1998 srx 600 pistons

[jamuss77]

I have just replaced all 3 pistons on my 1998 srx 600. I had issues with it not idling but that was cured by dissassembling the carbs and doing a complete cleaning. I am curious to know why the pistons melted the way they did. All of them melted on the exhaust side. I used premium gas whenever possible but sometimes I used 87 octane with octane booster. On the day the pistons melted it was 0 degrees outside. I had stock jets and was not riding hard. I have checked for air leaks by spraying gas around the carb boots and crank seal with no change in rpm. Can anyone tell my why this happened? I don't want this to happen again!

Here are pics of 2 of the pistons I removed from my sled.

 

[no1chevyboy]

could have been ran hot at one time, is this sled new to you? in pics it looks like the one on the right burn first then stoped ,the one on the left looks a little fresher, lots of blow bye though on both, could have ran lean at one time too.

 

[jamuss77]

could have been ran hot at one time, is this sled new to you? in pics it looks like the one on the right burn first then stoped ,the one on the left looks a little fresher, lots of blow bye though on both, could have ran lean at one time too.

It was new to me last year. I was thinking it was like this when I got it or at least partially. The previous owner had rich jets in it when i got it, it was using lots of fuel so I jetted down to stock jets and less than 100 miles later is when I had issues. I put the rich jets back in now that I replaced the pistons. Should I leave them in or should I go back to stock?

 

[no1chevyboy]

well really, if everything is ok,no seal leaks,no air box mod,no exhaust mods,everything stock, stock jetting should be fine its usually a tad fat from the factory you will have to do some plug readings at different throttle positions to see if all looks good, and check for air leaks

 

[mopar1rules]

is your airbox gutted or modded?