Anybody know who sells them? I had one basically split in half on me. Hammered the head and piston crown pretty good, and bent the intake valve stem. A nice round disk of the prechamber insert is pounded(welded?) on the the piston head - I haven't tried to remove it yet other than by finger. I had rebuilt this engine two years and about 12k ago. GRRR. At least the cylinder wall looks good from my quick inspection the other day. Looks like new head time, and a piston(at least I know what pistons are in there now - so I'm hoping I can get one that matches).