded when you started up.
In the end i took the carbs off and rigged up a test fuel tank (borrowed one of a kart). I connected the fuel tank to the carbs and raised it about a meter above the carbs and sure enough i found out which one was leaking.
After a thorough clean up i tested the carbs again, problem sorted. Its been spot on ever since!