I have a 03.5 Blair morgan 800 and did a compression check last night. The sled is brand new and I got about 133 per side. My brother has the same sled with about 1000 miles on it and he is just over 150 per side. Tests were done with the same guage. My question is why or how do these come from the factory so different? What can I do to get it where it should be? Thanks.

Originally posted by EAGLE17@Sep 19 2004, 05:38 PM
I have a 03.5 Blair morgan 800 and did a compression check last night. The sled is brand new and I got about 133 per side. My brother has the same sled with about 1000 miles on it and he is just over 150 per side. Tests were done with the same guage. My question is why or how do these come from the factory so different? What can I do to get it where it should be? Thanks.
346187
if your sled is brand new, barely run, then chances are your rings havent seated yet. these generally take a couple of tanks of fuel to get them broken in well.

I agree with machz1, just not broken in. And dont forget you should always hold your throttle wide open when doing a compression test even thou sometimes it wont change the reading....joe SWRules

Originally posted by machz1@Sep 19 2004, 06:54 PM
if your sled is brand new, barely run, then chances are your rings havent seated yet. these generally take a couple of tanks of fuel to get them broken in well.
346190



I agree also. You also need to make sure that the engine was fired very briefly just before checking compression. By firing briefly, you make sure that every time you check the compression, you are doing so with some constants.

Thanks guys. How much can I expect the compression to go uo after it is broken in?

you should gain 10pounds or so, not every sled will have identical compression even within the same model. :thumbsup:

My '02 800 checked in at about 152 PSI before the rings went on her.