JR80 pops & backfires

Discussion in 'Dirt Bike Mods & Maintenance' started by The Honda Pilot, Aug 9, 2017.

  1. The Honda Pilot

    The Honda Pilot Pro Class
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    I've got a suzuki JR80 that I use for cruising around my property as a pit bike. It recently started to pop and backfire randomly and now it is physically not ride able because of the popping.

    The bike still starts up first kick and will idle but as soon as you twist the throttle it will pop/miss and then backfire out the exhaust. Once it backfires it usually stalls the engine.

    From research online I've heard that most of the time when a 2-stroke does this its a sheared key on the ignition. I popped off the ignition cover and all looks to be well in there. No metal shavings and I can still see the key intact.

    Could it be a bad coil? Want some guidance here before I start buying parts. And no I haven't checked the compression yet. The top end has less then 5 hours on it.
     

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  2. truespode

    truespode Wheelie King
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    Stupid question but have you checked the gas for water? Does it have an oil injector? I would double check all of that for condensation.
     
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  3. The Honda Pilot

    The Honda Pilot Pro Class
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    I took the oil injector system off years ago. But haven't checked the fuel! I should though...

    I did change the spark plug & dropped the fuel bowl to clean it out.
     
  4. Okiewan

    Okiewan DRN is my fault.
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    So you are premixing then ... how old is the gas?
     
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  5. jaguar

    jaguar Subscriber

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    you looked and saw the woodruff key and assumed all is well. You can't tell by looking. You have to take it apart.
     
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  6. The Honda Pilot

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    Okiewan - The gas is roughly 2-3 months old. Non ethanol 91 octane and castor 927 @ 40:1.

    Jaguar- You are correct. I guess I will dig a little bit further.
     
  7. jaguar

    jaguar Subscriber

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    Also if the head gasket is leaking those symptoms can happen
     
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