03-09 clutch basket/hub/pressure plate interchange

[Reedus]

Did a search across the board trying to find out if an 03 stock clutch setup will fit in an 08 YZ. From 04 on, it seems that part numbers are all the same. So the question is, did they simply just improve the design from 04+, or did they change something that makes it incompatible with a 2003

[grayracer513]

The only thing that will interchange directly with no problem is the friction plates.

The primary gear ratio was changed in '05, and the gear set clearnace was changed again in '08, so the basket/gear assembly will not work. The boss was upgraded in '06 and is interchangeable with all later years, but not the earlier ones.

The '07 and up have one fewer clutch plate than the '06 and earlier, and the pressure plate springs and steel plates are all different because of that. If you try to use a 9 plate clutch in place of the 8 plate the '08 was built with, the release arm will also need to be changed to an '06 unit. The outer, short push rod is the same back to '01, but the longer inner one is different.

Short answer is no, it won't work without a whole bunch of trouble, and you should plan to replace the '08 parts with the right stuff and be done with it.