I have a Gen1 Busa & the teeth on the vortex rear sprocket broke off when I dumped it. I have gone to a 43 from a 42 on the rear (since that is the highest I can go with a 112link chain) and I am keeping the front sprocket stock. My dilemma is, I am told that if the rear sprocket is messed up, then the front one probably is too, and my chain is probably stretched. Is this true ???? I took off the front cover but the sprocket looks fine, should it be changed just because I am changing the rear ? Do I really need a new chain ?? Heeellllppp :{ .... I can do the work I just want to know what is best for my Baby Busa..