got an genuine yz465H myself [in an it250k] but never had the misfortune [yet] to get into the clutch--but--you say everything measures up so run out of ideas before i start. Not possible that for some strange reason the pressure plate [where it splines onto the center] is bottoming out on the clutch center & not compressing the plates up? or 'just' compressing then lightly. Perhaps add another steel at the back or put two together anywhere across should work [or prove a point--fix or not fix]. Has freeplay on the clutch adjuster? [on pressure plate]--it'll have more after adding another steel of course. I imagine they have straight cut primary gears but back in my RT2 days with helical [or what ever they're called] primary gears which had a bit of play between bearing on the mainshaft behind the clutch & the circlip holding it into the case, so that when the power was on the angled gears would pull it all sideways & make it slip if the clutch adjustment was too close [not enough free play]. Thanks.
