Motorcycle Repair: !981 sturgis, gears, good luck

Question
Hi
I own a 1981 sturgis and i have a 4 speed stock transmission on it and it keeps on locking up on me i took it out to the shop and had it fixed and now today it locks up on me again the shop put a shim in the transmission and i guess that didnt work and i was wondering why it keeps on locking up Please help me out
Thanks
Jeffrey Hoachlander

Answer
If you are locking up in two gears, then you are having a spacing problem with the gears. the trans would have to be pulled and all the gears spacing needs to be checked. You might have a bent shifter fork also, which would cause that problem
Good luck and happy riding
Mike