I have three rides on my Primary Drive X ring chain installed on a 04 yz250... I don't have any fitment problems, Bought one hopeing it will last a bit longer than the stock one...( not long at all mind you) plus I don't mind maintenance as I am a maintenance manager for a bakery but to tell you the truth that chain maintenance was getting to be a pain in the butt with no pay off!. I was having to readjust after every ride....then I ran out of room . I don't know about the quality of other chains but this is the third ride on mine and I don't have to adjust it yet :) As stated before I noticed the xring is a bit stiffer that the non-ringed chains.. I bought mine one link too long so when I removed the link I thought it was cool they put a wax type of lube in there or so it seems ( I did not read through this thread so sorry if this was covered before) I figure one might see where this could cause some power loss... if any when the chain is cold, but after a few laps it should be warm enough to be some what fluid in there by that time so it would be a non issue.. Jeff.