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Fuel in the oil when running - CBF 500 Honda Motorcycles

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Fuel in the oil typically happens when you park the bike but do not turn off the petcock. If the float sticks or a float needle leaks the fuel will run in the manifold and past the rings into the oil. Back in 1983 the CB650SC (even when new) would do this occasionally for no reason whatsoever. If all your components are in good shape or have been replaced , the best way to eliminate the potential for this problem is to get in the habit of turning your gas off when not riding. If gas gets in your oil because you leave the petcock on , and all the carb components are in good order, your only option is to change the oil before continuing to drive. If you are having the problem while you are driving, take your carbs apart and clean them , place your floats in gas to check there buoyancy and consider new needle and seat assemblies.

Posted on Aug 04, 2010


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