I picked up a stripped down DT2 thats been sitting outside for the last 20 something yrs. Guy said motor was locked. I got the jug off and surprisingly good shape origional bore, piston and rings in good shape. Shifter barely moves. Anybody know any tricks to free up the tranny? If i can get it to neutral i think i can get it to fire. Was thinking about filling up case with ATF or Marvels Mystery Oil and letting it sit awhile. Trying to avoid complete disassembly as of yet.

Hey Bart.
Is the motor still in the frame?
in gear?
Try rocking it back and forth, for an hour or longer.
Worked for the Greenie bike.

nah, took it out as im gonna use the frame on another working motor i have, but was glad to see that top end is good.

Very recent thread regarding the same problem and the issue turned out to be a stuck detent mechanism.

Undo the bolt on the left (looking from the top, as if you're riding the bike) underside of the engine and make sure that the cam stopper is nice and free in the hollow bolt and that it springs back when you push and release it.

The bolt on the other side of the engine underside is the gearbox oil drain plug.

Wonder why it got stuck up in the first place. Did it happen on the run or has it been left with the filler cap off & filled with water & rusted--unlikely though so far as transmission goes. If the detent plunger is ok you might need to pull the cover & grab the drum. At least pulling the plunger will let you know if oil in there or water--pull the main drain bung too of course.

I pulled both plugs and no fluids came out. So looking like it'll prolly need a teardown. I pulled the mag and stator assy and they were pretty corroded. Most of the gears behind the cover had surface rust so I dropped the bottom end in a bucket of Evaporust and it cleaned up pretty good.

Remove bolt containing parts 19-22 in diagram from this link www.partzilla.com/catalog/yamaha/motorcycle/1972/dt2/shifter-a

This was the issue from the previous thread. Very fast fix.