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Sportster 883 engine still runs

Discussion in 'Motorcycle Tech Talk' started by chinotatbeer, Nov 4, 2008.

  1. chinotatbeer

    chinotatbeer New Member

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    When I ride my 2000 Sportster 883 C, once it gets pretty hot and I shut it off, most of the time the engine doesn't just turn off. For like 2 seconds, it wants to keep running.
    from what I know, it has a K&N air filter, screaming eagle pipes and was re-jetted.
    It seems to do it when I am riding it for a long period of time, so its extremely hot. If I go around the block, doesn't normally do it.
  2. chucktx

    chucktx Moderator Staff Member

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    your engine is "dieseling" or "running on" it is caused by hot spots on the piston and heads. this is usually associated with using low grade fuels. also too far advanced timing will contribute. what grade fuel do you use???
  3. Art_NJr

    Art_NJr New Member

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    Betcha it's jetted too rich - betcha. Carbon deposits build up from that & they'll get hot enough to ignite the mixture before the spark-plug fires & when there's no spark @ all. As Chuck referred to that's called "dieseling" 'cause diesels don't have an ignition system & fuel ignites by the heat of compression - not exactly the same as what you've got, but similar.

    Those carbon deposits also cause "pinging" - sounds like 100 little guys running around inside the engine, beating on the pistons with ball-peen hammers. Worse-case scenario you burn the edges off the valves & blow holes in the piston tops. I think you mentioned you didn't know what jets were in the carb - now would be the time to find out. 42 slow, 165 main is what you want - betcha there's a 45 slow in there.
  4. SPORSTERBOY

    SPORSTERBOY New Member

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    mine has done that since day one off the show room floor. prob for me it's the regular gas. doesn't make that tired horse sound all the time, so it must be what gas station I use.
  5. Art_NJr

    Art_NJr New Member

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    Just back the timing off - our Sportsters came from the factory set about 2 degrees too advanced to begin with. I don't have a problem 'cause I only run 93 octane premium & it's readily available, but if you're stuck with lower octane, just ease off the timing until the problem goes away.
  6. chinotatbeer

    chinotatbeer New Member

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    I bet its the gas. I use 87. I will start using 91 and see what happens. Is there like octane booster I can buy for Harleys? Like in a V8, you can add that bottle of octane booster when your gas tank is very low. Gives it some pep.
    Thanks everyone.
  7. Art_NJr

    Art_NJr New Member

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    Unless there's been some engine work done which would raise the compression ratio, your bike has 9:1 compression, is supposed to be able to run on unleaded regular without "pinging" or "dieseling" & adding octane booster would just be a Band-Aid. Sportsters up thru '03 tend to have the timing set a bit fast & are jetted a bit lean too (easier to pass emissions tests) & consequently, when re-jetting it's always been customary to go too rich. You need to just pull the float bowl & see what jets were put in - octane booster and/or adjusting the timing isn't going to solve the problem if the jetting's wrong & having seen it 1000 times, I'd bet it is.
  8. smiley7661

    smiley7661 New Member

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    ok.. now you have made me wonder about my bike. I have a 99 Electraglide with CV carb, have rejetted and runs really good.. but I asked a guy at Harley about adjusting the timing, and he told me it was fixed.. is that true ?
  9. Art_NJr

    Art_NJr New Member

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    I don't know about the Twin-Cam engines, but while looking up an ignition for a Sportster guy I noticed that the same ones for Sportsters (thru '03) work on BT's thru '99, so that means their timing is adjustable too. Best thing to do is get the factory service manual for your bike & then you'll know for sure how your system works.
  10. hotroadking

    hotroadking Super Moderator Staff Member

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    You can't change timing with the stock ignition module.

    However HD, Daytona Twin Tech, Crane, Dyna all make tuneable modules that will allow you to advance or retard timing curves, change spark all kinds of levels.
  11. REDHEAD

    REDHEAD New Member

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    :fight:
    I would try the 91/92 octane first ***then if no improvement***

    check plugs /see what the front one looks like
    should look gray-white with a tinge of lite brown okay (bet they are white or burnt gray away on the electrodes) LEAN ON GAS

    what color are the exhaust pipe ends???
    they should be a FLAT light black... If white gray WAY TOO LEAN on gas
    if sootie black way to RICH (i doubt)

    MY 1200 roadster diesels back when hot after a run if I turn it off before an average cool down for a block or two*** (idleing TOO fast will ALSO cause dieseling backwards on shut off especially when hot out and a hot run)

    signed....REDHEAD

    PS REMEMBER these engines are AIR COOLED that means no stopping and excessive IDLE this has a tendancy to run them backwards on turn off...
    HOT HOT not good for an air cooled engine

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