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Hello, Forum, I have been reading this forum for a while but haven't written in until now. I have a 95 xcr 600 that I just aquired. Well I just melted it down 2nd time the middle cyl. Not real bad. But strange. the other cyls have piston wash that looks rich. And the piston that melted is eroded on the exhaust side of the piston not to the ring but close. I have wrenched on Atv's for a long time and melted several down trying to get that last bit of power you know lean is mean. But this thing runs great around the house but get out on a long snowy road and melt down city. When I first got it the air box was gutted and did not have any foam between the hood and the air box but it was jetted really fat. Since then the air box is back to stock with new foam between hood. jetting is two up from stock on the main and everything else is at stock settings. 10m weights with a blue spring in the primary with top rpm at 8900 secondary is a 40/38 with a blue spring set at #4. also it has psi pipes. My question is might I have a combination problem. could the timing be advanced with a tight secondary putting high load on the engine. Or am I just reading to much into this and it's just lean jetting.
 

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Does your airbox draw outside air or under hood air? I had a triple that had same problems on cold days but I was drawing air from under hood ( after market airbox ). Do all 3 carbs have same size jets or staggered? shane
 

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You could be drawing air from some type of leak on the center cylinder, carb boot or leaky gasket ect.... Call your pipe manuf. and get the jet specs for your machine. I had a 95 XLT Special and put 5,000 mi. on it, so I know your engine can handle it. There some little glich, you test for an air leak by spraying starter fluid or simular around the center carb boot. Besure to lift the rear end off the ground when you do this because if there is an air leak it idle up and might engage clutch. What color are all 3 plugs on the ends. shane
 

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Discussion Starter #5
I don't think an air leak is the problem. I am going to check, it's on the list. I can't seem to get any info from PSI for jetting. I do have to jetting guidelines for SLP pipes and i was only one size lean from their specs. They say you should jet up one size from their when using oxygenated fuel. Which is all we have here in MI. Have you heard of this? Also what's your take on staggered jetting. I think that is the way I am leaning toward.
 

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You might want to try running the center cylinder a size or two richer on the main. Although it's liquid cooled, some claim the center sees more heat which does make sense. I've read about many others having the same problems with triple piped triples.
 

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You mentioned the air box being gutted. I imediately thought of a forum entry I recently read where removing a shelf in the air box allowed a turbulance that resulted in lean center cyl. and melted pistons. I tried to find the append but ... Anyway, are you sure the inside of the airbox is restored to original?
Carbs clean?
Compare plug color. What do you see. If whitish in the middle, you are on the right track.
To be on the safe side start out with center carb clip in a lower slot (richer) Read the plugs and if they are all nice brown you are good to go. I think I am repeating what other have already said.
The best of luk to ya.
 
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