hey yall new to the group been riding old Yamahas since I was a kid so I bought a few lately and my favorite of the bunch stopped running. I'm no bike mechanic but after draining the wrong side I guess I drained the gear oil and ran it dry? now it wont shift and I need it rebuilt. besides that long story what are my options if I wanted to swap a brand new engine into the bike. the frame I have is a 1973 DT with a RT1 360 and in great shape so I dont want it to goto waste! any help I'd appreciate! like I said I dont know much but I'm a quick learner! thanks

When you took the shifter detent bolt out (instead of the drain bolt), the spring and detent probably dropped out too, and if you didn't install those back in, then it won't shift right. Look in the bottom of the drain pan you used, the pieces are probably there!

Welcome. Just wondering why you drained it--& if it was the transmission did you leave it dry & ride it until it stopped shifting. Or am i misunderstanding. Hope all is not lost. What 'apex' says above is good thinking & hope he's correct. If all 'is' lost then any 250 or 360 from "70 to "73 will fit. Well, any 250 from "68 if that was your only option. Gearbox 'call it trans', holds 1 liter of oil including the clutch where the filler hole is. Takes a little while for it to settle right through so don't be worried if the dipstick shows it over the mark. That's providing you drained it fully.