Full Version: 98 XC 700 compression?
Polaris Files > Snowmobiles > Performance and Trail Sport > XC, XCR and other late model performance sleds
I have a 98 xc 700 and just wanted to know what the compression should be on this motor.
135 is ok 140 or better is nicer
QUOTE(Harrison @ Mar 4 2009, 04:27 PM) 
135 is ok 140 or better is nicer
Compression numbers vary with elevation, temperature, barometric pressure, etc. Get your engine good and warm and perform a compression test. You want to make sure that the cylinders are within 10% of each other. If they aren't its time for a rebuild.
The above is correct. I've was running strong @ 125 psi until about 10,000 miles and she started to feel weak on one when I pulled the cord. Pulled it apart, cracked ELKO piston ( no scratches or damage no stuck rings). Changed them both and still running on the same crank. I use synthetic lube in all my 2 strokes. I have rebuilt many of these with new cranks and they have more thump off the cord than mine did. The Ladies find them hard to pull them over when they are warm too. But they always start first pull with a primer kit even when it's cold at 25 below C and lower. Just load them with the primer until they almost stall until they warm up (lubrication!!!).
If I was going to my top end again. Just pull the full top end off with exhaust manifolt attached and install the updated aluminum base gaskets. Pistons of your choice (Wiseco, not a fan, they skinned me, no reply on warranty when I was dealing with the PWC 700 Polaris pistons) Iwould choose gaskets from a newer BIG block because we have had issues of them pushing out the sides after a rebuild. Then you have to take the whole thing apart again. I have matched up gaskets from 04 800's that will work minty as base gaskets on a 98 XC 700, go figure....The say it is always a matching case to block issue. But the metal gaskets are twice the price, but only $25 total and you won't have to do it again.
If I was going to my top end again. Just pull the full top end off with exhaust manifolt attached and install the updated aluminum base gaskets. Pistons of your choice (Wiseco, not a fan, they skinned me, no reply on warranty when I was dealing with the PWC 700 Polaris pistons) Iwould choose gaskets from a newer BIG block because we have had issues of them pushing out the sides after a rebuild. Then you have to take the whole thing apart again. I have matched up gaskets from 04 800's that will work minty as base gaskets on a 98 XC 700, go figure....The say it is always a matching case to block issue. But the metal gaskets are twice the price, but only $25 total and you won't have to do it again.
QUOTE(gjfenez @ Apr 22 2009, 02:21 AM)
The above is correct. I've was running strong @ 125 psi until about 10,000 miles and she started to feel weak on one when I pulled the cord. Pulled it apart, cracked ELKO piston ( no scratches or damage no stuck rings). Changed them both and still running on the same crank. I use synthetic lube in all my 2 strokes. I have rebuilt many of these with new cranks and they have more thump off the cord than mine did. The Ladies find them hard to pull them over when they are warm too. But they always start first pull with a primer kit even when it's cold at 25 below C and lower. Just load them with the primer until they almost stall until they warm up (lubrication!!!).
If I was going to my top end again. Just pull the full top end off with exhaust manifolt attached and install the updated aluminum base gaskets. Pistons of your choice (Wiseco, not a fan, they skinned me, no reply on warranty when I was dealing with the PWC 700 Polaris pistons) Iwould choose gaskets from a newer BIG block because we have had issues of them pushing out the sides after a rebuild. Then you have to take the whole thing apart again. I have matched up gaskets from 04 800's that will work minty as base gaskets on a 98 XC 700, go figure....The say it is always a matching case to block issue. But the metal gaskets are twice the price, but only $25 total and you won't have to do it again.
If I was going to my top end again. Just pull the full top end off with exhaust manifolt attached and install the updated aluminum base gaskets. Pistons of your choice (Wiseco, not a fan, they skinned me, no reply on warranty when I was dealing with the PWC 700 Polaris pistons) Iwould choose gaskets from a newer BIG block because we have had issues of them pushing out the sides after a rebuild. Then you have to take the whole thing apart again. I have matched up gaskets from 04 800's that will work minty as base gaskets on a 98 XC 700, go figure....The say it is always a matching case to block issue. But the metal gaskets are twice the price, but only $25 total and you won't have to do it again.
Pretty tough to pull the cylinders off with the manifold attached. The two inner nuts on the exhaust side are partially covered by the manifold.
Are the metal gaskets from Polaris or aftermarket?
With the pipe off, you can get at those two nuts, I have done it many times, use the box end and flip the wrench upside down. I matched up the metal gaskets from an 04 switchback 800 with paper ones, identical. Yes from Polaris and not much more expensive.
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