I just replaced my (stock) chain guide (the one that wraps around the swingarm) with a guide from a dealer, the guide I bought did not have a Yamaha part # on it like the one I took off which was the original one that came on the bike. After one day the new guide is almost worn through! I paid $29.00 for the damn thing and I feel really ripped off. The original one that came off my bike has been on since October when I got the bike and I ride almost every weekend and some days during the week I race around town for an hour or so. Are there any specific reasons why these guides wear prematurely? are there and *BETTER* than stock guides? Help?