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post #1 of 6 (permalink) Old 03-08-2011, 07:10 PM Thread Starter
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Question compression ?

Is 120 both cylinders ok for compression on 86 SRV? I checked cold.

1998 Polaris Indy 500
1996 Yamaha Vmax 600
1991 Yamaha Phazer II48
1986 Yamaha SRV 540*Freebee*
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post #2 of 6 (permalink) Old 03-08-2011, 08:28 PM
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Is 120 both cylinders ok for compression on 86 SRV? I checked cold.
Original cans/pistons? If so, 120 isn't so bad. I'm getting 140 on new top end.

2004 Polaris 800 Edge Touring
Top End rebuilt - 2700 miles (5/1/10)
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post #3 of 6 (permalink) Old 03-08-2011, 10:50 PM Thread Starter
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Cool. I will wait another year. I got the sled for free from someone so I don't know what was done. I did find a circlip under the hood. I assume new pistons somewhere along the way.

1998 Polaris Indy 500
1996 Yamaha Vmax 600
1991 Yamaha Phazer II48
1986 Yamaha SRV 540*Freebee*
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post #4 of 6 (permalink) Old 03-09-2011, 07:51 AM
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I would open it up and have a look! But before you do, test @WOT and pull it 6-8 times real hard! Then add a few drops of 2 stroke oil in each plug hole and retest! If it goes up a bunch, atleast rering it!
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post #5 of 6 (permalink) Old 03-09-2011, 08:05 AM
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Cool. I will wait another year. I got the sled for free from someone so I don't know what was done. I did find a circlip under the hood. I assume new pistons somewhere along the way.
An easy way to take a peek at the piston, piston dome, rings and cylinder wall is to remove the exhaust manifold and shine a flash light into the cylinder. Move the primary clutch to move the piston up and down so you can see the entire piston and cylinder wall.

For what itís worth... We just replaced my buddiesí base gasket a few weeks ago and everything (piston, rings, cylinder) looked good. Two weeks later he seized the engine. We havenít opened it up yet, but we found metal deposits on the piston dome (PTO side). This suggests something broke off (ring, seal, bearing...) and was trapped in the cylinder. He had roughly 4000K on this top end and 7500K on the sled. So... even though everything looks good, the age of the engine, how you ride it and parts used (oem or other) determine the life of the engine. Hopefully you got a good one

Good luck out there!

2004 Polaris 800 Edge Touring
Top End rebuilt - 2700 miles (5/1/10)
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post #6 of 6 (permalink) Old 03-09-2011, 10:42 PM Thread Starter
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I would open it up and have a look! But before you do, test @WOT and pull it 6-8 times real hard! Then add a few drops of 2 stroke oil in each plug hole and retest! If it goes up a bunch, atleast rering it!
jumped to 190 with oil. New rings for that one.

I checked my other sled and it is at 125 both sides. Polaris Indy 500. With oil no change. I do notice an exhaust leak. Would that keep compression low or do you think it may be another gasket or something else?

1998 Polaris Indy 500
1996 Yamaha Vmax 600
1991 Yamaha Phazer II48
1986 Yamaha SRV 540*Freebee*
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