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Discussion Starter · #1 ·
Hey guys!

I have a 1998 MXZ 670 that just started melting the PTO piston, near the intake ports. It crapped out after about 20 seconds of a high speed blast at WOT. I believe it was because I pulled the airbox off and was just using foam cone air filters. I didn't rejet richer and I bet that was the issue. At least that's what I've been learning online.

I towed it home and did a compression test to find one side was 135 and the other was barely 90. I pulled the heads to find the piston crown started to melt right where the top ring meets with that little index pin in the ring groove (ya know what I mean?). The cylinder wall is scored but isn't horrible... I've seen worse! So I know I gotta take it in for a bore. My issue is I don't have a manual and I need the patterns and torques for the 12 head bolts and the 8 clyinder bolts. I'd really appreciate it if someone could share that with me.

Thanks in advance!

Ed in St. Charles, IL
 

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Discussion Starter · #2 ·
I found it!
They are both 21 ft lbs. Thought I'd post it here for future searches.

Ed
 

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Discussion Starter · #4 ·
Thanks for that, SmallEngineGuy.

Would you happen to know what I can use instead of molylube? I read that I need to use a few drops of molylube on the wrist pin bearings during installation. In the past I'd usually just lube it with premix oil but I wonder why they'd call for molylube.

Thanks,
Ed
 
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