If your bike is running poorly, or not running at all, it probably has a carburetor problem?or three. Once properly jetted, carburetors don?t need much attention, but there are a few parts that do wear out and should be replaced as operation hours pile up. Lots of strong-running bikes have been fouled-up by unneeded or improper carburetor ‘service,’ so you should know what to do?and what not to do. Here?s what every rider should know before he even thinks of fiddling with his bike?s carb?

1: Some ‘carburetor problems’ might not be caused by the carb. Hard starting, poor throttle response at high or low revs, plug fouling and poor idle control are more often fuel, fuel supply or engine problems. Carbs rarely develop problems suddenly, so don?t tear the carb apart before you?re sure fuel is making it to the carb and that the engine and ignition are working right.

2: Constant or excessive fuel leakage, ‘dead’ small-throttle response and frequent plug fouling are common carb problems. Once you?re sure the carb is the problem area, you?ll have do some disassembly to find the cause(s). You don?t always have to remove the carb from the machine to service it. On most, loosening the intake tract clamps and turning the carb will give good access to its parts.

3: Pilot jets plug on improperly stored bikes, causing ‘dead’ small-throttle response. Remove the jet and clear it with solvent and compressed air. Avoid using wire, as it can distort the precisely-sized hole in the jet. If the hole is enlarged, the jetting will change, which could cause additional problems.

4: Worn or dirty float needles, incorrect float height settings or leaky floats cause excess fuel leakage and, in some cases, frequent plug fouling. Remove the float needle by pulling out the float hinge pin and the floats. The needle may come out with the float assembly or you may need to grab it with your dainty little fingers. Look for dirt or other debris or signs of wear on the tapered needle tip. It should have a perfect cone shape.

Carbs that have seen years of use can develop wear at the nozzle area. The nozzle is replaceable on older carbs. Most press out. The nozzle is cast as part of the body in newer carbs. All you can do to correct for the wear is run a ‘leaner’ needle?or replace the carb body.


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