I have a 2000 ZR 600 EFI with 1800 miles on it. Took out right hand cylinder(as you are sitting on sled). The top edge of the piston had chips broke off. The jug is all gouged up at exhaust port. While this sled was in the shop, I blew up a 2000 600 EFI Powder Special. Same cylinder did the same to the jug but this one cracked part of the top of piston off. What am I doing wrong? I am not a hard rider.

Post some pics. Close-ups of piston and cylinder. Be sure to note the exhaust direction.

It is the same engine on both sleds, slightly different clutching.

What about your fuel, maybe not enough octane, or water in it. Is the fuel old?

Did overheat light come on? Are these engines rebuilds?

Could be lots of things, post pics.

Also check out this web site and compare your pistons.

http://www.eric-gorr.com/tech/pistonguide.html

newf

SWRules

If you need a Piston Kit for it, I have a complete Weisco Kit Part # SK-1263. I am pretty sure this is the one you need for your sled. It comes complete with all Gaskets, new O-Rings, Pistons, Rings, Bearings, Etc.....

Some pics and more history would be good. My 550 did pretty mutch the same thing and was rebuilt 3 times on warranty. The problem that I found was that the lower ring locator pin would desintergrate causing the lower ring to turn and smack in the exaust port, destroying the cylinder and taking a good chunk of the piston crown off. I rebuilt it myself, changing the cylinder and buying 2 new pistons, SPI pistons the are built to the exact cat tolerances. (http://www.gammasales.com/welcome.html) will list a distributor in your area. You get the piston rings and pin in the kit, i recommend that you also change the bearing. I put over 2000 miles and no problems. After having posted my problem in this forum it was the opinion that this happened quite frequently with 550. I checked with several mechanics and they said the same and recommended SPI. This is what mine looked like.