Lower Gaskets

Discussion in 'Sportster Models' started by TheJudge, Jun 26, 2011.

  1. TheJudge

    TheJudge Member

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    I found out I have a slight leak in the lower gasket on one of the cylinders on my 91 Sporty. I know I need to repair this, but the funds are limited right now, and it is not a DIY job for my level of experience. How urgent of a repair is this? I keep an eye on my oil level. I'm not losing oil quickly, but I do see the leak after a day's ride.

    Brian
     
  2. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    It is fairly common for the base gaskets to get blown on the evo engines it is not a particularly difficult job to replace them it just takes some time and effort
    however you should be able to run the bike for a while with the gasket blown but it will make a mess with the oil and will get worse with time
    if you are going to run the bike do go easy on it
    Base gaskets are often blown by riders not warming the bike up fully before using full power
    as the cylinders are alloy and the studs steel they expand with heat at different rates this puts extra strain on head and base gaskets during warm up period of the engine

    Brian
     
  3. glider

    glider Veteran Member

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    Like Fin mentioned, the EVO paper base gaskets are notorious for seepage or leaking. If you replace them, go with a quality replacement instead of the stock paper ones.
     
  4. TheJudge

    TheJudge Member

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    How long should I allow the engine to warm up before I move out? I have no temp guages - just a speedo and tach.

    Brian
     
  5. glider

    glider Veteran Member

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    The safe answer is a few minutes until you feel some heat in the head or rocker area. It will make a difference in the long run.
     
  6. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    I start the engine then put my gear on jacket gloves helmet glasses then i can back the choke of to 1/4 and ride the 1 mile into town slowly and when i pull off from the junction into town back the choke off ride through the town and as i pass the end of speed restriction sign i am good to go

    Brian
     
  7. TheJudge

    TheJudge Member

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    Thank! I'm going to get the gaskets replaced this weekend. The warm up info is very helpful.
    [​IMG]
     
  8. Jack Klarich

    Jack Klarich Expert Member

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  9. ctg332

    ctg332 New Member

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    hello what is the best sealant to seal crankcase halves on 1979 sportster? Thanks Tom