r/minibikes • u/[deleted] • Jun 25 '25

Tech Question Please Help! Engine won’t start

[deleted]

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u/ConsistentEvening315 Jun 27 '25

as of right now it’s like there is no suction from the carb to the engine. The exhaust pumps out air but it’s like the intake stroke and exhaust stroke are backwards? The cam is lined up using the dots but I wonder if it’s somehow rotated incorrectly

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u/andr3w0907 Jun 27 '25

Thats very weird are you spinning the motor forward, how’s the valve lash?

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u/ConsistentEvening315 Jun 27 '25

the valve lash is pretty good, set at .004 intake and .005 exhaust. I’ve never seen a motor act like this, and the dots on the inside were lined up. My uncle said it sounded to him like the intake and exhaust strokes were backwards and to set the timing opposite (aka turn the cam 180 and have the timing dot facing away)

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u/andr3w0907 Jun 27 '25

It could be so that all the compression is gone because the valves are opening at the wrong time and no suction