2007 crossfire 1000 pto side piston failure.

Last run last year 1800 miles on sled stock except can. Lost pto side piston. Tore down and rebuilt top end. Broke in with 2 tanks of gas. Riding it yesterday across the lake and at pushed it and at 90mph lost pto side piston again after about 4 seconds wot. Pulled engine down and pto side has 4 corner scuffing like a cold sieze. Not lean beutiful burn and mag side looks perfect. Not sure where to go was wondering if anyone has ran into thermostat problems that could cause it to not build enough heat in the cylinder. New to arctic cat so if anyone has any info i would appreciate it. Thanks

Not sure how to get the pictures up it is telling me my pic are to high resolution but cant get my camera low enough

I changed the thermostat out and re did top end. Been out 4 rides now and really worked it and have not had any issues. So as weird as it seems the thermostat change so far has seemed to address the issue.