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  1. #1

    Seating piston rings

    I just finished rebuilding my '02 GPR1200R. New crank, one new jug and piston and new rings all the way around. I was meticulous in my rebuild, used plenty of assembly lube and assembled to OEM specs. I know that the rings need to be seated and that's what I attempted to do today. I only put an hour or so on the ski so I'm not sure if that's really enough. Before the maiden voyage, I had 100, 105, and 100 PSI on cylinders 1,2 and 3. I figured I'd see some improvement after the first ride. I did, but only 2-3 PSI. How long will it take to seat the rings and when should I be concerned? I know uniformity amongst the three cylinders is more important, but I'm a little disappointed in the results. I've checked the compression with two seperate gauges with the same results. I am running oil injection with amsoil 100:1 premix for the initial tank for the break in. Could this be slowing the seating process? How many hours should I give it? I was looking for all three cyliders to be around 115 which is where the were before the total overhaul.

    Thanks


  2. #2
    PolarisNut's Avatar
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    I've found that an hour or so of riding is usually enough to seat the rings. I ride mine at moderate throttle, with short bursts of WOT. The rings need load in order for them to seat. Temp of the motor will change pressure readings. I always test mine when the motor is cold.

  3. #3
    Well, that more or less sucks. Should I be concerned with the low compression or should I just keep riding and see if it improves? Or will it not really improve?

  4. #4
    PolarisNut's Avatar
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    Personally, I wouldn't worry too much about it. Atmospheric conditions will also change readings...hot, humid air, with a storm rolling in will lower the readings. Did you hone the cylinders?

  5. #5
    No, I didn't hone the cylinders. Personally, I thought they looked mint. I could still see all the factory cross hatch marks on the cylinder walls. No scoring or anything. I was under the impression that you couldn't hone the nikasil cylinders.

  6. #6
    PolarisNut's Avatar
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    Quote Originally Posted by iam026tb4u View Post
    No, I didn't hone the cylinders. Personally, I thought they looked mint. I could still see all the factory cross hatch marks on the cylinder walls. No scoring or anything. I was under the impression that you couldn't hone the nikasil cylinders.
    You can lightly hone nikasil. Its only a few thousandths thick though, so you can't change the size of the bore by honing, like you can with cast iron. I always pass a hone through before I re-ring...its not a huge deal though. It will just take a little longer for the rings to seat, since the crosshatching isn't "sharp". IMO, ride more, worry less

  7. #7
    Lake Mead Bum & BTLS Mark starflight's Avatar
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    It was my understanding that you don't use synthetic oils for break-in.

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