Carb question

[Chuey]

On one of my R100 bikes, the right carburetor has a problem I don't understand very well. At idle it does not leak. At speed, it leaks and gasses up my boot. It seems that the wind makes it leak through the bowl gasket. I put a new gasket in and it still did it. I did that with the carb still on the bike but I'm pretty sure the gasket was on correctly.

Is this likely to be an issue with float level? I have the offending carb off the bike so if it is, I'll go to the book and see how I'm supposed to adjust it.

Thanks,

Chuey

[jagarra]

Sure sounds like the wind is creating a venturi effect, pulling fuel into the carb. Do you have any air leaks on your tubing going to the air filter?

[Duane Ausherman]

First I would be looking at the float needle and seat. Have you done the standard checks for float level etc?

[SteveD]

After checking the needle & seat...
Sticking float? Tap the carb with a mallet.
Is the invisible "paperclip" in correct position?
Is the float binding on the float pin?

[Chuey]

Thanks. I'll check the float level tomorrow morning. I'm pretty sure the paper clip is in correctly.

Thanks again.

Chuey

[robert]

Might want to weigh the floats. A heavy one may drop while running.

[barryh]

+1 on measuring float weight especially if the floats are old.

Setting floats parallel or measuring fuel level in a removed bowl simply doesn't work accurately unless the floats are known to weigh close to new which is 12.5 - 13 grams. They can work OK up to 15 grams but they will produce a higher fuel level unless compensated for by setting below parallel or targeting a few mm less on the level in the float bowl. Above 15 grams they should be replaced.

[George Ryals]

This has come up before. Right carb leaking only at speed. Bings have a vent hole coming directly from the float chamber. I seem to remember that the guy had big feet.
Try making a test run with the ball of your right foot on the foot ped instead of your foot shoved up under the carb. The theory was that air currents around his foot caused a low pressure that sucked fuel out of the vent hole.

[Chuey]

I checked the float level this morning and it was text book. It is back on the bike now and it runs well (it never had a running problem related to the stinky boot syndrome). I didn't have time to ride it before work/after putting the carb back on.

I did not see the admonitions to weigh the floats but they were very white and seemed "fresh" if that word works. If I get any symptoms, I'll weigh the floats. I will check my foot position while on the freeway but I know as soon as I get into any traffic or handling situations, I have the balls of my feet on the pegs.

Thanks,

[MCrenshaw]

May we assume that you have the stock air filter and tubes installed from the carbs to the air box?