Hey All. I bought this 04 660 today. The guy I got it from told me it had a new piston and rings installed about 100 miles ago. I have the wiseco topend kit box so I belive him. (done at dealer)
Anyway, He was riding at wot on a dirt road when it lost compression and died on him.

He told me that he filled the rig with 87 octane fuel shortly before this happened. He had been running 91 up to this point without issues.

My question or questions are this:

What damage could the lower octane fuel do? Rings? Valves? I run 87 in my quads all the time and have no problems.

The motor will turn over very well but will not start. No suction on the intake = no compression/no fuel to motor Right?

Could the rings be cooked?  Or could I have a Valve issue? #27 pipe, (upper left corner) is not connected to anything. This looks to me like a vacum line, is it? where does it go? Should it be plugged or what?

Reguardless, I guess the topend comes apart anyway. I just want to be sure I am not overlooking something before I tear into it.

Any help would be appreciated.

Thanks in advance.
[font=Comic Sans MS:42da680d68] [/font:42da680d68]