Just to clarify it is not a torx and you should strip it down to make it easier and to clean the crap that is in the spring. By the way the center bolt should be hollow. I would not use loctite.
No, the center cases have to be opened. Top ends do not vibrate. Since you had a loose needle bearing, I would do rod and mains. The bike is 44 years old. The only reason I would take the time to do it is it could go another 40.
Yes you have to take the clutch apart to get to the center bolt that holds it on. After the bolt is removed it just comes straight out, sometimes not easily.
First give the bike a good clean, chances are you are going to split the cases. The video of adjusting the cam on the spring is exactly where to go next. If you are lucky the top hat just sheared the little tab in the end of the shift shaft. Usually it ends up being a new shift shaft. Lucky you.
You should stay off topics that have nothing to do with your old engine. Everything about a ty 250 mono is different from your old bike. We are talking about an engine that came out in 1984, not 1974. And by the way Dannyboi the TY250R had a standard bore of 68. So you would want at least a 68.25.
You should have the piston before it is bored. This seems the easiest solution unless you can find a mono 250 piston 1st or second over. I have seen pistons, but no rings.
I had the same problem the last time I did my seals about 45 days ago. Try about 340cc and call it good till you have time to fix it. I might get around to it myself this coming weekend
A hot saw blade vs the plastic insert. The question is will the inserts come off without damaging them? Update, I forgot the insert is actually held in place by screws.
