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  1. #1

    Don't over-torque your spark plugs

    Well after doing a million plug chops and endless tuning while chasing down a performance issue, I suppose I wore out my plug threads or just plain overtorqued them. Only seeing this issue on the MAG cylinder, but the ski otherwise runs great. Just a heads up though. I've got a few extra cylinder heads around here, so no biggie I'll grab one of them.

    BTW, I did notice that the MAG and CEN cylinder heads have a number 1 on them, while the PTO has a 3. What do those numbers mean? You can barely see it between the two head bolts closest to the rear of the ski.

  2. #2
    Hmm well now I don't know if I can use one of the cylinder heads I have lying around. They are all off a 650 and have a number 4 and a small "w". Opinions?

  3. #3
    Race, wreck, repeat delagem's Avatar
    Join Date
    Aug 2006
    Homer, NY
    Unsure on Polaris, but on Kawi's you shouldn't, for example, run a 440 head on a 550; too much compression, and WAY too little squish around the edges. Measure the diameter of the domes, see if there's a difference.

    I noticed the #'s cast into the heads, mine are mixed too. 2's and 3's as I recall. Not sure what they mean?


  4. #4

    Join Date
    Jul 2006
    Hays, Kansas
    I'd just put a heli coil in it and be done with it. Much easier than even changing the head.

  5. #5
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
    Join Date
    Oct 2006
    Cleveland OH
    No, don't use a 650 head. It's much smaller in diameter and compression would be raised along with incorrect squish as Delagem said. Ebay or look for someone parting one out. Not too keen on the helicoil, maybe in a pinch, but get another head.

  6. #6
    john zigler's Avatar
    Join Date
    Aug 2006
    i have 750 heads here 25.00 + s&h.

    try a new plug first. you may have just "squished" the plug gasket too much.

    send me an email if i can help.


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