After sharing all the good, it's only fair I share the bad. I had the shee running with 330 mains which had it running alittle too rich but still great. I was now adding a pro-flow bracket with a foam filter to get rid of the stock filter and air box lid but before I was able to do my first plug chop I had already melted a piston, this was totally my fault knowing all too well that after modifing the air intake I should of gone up <U>at least</U> one jet size before attemping any plug chop or WOT run, but just the idea of originally running too rich gave me a false since of security which is a bad think on a 2 stroke.
Anyways the Shee will be back stronger and faster. This time with some new stuff I've been thinking of and researching which consists of alittle more port work to port match the cases to the jugs transfer tunnels and running power pistons which I might or might not bore out the windows a bit to match my intake ports I'll have to wait and see them first before I decide. I post pics of the melt down and also the port work I did and will be doing. Has anyone done anything similar to the new port work I'm thinking of doing?
I will be going up 3 jets sizes to 360 this time, lesson learned!!!!!

 

I had a similar situation where i kept burning pistons. my jetting seemed on, but i ended up needing race gas because compression was too high (185 lbs). What is your compression?

Just so you dont feel like the only one breaking.....i just did another rebuild, ran the race fuel i needed, and broke again.....I haven't torn apart yet, but i think it's either a piston skirt broke or the crank bearing. this also happened within 10 minutes. So in the last 3 motors, I've ridden the quad around the block 5 times.

By the way on this last rebuild i went with power pistons with bored windows. I never went with bored windows before, but the shop i bought the pistons from recommened it. If i tear it down and find a skirt broken, i think it must be from boring the windows. i think it may fracture the piston if not done right.

 

My compression is 150psi with +4 timing advance. So I should be safe with the 93 I've been running. I will be interested in finding out about what you find inside once go get in the motor. I couldn't wait to see what happened to mines so as soon as I got home it was apart only takes about 15 minutes and I was already washing my hands. I may just leave the pistons as they are because sometimes this grinding causes ultra-high frenquecy waves that may create micro-fractures.
This rebuild will cost me $206 for the Vito's PP's kit and $80 for the machine work, so at a total cost of $300 a rebuild I better not chance it with grinding away at these pistons unless I can get more info.

 

If it doesn't kill it, it makes it stronger.

 

trx250rob, how's yours coming along?

 

Are you sure it wasn't an air leak somewhere? Did it do damage to both pistons or only one side?

 

How do you like that 2 stroke now!

 

I got it running. Good thing I ordered new o-rings, I bit one when putting the head back on. Started on the first kick.

It's running like a dream, I gave it a heat cycle but couldn't ride it. I'm just waiting on the pivot bolt now.

I am going to replace a bunch of news bolts this weekend, I've been putting it off. I also have the new sprocket to put on.

I'm anxious to see how the suspension works, I did alot of tuning.

 

LOL....just joking...sorry too hear about the unfortunate happennings. 330 is pretty big.....you sure it's not an air leak somewhere? How did the machine idle?

 

That's bad, kicking a man when he is down.