97 Vmax 600XT twin cylinder piston failures

3

3yamis

New member
Joined
Feb 27, 2008
Messages
15
Location
Peterborough Ontario
I have had two pistons fail in this sled due to the ring groove pin falling out and the ring turning and getting caught in the ex. port. It failed both times on the flywheel side. Once the original piston at 7000km and then now a wisco at 14000km. The clutch side has never failed; it does have a wisco as well. Yamaha has updated their piston and new it was a problem but I did not expect to have the same issue with wisco. Not sure what piston to use now; I do not want to buy another cylinder.
 
Hmmm boy that is strange...maybe just bad luck :dunno:? hard to say,
lota members re built with oem pistons and never looked back, i say go
with OEM again,any new piston will be updated..better.
 
Happened to mine 3 years ago. ~7500 miles. Same cylinder as both of your failures. Odd. What is more unusual all the Yamaha twins I have seen failures on personally have been the right cylinder. Besides the seals being different the only difference I can tell is the right cylinder has the fuel pump signal line plumbed in the back of it.

So If I were you. I would get another cylinder. 2 complete pistons and all the gaskets you need. Then take a real close look at everything on the right side of that motor. You might not find anything but for $400-$500 in parts I would go over it with a fine tooth comb before I put it back together again.

4400 miles between rebuilds is a bit close. Maybe when you get to 20000 km you could start thinking about a refresh again. All it will cost ya is a set of gaskets and a quart of antifreeze.
 
There were 3 yammie pistons for that motor, the original 97's, the updated 97's and the last service replacement pistons, which are the good ones. If you want to fix it once and for all, put only the lastest Yammie parts in it. The part number will end in AO 10. That was the service piston made out of the same material as srx and viper pistons. They are more expensive, but you will only do it one time. I have cylinders, heads and pistons if you need them.

You sure the ring just turned or did it turn after you detonated the piston, the common failure of the original piston was the ring land breaking and then the ring coming out.
 
looks like you need a new cylinder regardless, along with 2 new pistons.

Wisecos are good pistons. but yami had issues on the 600 twin pistons, originally.

price the new yami pistons out vs the wisecos, then determine which you want.


I have used wiseco's on several polaris with no issues, and I have used them on doo's as well, and while I think i Have yamaha's in my 600 twin yamaha, I can't be sure, since I have not taken the motor apart since I have not had to. We bought it used this fall, so I have no clue, other than that it has round pistons in it that hold good compression.
 
My brother had the same problem with his sxr 500 it seem to be common on the twins. He ordered a cylinder ,piston, and gaskets from cv tech http://www.cvtech-aab.com/contenu/index_ang.cfm the cylinders are $ 293cdn also ask what piston to use they recomended a certain piston to my brother to use with the yamaha because certain aftermarket pistons have to tight tolerances and are not reliable. I can't rember what one they recomended though. They also replate cylinders and have one year warranty.
 
Ok; I could imagine the 500's having the same issue. Yes I got my cylinder today from Nika Tech in Que. This is the second one I have bought. Same one failed again. They just recommended a Kimpex piston; wow! Wisco was willing to help me out with a new piston ect for $85; but they had no stock; strange eh? Thanks for your help.
 
Oh yah Wisco are much cheaper than yamaha pistons; in price and quality; lol. Never had piston issues with a sled before; just this one. Those motors have low compression stock unless you split the head gasket ect.
 
Wow Mr 800 you are the wealth of knowledge I have been looking for; Thanks. The new stock piston is for sure the best bet; just more money but savings in the long run. Too bad Yamaha did not cover this under warr. I still have a original piston; I think it is but could also be the second edition. My head should clean up fine like it did last time. I purchased a refinished cylinder from the same guy in Que as last time. I am sure the ring land could have broke first; the problem is I had to drive it for a couple hours after so it was harder to tell. It was almost working normally by the end of the day and when the temp dropped; no one would have believed me it failed.
Thanks again; maybe I can learn more from you.
 
Reply to daman

daman said:
Yes..re piston both side's!

you got them wisco's in there, your cyl's still stock plated??
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I will buy the yamaha piston before I put many more miles on it. I will leave the good clutch side wisco in there for the rest of this year. Clutch cyl. original; flywheel side replace twice now.; ouch.
 
Mr Fuzz; thanks for your help. You might think it was a timing thing or vib. problem; yamaha should answer us. Mine gets ridden pretty hard so I would say both pistons that failed lasted 7000km approx. I got it when it was 3 years old with 4000km so who knows before then. I would love to keep it but I want an RX-1 for next season and I think I should keep my 800. Two sleds are enough for me to store. I would love to see that sled go 20 000km or the original crank.
 
Well keep it oiled and run good gas to keep away detonation and make sure you don't over rev it and 20000 km is not a big deal.

I have Kimpex pistons in mine. When I smoked it I was a bit short on cash (Tax season and all) so that was all I could afford since the cylinder was $225, $75 for gaskets and odds and ends about all I could scrape together was another $120 for the piston set. Took 3 weeks to come up with that much extra money. Now I think I would go with the Yamaha ones but so far I can say the Kimpex pistons are just fine.
 
3yamis said:
Oh yah Wisco are much cheaper than yamaha pistons; in price and quality; lol. Never had piston issues with a sled before; just this one. Those motors have low compression stock unless you split the head gasket ect.
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quality wise they are not cheaper, just price wise.

are the stockers cast, like I think, or are they forged as well?
 
3yamis said:
I will buy the yamaha piston before I put many more miles on it. I will leave the good clutch side wisco in there for the rest of this year. Clutch cyl. original; flywheel side replace twice now.; ouch.
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I would never run 2 differnt piston brands in anything with more than 1 cylinder (;))

if the yami is cast, the wiseco is forged, and I guarantee the wiseco weighs less due to being forged. different weight pistons will create some not so good balancing issues.
 
2 Different pistons

horkn said:
I would never run 2 differnt piston brands in anything with more than 1 cylinder (;))

if the yami is cast, the wiseco is forged, and I guarantee the wiseco weighs less due to being forged. different weight pistons will create some not so good balancing issues.
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Rule of thumb; as long as they are within 20% of each other. They are according to my scale. Stock original piston is about 15 grams heavier. It is running fine so far. If I keep it I will put in the new Yami pistons. Seems smoother than ever now. lol.
 
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