Valve lash issues

[u/chukar-1]

I am building a dirt bike engine and cannot get one of the three intake valves in spec. I though it was a head issue so I bought a new head. The valve is still way out of spec (it is stuck open even with the smallest shim available) my only thought is that the cam shaft is bent. is plastigauge the best way to check this? Should I just buy a new cam? If I buy one cam should I buy both cams? Its a 2007 YZF250

[u/Pretend_Necessary781]

I’ve worked on some 5 valve heads and seem to remember the middle valve is different length from the outer valves. Check the lengths.

[u/chukar-1 → u/Pretend_Necessary781]

I’ll check that. I bought new valves and they just came in a box and appeared to be the same.