Has anybody had any problems in the past shifting into 3rd gear on an 82 250R? Is it common, and is it expensive?

 

Most common problem with trannys are bent shifting forks. The forks aren't expensive, it's that you have to do a split-case to repair them.
Also, it is common for older ATC 250R's to lose third gear completely. Again, it's not the gear that is expensive, it's the splitting of the case to repair it.
Can you shift past it to 4th?

I didn't know Honda made a 250R in '82.

 

They also made one in 81.