[ck.mecha]

Im not making any statements about how these differences affect ride, but more posting this for posterity and in case anyone ever is wondering if they can use 300 parts on the 250.

I recently had a couple sets of both 250 and 300 forks apart to pick the best condition parts & put together a set for the coming race season.

The first main difference you will note is on the inner fork tubes. The ones on the left are 250R, the center is 300, and the right is an aftermarket unit for the 300.

Other than this pressed in piece looking like a forged/cast piece in the 300, the inner fork tubes are essentially dimensionally identical and can be interchanged. I noticed on all the fork tubes that the holes in this pressed in piece was never indexed with the holes on the inner fork tube. Obviously either Kawasaki cares nothing about this alignment or it is unimportant.

The major differences were in the damper rod and guide. The guide is taller and the compression damping holes are placed higher on the 300. I didnt take a picture of it, but the rebound damping hole on the 300 is also slightly larger than the 250R. The ID of the 300 damper rod is also about 0.25mm larger. Despite these differences, they are interchangeable provided you replace the damper and guide as a set.

I hope this information is of help to someone.

PS. All these inner tubes bend extremely easily, I took apart 4 sets of forks and all 8 OEM tubes were at least 20 thou out. I would not recommend buying used 250 or 300 forks with the idea to slap them on and run them as is