Help! melted it down after 2 days of ownership

Those look like Wiseco pistons. I"d say that the piston expanded before the cylinder did, probably happend a few times before the final squeek. Just my $.02
 

I have used those pistons,they are spi with an anodized crown,it looks new thats why there is no carbon buildup,I would look for an oil pump problem or an over heat problem,they both look the same,it could also be detonation as this will cause the piston to become over heated and swell but I dont see any sign of it on the top,we are haveing problems here with fuel quality,mainly with skidoo's so far, I have to jet them up two sizes as they must be jetted on the edge from factory and it seems to cure the problem.
 
YAMAHIZAL700 said:
NO trust me I know all about it. I had a major backfire a few years ago when I owned my polaris ultra and it backfired so bad that the header pipe blew competely off the motor. my ears rang for a week. {no joke!} I had to drive it that way for over 300 miles back to truck so I know all about it. Also on my srx the I had old warn out springs like this guys is mentioning and drove it that way for a while. Other than being louder than it should have been and a loss in performance you could run it all day. ;)!
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Just did this myself this year, While riding my 2000 SRX, no backfire or anything. Just got loud. I thought I had just cracked a pipe and I rode it about 70 more miles and not taking it real easy ( about 50-70 mph) all the way. ended up I had a 3"x6" piece laying on the bellypan waiting to be welded back in. I agree with YAMAHIZAL700, as long as you don't pin it from a cold run you should have been ok, if the exhaust is the issue.
 
Take the `oil pump off and hook a drill to it,you normaly have to run it in reverse,tape the throttle open and see what comes out of the lines,just did a polaris switchback 700,it would not pump a drop,got a new pump and all is well.
 
sxr1000 said:
Take the `oil pump off and hook a drill to it,you normaly have to run it in reverse,tape the throttle open and see what comes out of the lines,just did a polaris switchback 700,it would not pump a drop,got a new pump and all is well.
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Thanks for he info that's kind of what I was thinking but I still think its a long shot because so far there seems to be no damage other than just the one cylinder and no signs of excessive heat
 
Ok this is what my experience tells me.
looking at the piston wash (ontop of the piston) its NOT running lean. if it would it would be all black and burned and the damage would me more concentrated on the exhaust side of the cylinder...
and looking at the pistonsides it has been running with no lube (oil) at all, makin the piston get hot and expand in the cylinder till it got stuck, my guess is also its wiseko pistons and they expands realy fast compared the the cylinder when getting hot/no oil

im not 100% telling this is the case, but i realy think it is.
 
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In case anyone is interested I talked to Wiesco today and its defiantly NOT one of their pistons. I'm still trying to get my friend to tear down the rest of the motor but he's working long hours right now. When I hear more from him I'll post it here
 
YAMAHIZAL700 said:
You need to do this yourself. its time to learn to fix stuff.
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Not my sled its my friends and the only reason I'm not helping him out is I'm 2 hours away learning to fix stuff at auto tech school right now ;)!
 
Well he finally pulled the other 2 heads. This is number 2
 

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Number 3 (pto side)

Anyone have a couple used cylinders for sale :o|

At least one cylinder looks usable. Anyway it looks like the mag side melted before and was replaced with an aftermarket piston but the other 2 are still original yamaha. Thinking oil problem now, oil pump cable was set a few mm less than spec. Maybe someone was trying to get more oil-flow :dunno:
 

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JoeyT said:
Just did this myself this year, While riding my 2000 SRX, no backfire or anything. Just got loud. I thought I had just cracked a pipe and I rode it about 70 more miles and not taking it real easy ( about 50-70 mph) all the way. ended up I had a 3"x6" piece laying on the bellypan waiting to be welded back in. I agree with YAMAHIZAL700, as long as you don't pin it from a cold run you should have been ok, if the exhaust is the issue.
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I will state my experience and you can draw your own conclusions rather than nit pick the issue. I had about a 1" hole rust through on the Ypipe of an 87' Exciter. I thought I would be alright driving it around the house for a few miles. Ended up melting that cyl down (it was crispy white). This was a ported motor. 97 600 XT I had the exhaust come loose up by Seney and lost 2 of the manifold bolts. I tried getting it back but ended up blowing that piston (also crispy white). 1970 SS396 one of the pipes lost the springs and fell off. The stock twin pipes are obnoxious as it is and I did not notice the noise. Melted that piston down crispy white with a nice hole in the exhaust side. Cooincidence on all three? I doubt it but you can draw your own conclusions ;)!
 
Thanks BBlueSRX I still believe the exhaust could have been the issue as well I am just less sure about it now
 
I think that alot of the damage in the one cylinder was from "managed to un-seize it after a few min of turning the primary back and forth. Limped it home"
THAT IS NOT A GOOD IDEA
 
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