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Samuel Jerome Morris

Old 1989 Yamaha big bear 350 won't start

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I have an old '89 big bear 350 that I am having trouble with . I have cleaned the carb , install ed a new stator , pulsar coil , ignition coil , CDI box ,new plug ,  timing is dead on , and a new intake boot , compression test says 125 lbs . When I crank it over it will start , but won't run it acts as if it's either got a bad vacuum or compression leak or is out of time . If you have any input maybe it will help I am about out of ideas .  When I got it it was not firing and the guy said he had it idling and it just died and wouldn't start . I have ordered a new carb but have my doubt's it's going to help because this is the second carb I have cleaned and installed on it . Any Ideas ?

Edited by Samuel Jerome Morris

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It sounds to me like it might be fuel starved. Have you tried manually giving it some gas or starting fluid through the intake to see if it runs?

* Topic moved to Yamaha forum and added year and manufacturer to topic title.

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Yes I tried that also . I did finally get it started it ran about 5 minutes and died now it's not firing . I am beginning to think I may have sone sort of ignition coil or wiring problem . Will update as soon as I figure it out ! 

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Ok  got it firing and now it will start . Problem is it just sits and kinda idles like an engine out of time and if i touch the throttle it dies immediatly . I have cleand the carb and then pulled the carb off another one i have and swapped them it runs great on the other bike and mine does the same on this one barely idles . I have checked for clogged exhaust , made sure fuel flow is good checked valve lash and timing . I am out of ideas i think i will pull the head next and check the gasket . The compression is around 130 lbs . Im lost ! Anyone got any ideas ? HELP !!! 

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