717 and 951 compression check

[turboIIaddict]

hello, just pulled my skis out for the year and started to do the general maint things for the season. did a compression test on both skis. the 951 is at 125 on both cyls, and the 717 is at 130 on the front cyl and 125 on the pto cyl. my question is, dose anyone know what number on these motors warrents a top half, also how far can the 2 cyls be off (717) before its a problem/needing more attention than just keeping an eye on it so to speak. - thanks guys.

 

[rotaxrule1]

I think the general rule of thumb for cylinder variance is around ten percent difference. So in your case, if they are more than like 13 psi different, there may be an issue.

Usually if something is seriously wrong though, you will know it. One cyl will be like 90 and the other 130 or whatever.

I am not sure if the other two engines are much different, but my 787 engines test at 155 ish. I think from what I have read here, 130 to 150 is acceptable.

 

[turboIIaddict]

alright appreciate the feedback just trying to make the most of my time this winter if need be on the motors

 

[rotaxrule1]

No prob. Now, if you wanted to do a rebuild on the top end, I am sure that would not hurt based on the readings being a bit lower. But if they still run good, I would just ride em and keep an eye on things. :cheers: