Motorized bike bogs and dies, need help

Discussion in '2 Stroke Bicycle Engines & Kits' started by kodz, Jun 12, 2018.

  1. kodz

    kodz New Member

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    A few months ago I got a 2 stroke motorized bike kit and put it on a bike. It worked great, and I enjoyed it for about a month and a half. Then, randomly it started messing up. It would idle mostly fine, and rev normally. Then, when I disengaged the clutch it wouldnt push the bike forward but give sudden jerks shaking the bike. If I increased throttle, it wouldnt give any power and eventually popping/backfiring, leaving a small puff of smoke in the middle of the engine. If I was lucky, it would sometimes pull me along and drive fine but if you worked it too hard it would backfire and die. After backfiring once, it would get almost worse right after, even then backfiring during idle. The spark plug sparked fine, the headbolts were all tightened to 12 lbs, and the fuel mixture is 20:1. I had a broken piston ring, ordered a new one plus a new head gasket and still no luck. There was a tiny score in the cylinder.
     
  2. crassius

    crassius Well-Known Member

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    a CDI that is failing can cause backfires, but you should also check your compression
     
  3. kodz

    kodz New Member

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    I have thought about the CDI too but how should I check the compression?
     
  4. crassius

    crassius Well-Known Member

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    most auto parts store will loan a compression gauge for free
     
  5. sboricic123

    sboricic123 Member

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    I had a similar issue with mine and it turned out to be the exhaust that was blocked.
     
  6. kodz

    kodz New Member

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    Would a ripped up air filter cause it to have too much air? Sometimes with choke halfway it runs brtter.
     
  7. crassius

    crassius Well-Known Member

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    I would first test for an air leak.
     

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