I have a 1990 Yamaha "shifty fifty" dt50 that I got recently. The clutch cover was leaking oil so I bought a new gasket and went to change it out. While I was pulling the cover, the kick start shaft came out with it. I got it back into place and replaced the gasket and got everything put back together. I cranked the bike up and let it sit for a few minutes to see if there were any leaks. Nothing leaked so I decided to take it out for a ride. I shifted down into first and pulled out of the driveway but when I went to shift up to second the shifter was stuck solid. I have tried rocking it back and forth to try and get it to let loose but I do not know where to go from here. There is almost no play in the shifter, it's just stuck in place.