Question by staldantes: Why would I be getting suction from the exhaust? Timing appears to be correct.?
Using the kick start to turn the engine, by putting my hand over the exhaust tubes I get suction for a moment. Bought bike as a non-runner, but timing belts appear to be in the correct position. Ducati Desmodromic valve system. Cagiva Elefant 650

Best answer:

Answer by blackfirebeetle
are both valves closed ok on the power stroke ? have you got good compression ? it sounds like dodgy valve timing to me.only needs to be slightly out , get a workshop manual and check thoroughly . good luck !

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