We went out for a run today. i put on about 30 miles. we where going down a ditch about four miles from home and my machine stopped. the main shaft kept spinning. I did not move. We went and got it brang it back to the shop and put it in. I did not rip it apart because the game was going to start. This is the second chain i have broken in about 500 miles. Is this common. Does this happen on the 900s or is this just a fluke. I checked the chain tension about 200 miles ago and it was fine. The oil was also good. These parts where from hi performance, they were also the stock gearing. If my gears are shot what is a goo replacement. Thanks. p . s.

No it's not at all common, 9300 miles on my last sled ('02 zr-800 cce) with no issue, just over 2200 miles on my current 800 and no problems.
Have you checked for gear run out (are they running true), is the driveshaft bearing on the LH side broken, is the driveshaft bent or have you been running the chain far too tight? Lots to check but it's gotta be one of the above.

Rick.

i had my brother inalw who races for cat check it out he thought it all looked fine. just too much hp he tought. maybe my chain was looser then i thought and it slapped and i blew it. back to running tonight.

Something is not right. Either something is bent or the gears are not inline with each other, or maybe a bad gear.