justin_o_guy2
Serious Thumper
   
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What happened?
Posts: 55279
East Texas, 1/2 dallas/la.
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If you're going that far, I'd consider the cylinder treatment. The machinist needs the piston, When I did the Raptor top end, piston replacement, bored,, the Yamaha rings had excessive end gap. The shop owner kept seeing me at the counter, walked up, the parts guy said These are what we use. I said The manual says end gap not to exceed,,x,, thousandths..
Owner told him, Find this guy a piston and rings that meet spec. And we eat the difference.
Wow, was I happy! IIRC, they took about a thirty dollar hickey.
Don't ignore the valves, at least turn the head upside down and level and dump gas in. If it's leaking, you'll see. Since you're jacking up the job they're going to be doing, maybe just take it to the shop and get the valves done. It's not really that pricey.
Just because a manufacturer puts rings in a box with a piston for a certain bore size doesn't mean you shouldn't measure the end gap..
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