Compression issues after rebuild??

[mdemco]

I have a rn I bought that had a worn out top end and porting I did not want. Before I tore it down it had about 115 psi of compression. I got a new cylinder, new low end porting, a fresh bore with pro-x pistons and put it back together with a b-pipe, new prop etc. The ski had a 62t top case on it if that matters.

I went and started breaking the ski in sunday and the thing rips, I have never been sore riding and I am still sore from sunday from holding on to it. I got it home, cleaned everything and di my usual storage routine and checked the compression for curiosities sake, it has 90 psi!!!

Could it have the wrong head? It is a new gauge I will check it with another but I cant figure out whats up!!! I am going to get a girdled head next week but any ideas???

 

[yamaslut]

compression tester calibrated???

 

[Shonuff]

Is it a good gauge?

 

[Matt_E]

If you're really running 90psi, your ski wouldn't "rip".

Get another gauge.

 

[Mike W]

It was hot as well. It should be cold when doing a compression test...From what I was advised anyway.

 

[mdemco]

Yeah the gauge is new and reads 140 on my buddies ski so all should be well there. And the ski was definitely cool when I tested it. I feel like when I was riding I felt the rings seat because the throttle response was noticeably better and the ski had a little more grunt. I cant imagine it could be 50-60 psi off, the head is supposedly milled but I have no idea what it came from, I would assume all the 701 heads are the same.