I recently did a top end at 180 hrs, IMO I should have pulled it apart at 150, it appears the TPIs are a little harder on the top end then the earlier premix motors, all else being the same, same oil, same terrain etc... I suspect the difference is in the oil inj vs premix. Everything was at max spec or a over (rings) but surprisingly compression was still pretty close to where it was when the head was installed, only about 4 psi drop. Overall no surprises and it looked good, minimal blowby. I'll take the wear rate into consideration next time around.It's been a great bike and I've definitely gotten my money's worth. The 660 hours are full of good memories. Many adventures, probably about 40 races, and the bike hasn't ever let me down.
The only time the bike didn't get me back to the van was when I melted the piston and that was completely user related, not the bike's fault.
I might get a fresh 300 this year but I'll be keeping this one.
I've noticed the same. Compared with a carbureted 300 the rings seem to wear out approximately 10-15 % earlier.I recently did a top end at 180 hrs, IMO I should have pulled it apart at 150, it appears the TPIs are a little harder on the top end then the earlier premix motors, all else being the same, same oil, same terrain etc... I suspect the difference is in the oil inj vs premix. Everything was at max spec or a over (rings) but surprisingly compression was still pretty close to where it was when the head was installed, only about 4 psi drop. Overall no surprises and it looked good, minimal blowby. I'll take the wear rate into consideration next time around.