Hello all, im having a weird leak on the left half of my crankcase that I just cant find a seal for or anything I can replace to stop the leak, im at the point of using jb weld to seal it but figured id ask here first. The leak is coming from right between the shifter and drive sprocket, there is this little protruding spot on the case that looks like it should have a seal or something on it but nothings there and it just leaks trans oil out. Ill try to upload an image but other then that I don't know how to describe it better. Thanks all

Bike model ?

74 dt250a

I think that model had at least one shift fork support shaft that was through-drilled through the case and sealed with a cap.  

I know the shift drum was too.  

See if part #19 in this diagram makes sense.

www.partzilla.com/catalog/yamaha/motorcy...974/dt250a/shifter-1

I found a pic.  It's basically a small "freeze plug". A good auto parts store should have one. 

Yes! that is exactly what it is, thank you all very much for the help. I am still new to motorcycles in general so this is very helpful. I just replaced the shifter seal and installed new clutch plates and springs so hopefully i can ride again soon. Thanks again all