QuestionI HAVE A 85 HONDA 250R 3 WHELLER. WHIN I START THE BIKE IT IDLES FINE. WHEN I RIDE IT AND GO TO SLOW DOWN THE IDLE GOES VERY HIGH. I CLEANED THE CARB BUT IT DIDN'T HELP. I WAS TOLD IT WAS A VACCUME LEAK. BUT I CAN'T FIND ONE. ANY HELP WOULD BE GREAT! THANKS LUKE
AnswerLuke, high idles come from sticking carb slides, throttle cable routing or deterioration, low float level, throttle assemblies that are dirty or worn, spark timing that is advanced or air leaks in the intake manifold/carburetor.
When it goes to high idle, do you turn down the idle speed screw to see if that affects the problem? Idle speed is properly set when the bike is fully warmed up, not cold.
Check the gaskets on both sides of the reed cage and the intake manifold for leaks. Be sure all gasket surfaces are clean and flat.
The head gasket could be seeping into the combustion chamber. If you are using antifreeze in the coolant, it can burn like gasoline. Bit of a long shot there, though.
Check the ignition timing with a timing light to see if it is hanging due to some kind of spark control module problem.
Be sure that the carb float level is to specs and that the fuel tank and petcock passages are all clean and clear. The gas cap has to vent to atmosphere, too, in order for the fuel flow to be correct.
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Bill Silver
