Need help with carb issues

Richard Tool · Mar 23, 2024

Helping a buddy out with his 2005 T 100 . Keihin CVK carbs . Experiencing intermittent flooding out of overflow tube . I have had the carbs apart in the float bowl areas . Floats not leaking . The floats are pivoting on the hinges with no apparent issues. Float valves and seat seem to be in good shape . The only path that I can see to the overflow tube is through the float valve . What am I missing? Thanks in advance for any input.
RT

concours · Mar 23, 2024

Richard Tool said:
Helping a buddy out with his 2005 T 100 . Keihin CVK carbs . Experiencing intermittent flooding out of overflow tube . I have had the carbs apart in the float bowl areas . Floats not leaking . The floats are pivoting on the hinges with no apparent issues. Float valves and seat seem to be in good shape . The only path that I can see to the overflow tube is through the float valve . What am I missing? Thanks in advance for any input.
RT

Float valve seats encrusted with residue from storage.

Polish with a tapered wooden dowel (chopstick or kitchen match) laden with Mothers Mag.

Seen it a lot.

baz · Mar 23, 2024

Check the viton tips on the float needle for damage
I use a Qtip in a cordless drill with metal polish to clean the seat up
I'm not familiar with these carbs but if all else fails the float needle valve seat should be removable
This will have an O ring seal on the outside that may be letting by

mean gene · Mar 24, 2024

No good dead goes unpunished!

Richard Tool · Apr 4, 2024

New float valves and polishing the seats seems to have done the trick . Thanks fellas for the tips .

Richard Tool · May 7, 2024

so back to square one . As noted above, polished seats and replaced float valves . With carbs temporarily mounted level on test stand COULD NOT MAKE THEM LEAK .

Owner back from Florida so we reinstalled carbs on bike . Leaking as before. Same size fuel line on test stand and bike - WTF ?
Any ideas anyone?

concours · May 7, 2024

Richard Tool said:
so back to square one . As noted above, polished seats and replaced float valves . With carbs temporarily mounted level on test stand COULD NOT MAKE THEM LEAK .
View attachment 114217
Owner back from Florida so we reinstalled carbs on bike . Leaking as before. Same size fuel line on test stand and bike - WTF ?
Any ideas anyone?

While it's running?

Richard Tool · May 7, 2024

concours said:
While it's running?

Both - running and off .

concours · May 7, 2024

what are the floats like? Plastic? Brass?

Lineslinger · May 7, 2024

Crap/crud in tank or delivery lines re-fouling seats or float needles.
I had a fine particle issue that would only show up when fuel tap was on fouling float valve. It was fine enough to get through bowl inlet filter. It only takes speck or two.

Richard Tool · May 7, 2024

Lineslinger said:
Crap/crud in tank or delivery lines re-fouling seats or float needles.
I had a fine particle issue that would only show up when fuel tap was on fouling float valve. It was fine enough to get through bowl inlet filter. It only takes speck or two.

There is a new in line fuel filter.

Richard Tool · May 8, 2024

concours said:
what are the floats like? Plastic? Brass?

Ha - I don’t remember but I think plastic. Both floats were individually held under in a jar of gas for a few minutes with no bubbles/leaks . When I had them on the test rig I shut the fuel supply off and on a few times and tilted the stand and as stated I could not make them leak . The owner is going to lightly knock the float bowls a few times and try again . If still leaking off they come and will open them up again.

baz · May 8, 2024

Richard Tool said:
There is a new in line fuel filter

Did you check the O ring for perishing as post 3 ?
I'm not familiar with these carbs
But I've had the issue a few times with mikunis
Especially if they have stood for any length of time and the O ring dries out

concours · May 8, 2024

baz said:
Did you check the O ring for perishing as post 3 ?
I'm not familiar with these carbs
But I've had the issue a few times with mikunis
Especially if they have stood for any length of time and the O ring dries out

I did a rack of carbs for a friend's Bandit last summer.
I spent almost $100 just on rubber parts, proactively.
Including all the above mentioned o-rings.

Carlos Hathcock.

Need help with carb issues

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