I recently purchased a 2000 KX250 to restore. I bought it with a bad engine. I started by sending the cylinder to Millennium to be replated and fitted to the new piston I had. When I went to assemble the engine, I discovered that the inner clutch cover was warped. I bought a replacement off of eBay and it was bad as well. I read in a few places that a '98/'99 would work as well. I found a nice one on eBay for a good price and purchased it. Well....it's somewhat true that the inner clutch covers are interchangeable.You can swap the newer cover onto the older engine, but not the other way around. The newer engine uses a slightly larger governor, so a portion of the inner clutch cover is been milled out a bit larger. The larger governor won't fit into the smaller area on the '98/'99 covers.
With that said, I've found several post about swapping governor assemblies in order to change the characteristics of the power valve. I couldn't find much info on my vintage of bike though. It was mainly for the '03/'04 bikes.
Should I search for another inner clutch cover that's for my bike and use the correct governor assembly or is there something to be gained by using the older inner clutch cover and matching governor assembly? Just curious which part to buy next. I'm ready to button up this project!