Ok, I have an 86 250r and reassembled the top end tonight, I had a terrible time getting the piston back into the cylinder, but finally got it, now it wont go all the way to TDC (top dead center). It seems to be getting stuck on the exhaust port? Is there any way that it could be in tehre sideways and that be causing it?
Thanks

 

Well if you had some much trouble putting it back on, you might of damaged one of the rings. Try to take the cylinder again and check the bore ( the wall) if you see any scratches, is one of the rings. You are gonna need to purchase new ones. Dont even try fix them, you cant. Ive tried.
Laters

 

Did you line up your rings with the little "****" that is there? or arrow?

 

That was the problem, I wasnt aware there was a **** or whatever and wasnt lining them up right.

Got it now, thanks!

 

nice.... bet that sucker was hard to get in huh??! I figured Id throw this in, dont know if you did, but never reuse a circlip.. did the rings get messed up? or the port??

 

No, it didnt mess up the rings or the port, I never really tried to push it over real hard, I left the head off of it and tried to go ahead and push it over with teh kickstart to make sure it was all working right and when it stopped so did I. I have been really careful to make sure I dont mess this thing up!
And yeah, it was a CHORE to get that thing in there! It was a combo of a ring compressor, a rubber mallot, 2 guys and a lot of swearing!

 

The two ring end gaps should be towards the intake side. There are two pins, one in each ring groove that keeps the ring from spinning and hanging up on a transfer port.

There should an arrow or other mark denoting which way the piston goes in the bore, the arrow will point towards the exh port.

Shouldn't have to get too crazy to get the piston in the bore. Squeeze the rings with one hand, and then get one side of the sleever BARELY started and then rock the cylinder to get the other side started as well. Get the piston up into the bore partially, about the hgt. of the intake port. Gently try to spin(slightly) the cylinder on the piston, VERY GENTLY, you're wanting to watch the rings to see that they are firmly seated in the grooves and the end gaps are in the right place. Then continue running the cylinder all the way down.