New this this site and just getting into the twin shock bikes. I have got a 76 250c. It has stuck in first gear and can not shift out of gear. The clutch still works and can be ridden but will not shift. Any ideas?? I expect to have to pull motor and split the cases. Unless anyone has any other options that I don't know about. Any help would be greatly appreicated

Need more info.

You have not said if the shift shaft is frozen, or still moves. If the shifter shaft still moves freely through an arc, it is likely to be a spring broken or popped off behind the clutch basket (no need to split the cases). If it doesn't return to mid position itself after being moved, also likely to be a spring issue behind the clutch

If the shifter shaft is frozen it might be bent, or maybe something else - more info needed.

Is there any evidence of the shift shaft being out of position axially, or having had an impact? Is the circlip still in place where the shift shaft enters the gearbox on the LH end?

Welcome aboard,congrats on getting a TY. I wouldn't rush to remove the engine and split the cases,drop the bash plate and remove the clutch cover and clutch.Have a good look at the selector shaft end and linkage there,its most likely that's where the fault is.They are a tough motor,doubt there is much wrong with it.

As said, it's more likely to be where the shift shaft engages with the selector drum behind the clutch drum

Thanks to all the replies. The shifter is frozen does not move up or down. Originally it was stuck in 4th but I got it to shift down and up for a min then it has gotten stuck in 1st gear. I have taken nothing apart as of yet as I had to go to work. Hoping to get it apart this weekend just looking for ideas where to start.