Knock on wood but 18 hours and 400 miles on the 850 and it seems to be getting better every time I get the chance to ride it all hours and miles have been pretty easy one day with two up with kid on the back rest of hours were on a couples trip we do hopefully get up north in two weeks to really test it out lots of pull in the mid range and you can barely hear this thing run it is quiet, was worried about switching from the 137 Switchback to the 144 assault but so far so good handles like a dream and is smooth as heck all smiles so far runs about 108-111 when trails have some loose snow but if it gets real hard or get on some logging roads creeps up to 150-160 in a hurry