No announcement yet.

Had my Cyl Milled .003", any issues?

  • Time
  • Show
Clear All
new posts

  • Had my Cyl Milled .003", any issues?

    I had my cylinder milled .003" to get rid of a low spot. The low spot was evidenced by a blown o-ring so I had the cyl decked until the low spot was cleaned up. Is .003" going to make much of a difference? I know it will raise compression a little, how about the squish, I don't know much about squish.
    2000 750 sxi pro, 81.5mm bore, probably going to get the 800 domes, (or put this head on my other ski and have it decked, it's still on the 80mm bore so I would use 750 domes.)

    Will decking the head get rid of the o-ring blowing problem?

  • #2
    Are you sure it was only .003" and not .030"? Because that is not very much. If it was only .003", then there would be no problems. But, if it was .030", then the squish clearance would be too close and you would need to custom machine the domes. Whatever you remove from the top(or the bottom) of a cylinder, decreases the squish clearance by that much. Your best bet is to assemble the engine and check the squish clearance with your existing domes. Start with a piece of .060" solder and insert it into the spark plug hole towards the front or rear of the engine. Do not go towards the exhaust or intake, because the piston will rock and the reading will be high. Make sure that the solder goes all the way to the cylinder wall and turn the engine over once by hand, or just bump the starter. Now remove the solder and measure it at the thinest spot with a caliper. You want to check both sides of the cylinder, front and rear. You don't want any less than .040" squish clearance. If it measures in the .030" range, recheck with a piece of .030" solder. If the solder is too thick, it won't give the correct reading, it will only compress so much.

    Good luck!
    Brooks @ ADA Racing
    Facebook, YouTube, eBay, Twitter
    Use Coupon Code: 'bb10' to $ave!


    • #3

      I checked the receipt last night and it was .004". Not much at all. I'll check the squish with the solder.