I just installed had a 1 1/2"x121", "intense" camoplast track put on my 2003 800 mxz rev. The sled was not ordered with the optional 1 3/4" track it just came with the standard 1". I haven't ridden it once yet since there is no snow here yet :( :( . I have only run it on a stand in the garage but from running it and listening to it you can definitely here some the lugs hitting something... I know that the 2003's ordered with the 1 3/4" came with the bulkhead modified for the larger lugs, right from the factory, I wonder if this same thing needs to be done to mine??? Also should i change the gearing so that i minimize top speed loss as much as possible with the bigger track or should i go with more acceleration or should i find a nice medium??? Anyone have any experience with these problems or help??

where is it hitting? that should be easy enough to find out.

ok...first of all there are no modifications needed to fit a 1.5" track under your sled unless maybe under the beaver tail if anywhere.

Make sure your track is tight enough before jumping to conclusions and try spinning it slowly and watching for where its hitting.