I did start running those fancy 105 plugs recently. Can a plug cause a piston to hole? The hole is dead center under the plug? I don't know if this is common, I have only seized from a lean condition never holed a piston.

It only made it 3 laps after I changed fuel and compression accordingly but, there was already a dent forming in the first piston which would have most certinly turned into a hole very soon. could the change in compression speed up the process from 250mi to 3 laps?

I also checked the trans oil and it was not over or under full. I did not check the water for over or under full.

I guess I will install new piston. Do a leak down test. Jet SUPER RICH and I may even install some E.G.T.'s and give it another go????????????

If I only make it three laps there will be an NSR in the trash bin at Grattan Race Way
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1995 A kit TZ 250
1994 Rothmans NSR 300sp SOLD
1998 RM 250 freestyle/motorcross
1998 Meathanol burning CR 500 AF super retard/motorcross/sand dunes/play bike