I bought this shift lever to go on a vintage motorcycle. 10mm spline I believe and this definitely fits the spline. It also appears to be of good quality and I would fully expect to see roughly 15 yrs from this one as that was what I got out of the last one. Problem is if you are in a hurry and don't stop to think.........fitment XR50, IT80,125,175, YZ100,125, 400.
To get to the point a rider who pilots a XR50 is not gonna be the same age,size of the rider piloting the YZ400. It's pretty short. I cut the old one apart and the new one then welded my old shifter to the spline portion of the new one. Not the end of the world but seems odd IMS or someone somewhere hasn't noticed the fitment issue.