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  1. #1

    Default Ironhead compression issue

    I'm working on a 77 ironhead and I had to set the timing. Got it all set and lined up pulled a compression check and I have 60 in the front and 150 in the rear cylinder. Code the timing or poi ts be off or sounds more like rings?

  2. #2

    Join Date
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    Cranking compression is purely a mechanical phenomenon, it has nothing to do with the timing. But, your first step on an ironhead would be to adjust the valves, then test again.

    Jim

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    Also, put a little oil in the cylinder that is low and see if it comes up. If it increases you have bad rings, if not it is in the valve train.

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    If I lift a head I expect to do a top end job.

    Ironhead top ends are not famous for their longevity and made lots of money for bike shops when they were more common. It's an antique design and that goes with the territory. They're lots of fun but the owner shouldn't expect it to be an Evolution.

    I inspect carefully because most of them are thrashed by the time they run badly enough to get attention. Otherwise customers tend to blame their piece of shit on the last mechanic who touched it. Note everything on the work order so the customer can't say they weren't warned. Carbon copy work orders are cheap in bulk and can save your ass.

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    Blake, did you set the ignition timing?
    Or the cam timing?

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