Motorcycle Repair: cl77 fuel height in float bowl, pinhole leaks, fuel ratios

Question
hello, will measuring the amount of fuel that drains out of carbs indicate correct functioning of float, needle and seat? thanks in advance..

Answer
The amount of fuel in the bowl is governed by the float height, primarily. The 26mm carbs on a CL77 require a 22.5mm float level setting. If your carbs are "leaking" even when the float level is set correctly, then you may have issues with pinhole leaks into the float chambers and/or float bowl gaskets which are expanding with the alcohol in the gasoline and rubbing the edges of the float as they rise towards the top shut-off point. Make sure that the floats are squared up and even on both chambers.

Float level is set by measuring the height when the float tang has just touched the spring-loaded float needle tip, but not compressing the tip internally. Easiest way to check them is off the bike and turned sideways so the weight of the float isn't compressing the tip. Measure in the middle of the float at the cutaway of the carb body, where the float chamber retainer spring pivots.

Incorrect float height changes the whole spectrum of metering. High float levels will cause the engine to run richer and lower heights will lean out the fuel ratios. Set them as specified. I am finding that vintage bikes are running somewhat lean on today's fuel, so have to go up one size on the main jets on a stock bike with OEM air filters and exhaust with baffles. Any changes to the intake/exhaust may require further enrichening.

Bill Silver