thanks guys for the info,my buddy who is a bike mechanic has run into so many 750s with broken case due to chain breakage,i saw one myself last week he has one in storage ,what a shame,who sell replacement cases?,,,so its good to go with a 17/48 for city driving and occasional freeway?,don't plan on alot of freeway, i saw some DID chains on ebay but the application for the chain was only up to the 1977 model 750,wonder why