This summer I froze up my Bombardier sea-doo jetski motor, it is a twin 580 I didnt take it apart yet, but I plan on it very soon, I am afraid to look. Think it will be costly, it was at full throttle when it started to freeze, and I keep on it, thinking it was running out of gas, and then it slowly died out and wouldnt crank over ever again. I took the spark plug out, and it looked destroyed, melted it bad. I wonder what it looks like inside.

 

Take some pictures! if it looks worse than my banshee your bummin!

 

I did approx the same thing as you did. The oil of the power valves was boiling, and I have been brainless enough to not see that the hose was disconnected. I tried to get back home (I was on my way back when it stopped). It just lost its revv, and died. The morning after, I tried to start it...aaargh, the rope wouldn't move. That was enough to understand what was going on.
I'll post some pics on my site (see signature) so everyone can "laugh" of me

 

I really think you beat me, and by far!!! The rods seem to be OK, so does the crank, I haven't seen any debris inside the crankcase. It looks like a "basic" siezing. The pistons simply melted on the cylinder walls. I'll have to get them rechromed (or re-Nikasiled...dunno which one, thought it was Nikasil, but the dealer told me re-chrome...maybe he meant Nikasil...). Change pistonsis the minimum. Wiseco sells a piston kit for 225$us (both pistons, rings axles, pins...). That's way cheaper than original (150$can 1 piston), and probably just as good.
I'll change them as soon as the dealer opens (tuesday!!!). 1 foot of fresh powder...and mo sled!!! Life is cruel
I'll email you the pics, but you can't see much, maybe I'll take some newer with everything apart.

 

Don't use Wiseco pistons in a two-stroke. I was in the same boat that you are in when i seized one of my pistons on my MXZ670. I was also thinking of getting a Wiseco kit because of the price. I did alot of calling around and talked to a few dealers and people that race sleds and most of the guys told me to stay away from the Wiseco's and that the stock pistons are the best you can get(at least for Ski-Doos anyway). The reason is that the Wiseco's are forged and the stockers aren't. With the forged pistons, they expand more when they heat up compared to stockers. So that means you have to run like a .010 cylinder to piston skirt clearance. When you start up you motor when it is cold, you will get quite a bit of piston slap because of the big gap. I went with the stockers, more money, but i haven't had any problems.

 

Grim, your statement is some what true. While the Wisco is a forged piston, it's not like your telling it. On a new top end install with a wisco, here's the steps. Run it 15min at nothing more then 1/2 throttle and vary the engine speed. Then shut down and let the engine completely cool down. That's it, your done. But I always like to give it one more rotation as notied above. This unlike a stock piston which takes a tank full of gas(about 4 or 5 hrs). Wisco is a better piston over stock, on atleast any of my bikes I have owned. I'm in the process of boring my 00 scram .10 w/ a wisco. Just my 2 cents worth.

 

So what piston is the best (durability) I dont care it it gives me the most H.P. or anything I just want the one that is going to last the longest. What would you guys suggest?

 

stock!!!!

 

Go stock(ART) or Pro-X. They are cast and do not expand fast like a forged Wiseco.
ERIC

 

choosing a piston is like choosing a barber..pick what you like.