The later model shocks do not fit without a lot of machining because they have a fork mount at one end vs the earlier one which has an eye mount at both ends. All the early stock ones are crap, go after market. Fox, WP etc, I personally use a 90 model 40mm showa with a racetech gold valve but took some engineering to adapt the 86 mount onto it. However it does work awesome.
hey Doug, if you can put a Racetech valve in a 90 shock, that means they're rebuildable right? how involved is the machining? I'm pretty good friends with a bike shop that does quite a bit of machining and they have a 90 shock sitting around. I'm getting a new bike after this season so I don't want to really go aftermarket but if its not TOO hard, I'l probably go with the 90 shock.
I adapted the 86 4 position adjuster end to the later model by basicly making a giant helicoil insert and threading it into the 86 eye mount and then grinding a bit off the end of the 90 shock where the adjuster screws on. You have to pay attention when you are putting the end on that the inner oil hole lines up with the outer shaft hole. The rebound adjuster is 4 diff sized holes in the inner shaft and they line up against a fixed outer hole. Also if you are using it on a 750 instead of an 1100 its still a bit longer which means when you go to install it you have to compress the shock about a 1/4 inch to get the lower mounting bolt in but you have to back off the spring in order to compress the shock. Personally I really like it with the racetech gold valve you can really adjust it for setup and can play with the low speed compression as well but you have to take the shock apart to alter the shim stack. Once you have done the rebuild its a piece of cake to whip it apart and alter the shims. Also the gold valve comes with a video and once you do it its pretty simple. I have adjusted mine so that the rebound is at minimum and the compression is at minimum and the internal shim stack is doing all the work not the whimpy little orifices that the screw adjusters use which is true of any externally adjustable shock, the external adjusters are nice to tell you where to go with the shim stack when you are doing the initial setup, which is why personally I believe it is better than any expensive aftermarket shock.