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Timing/Pamco/PMA isssues

Discussion in 'The Garage' started by Honkytonkrob, Aug 10, 2019.

  1. Honkytonkrob

    Honkytonkrob XS650 Member

    I recently bought a bike that has a pamco and PMA installed. It runs good but idles a little high....around 1600Rpm.

    The line that was marked on the PMA for timing is always way to the left of center bottom...no matter now much I regard the pamco. Seems to run fine, I just don’t want to wreck anything. The advance looks closed at idle and slowly opens up as throttle is increased.

    Since it’s running fine maybe the installer of the PMA marked the timing wrong?

    Should I worry about this?

    Also, I’ve noticed It’s hard to find Pamco xs650 instructions from the manufacturer. One website is down that search results direct to find them.

    Any thoughts or suggestions are appreciated!
  2. Gator xs2

    Gator xs2 XS650 Addict

    Have you tried backing down the idle screws a touch? I think when bikes warm up the idle changes to a little on the high side.
  3. Honkytonkrob

    Honkytonkrob XS650 Member

    It’s pretty much as low as it goes. It will idle lower if hold the throttle at the carb down. Cable issue likely....even when holding it down the line is still way advanced for timing.
  4. Jim

    Jim Beyond the edge, is the unknown. Here be Dragons XS650.com Supporter Top Contributor

    Well I certainly would. The (possible) consequences of the timing being too advance is a very costly topend to replace holed pistons. Maybe it's fine... maybe not.
    Me, I'd want to know for sure what the timing is.
    Last edited: Aug 10, 2019
    TwoManyXS1Bs likes this.
  5. Honkytonkrob

    Honkytonkrob XS650 Member

    If I have no reference from the original system on the bike for timing marks how do I figure these out?
  6. Jim

    Jim Beyond the edge, is the unknown. Here be Dragons XS650.com Supporter Top Contributor

    TwoManyXS1Bs and Honkytonkrob like this.
  7. Honkytonkrob

    Honkytonkrob XS650 Member

    Thank You!

    These terms are new to me. I really appreciate the direction.
    Jim likes this.
  8. wildav

    wildav XS650 Enthusiast

    How much lower will it idle when you hold down the carb lever ? The cable could be positioned in the wrong path coming to the carbs causing it to idle up. If that's the case then the mark on the magnet may have been used as a reference for installing it on the crankshaft. Still a good idea to get a timing light on it as Jim advised after you get tdc located and properly marked. It isn't too difficult.
    Jim likes this.
  9. Honkytonkrob

    Honkytonkrob XS650 Member

    Going to order a piston stop today. One concerning thing is that even when I used a timing light with the original owners timing mark, moving the pamco plate didn't seem to change the position of the mark forward or back.

    Things runs great but seeing that mark so far forward is scary!@
  10. 5twins

    5twins XS650 Guru Top Contributor

    Your idle speed is high so the timing may be advanced already. It shouldn't be fully advanced by 1600 RPMs, but it might be beginning to advance. Honestly, you'd have to pay me to run a PMA, and pay me a lot, lol.

    Sounds like your carbs may be way out of sync and that's why you can't get the idle speed to go any lower. You should be able to turn it down to basically nothing and have the bike stall on you.

    That mark on your PMA probably isn't for timing, it's probably TDC. You use that for setting the valves. Timing is set at 15° BTDC. The original systems have a separate mark for that and sometimes another for fully advanced timing (40° BTDC).
  11. peterg

    peterg XS650 Addict XS650.com Supporter

    Hugh’s Hand Builts has good instructions for setting timing marks including a label.

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