v-max piston damage need diagnosis pics included

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vmaxrider

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Mar 10, 2004
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i rode 1200 awesome miles this year but on the last ride of the year i could tell i was loosing compression in one cylinder. i tore it down and one piston looked perfect! it was like new. the other looks like it could have snagged a ring or something. im not quite sure what exactly was the cause of the damage. i could tell by wash on the good piston that i was running pretty rich. it wasnt oil related either. i thought that it could have been a slight meltdown, but its only on the one edge. the damage is partially over the exhaust port. im thinking the ring snagged on the corner of the exhaust port and tore everything up. anyone have any ideas? what should i do when i reassemble the top end to avoid this in the future?
 

I have seen this so often this winter that it makes me sick . I think the rings stick and then there is blow by ,over time it burns the piston top
at the exhaust port when it gets to thin the ring breaks and thats it . Did it ruin the pot .You didn't say what it is out of .It looks like a 97 600 twin .
so far mine has had five pistons and two pots . If the pot is ok just replace the piston and rings .Make sure the carb jets are all open and there are no vacuum leaks and away you go . If this is the first time open
you may as well do both pistons cause the other one will go next year .
 
what do you mean by pot? my sled is actually a 1996. i bought it used with 3600 miles on it. this is something that i have never had happen to any of my machines. its like a snagged a ring and the corner of the piston melted. i have seen snagged rings and the piston didnt appear to be melted. the port doesnt look too bad but i have some deep gouges in the cylinder. can i just resleeve the cylinder on a '96 or what do i need to do to repair it. it doesnt look like there is an actual sleeve in the cylinder and the scratches are too deep to bore. i had to ride about 50 miles after the sled starting acting sluggish to get home.....had no choice :x
 
You will have to get the cylinder renikasiled you can probably get a rebuilt one from a Yamaha dealer ,Last time I did mine I found a used one on the parts forum . The cylinder is the pot .
 
where is a good place to get a cylinder renikasiled? could you just fill the deep gouges in the cylinder with a weld and then bore the cylinder smooth?
 
I had this happen on my 97 last year. I went through millenium technologies to get the cylinder redone. They had a really quick turn around and did an excellent job. There's some other companies that do it too, just can't remember what ones. There's usually adds in the mags.
 
Millenium is a good choise also check with US Chrome in Chicago. I called them both when I smoked a piston just like you did. US Chrome will weld the gouge and renickasil the cylinder or if they have one on there shelf they will ship a rebuilt ( they look brand new ) cylinder out that day. Both places charge $ 225 for exchange but US Chrome said if all it needs is a renickasil it would be around $ 110 complete. Good luck! :D
 
$225 to get the cylinder redone?! how much is it for a brand new one. it cant be much more. i think i might keep an eye out on e-bay. i got till next winter to fix it.
 
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