Little Help...

Discussion in 'Engine, Fuel and Exhaust' started by Archell, May 14, 2008.

  1. Archell

    Archell New Member

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    Hello everyone!! A friend of mine has a sportster that had been sitting up for a while and wouldn’t start. Went to take a look and the plugs weren’t firing – changed them out and it started like a champ. Let it run for about 20 minutes and it sounded great so I decided to take it for a spin, but after cruising for about 10 minutes it started to backfire and eventually crapped out and wouldn’t start. Let it sit for about 30 minutes and then it fired back up. It was still backfiring, but after idling for a while it eventually stopped so I took it for a spin again. Same thing – ran great through the whole range of rpms, but after about 10 minutes it started to backfire and crapped out again. This happened one more time. Anyone have any ideas? Strange thing is it runs really well for a while, but once it warms up it starts to backfire and then dies. Thanks in advance.
     
  2. Archell

    Archell New Member

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    Hobbit - since it had sat up, the first thing I did after I got it running was to flush the fuel system / carb with solvent and I pulled the air filter just to make sure it was getting plenty of flow...

    Gary - is there anyway that would only happen after it runs for a while? I was running it at 65mph - it was purring and had plenty of power, but after it had run for a while the problem started...Same way each time...

    thanks again
     
  3. Vibratinharley

    Vibratinharley Junior Member

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    Sounds like ignition module or what happened on my sportster where ignition pick up was bad. When it got hot it would back fire and shut off, let it cool down and it would be fine till it warmed up again.

    my $.02 worth
     
  4. glider

    glider Veteran Member

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    Have you given the tank a look to see if there is any water or sediment in it?
    Best bet would be to remove it and flush it out with some fresh gas and then recheck the float bowl on the carb. Dump it into a clear glass and let it settle to see if any water settles to the bottom. Sounds like it could be some water from your description. When it stops running, check for spark at the plugs also.
     
  5. glider

    glider Veteran Member

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    The key here is to start at the beginning to track the problem down. By this I mean start at the tank, then move to the outlet, then carb otherwise you end up cleaning the carb after the tank again again because of something that may have been passed back into the carb after it was done first.