Does anybody know what causes the larger diameter cylinder head studs to shear off? Last summer I took the heads off to replace 3 that had broken the previous season (2 on one cylinder and 1 in another), removed and replaced the broken ones, put it back together, and torqued everything to polaris specs. Now, 400 miles later, another one sheared off, this time INSIDE the crankcase! Iwas told by my dealer that if the head bolts arent re-torqued every 1000-2000 miles that they will shear off. Now that I've ruled out that diagnosis, I need to find out what is really causing this before I rebuild my motor again, just to have this happen again 400 dollars, hours and miles down the road. Note that the sled runs great, the spark plugs look perfect, the timing is dead on, I run 92 or 93 octane gas, the motor doesn't seem to vibrate excessively, and the motor mounts are fine. please help. :bash:

It sounds like the new studs you are putting in are not breaking, correct? If that is the case, I would go through and replace all of the studs. Your older ones are fatigued and more than likely getting over streched. When it comes to head bolts, or any other for that fact that needs to be torqued to a certian spec, I use once and throw away due to bolt strach and fatigue.

Did that answer your question???

Brian