Super Jet Is this what they call pitting?What next

[munki63]

Everything was in it's place when I tore the motor apart, I paid a guy to rebuild my motor last time and never checked to see if the ports were unchamfered, I've sold the entire set-up including the crank (linked this thread with the sale) and everything I sold I got thanked for because of the wonderful condition everything was in, Including the crank, I know next to nothing when it comes to cranks but the guy that bought it was happy.

Could it have been a hair line crack in the cylinder wall? Because other then the pictures posted above there is nothing out of place or missing, and believe me I checked.

The only other thing I can think of is that motor ran away on me twice on the trailer last season?

I was running A/M Flame arresters with the over wears to help keep the water out

 

[OCD Solutions]

I don't want to go to the beginning and read everything but what compression were you running again?

ScottS was snagging rings on a home ported 760 last summer. It was running pretty decent for several gallons of fuel with a set of 38cc domes so he decided to drop in a set of 34's and snagged a ring. He chamfered the port some more and reassembled and ran it again. He made the better part of a day before he snagged a ring again. He didn't want to mess up his domes so this time he did a little more chamfer work and went back to the 38cc domes. After 3- 4 more tanks of fuel without issue, he went back to the 34cc domes and snagged a ring right away again.

Turns out the compression was too high and he was building too much heat at the exhaust port, overexpanding the ring into the port, eventually snagging it. Chamfering would not have helped but gapping his rings more could have.

I am wondering if your ski was not dialed in right on the edge of acceptable compression for your fuel and all it took was a particular hard day of riding, a bad batch of fuel with a low octane level or even a single WOT run just a little longer than usual? Any of that sound plausible?

Even though you built up completely different engine, you're still looking for closure on this aren't you?

 

[XJCrawler]

We did the porting ourselves before the season started and the motor ran away a few times last year. He could snagged a ring