Sos!!!!

When I was putting my engine back together today I got to the point where I was about to torque down the cylinder bolts when I decided to check to make sure the piston moved freely up and down through the cylinder wall. When I started to turn the flywheel with the rachet, everything seemed to be ok and then it locked up. I thought maybe it got stuck on the cam chain or something so i turn the other way and rotate almost a full cycle and boom happens again?!? so both ways before a full cycle the piston stops. I don't want to force it through and I know many of you have torn your motors down, is this a normal occurance. Maybe its the starter? Should I be able to do a full rotation using the flywheel? I ended up taking the wall and piston off just to make sure they had nothing to do with the binding. So with just the crank and rod staring me in the face its binding just before full turn. I checked to see if it was in gear as well before you knuckleheads start chiming in. And even if it was it wouldn't rotate that much.

Good thing you checked!

I assume this is the XR650L in your signature?

Did you split the cases?

If you did I would check the timing of the counter weight. It will hit the crank if not aligned properly.

Where in the stroke does the piston stop? Top, bottom, somewhere in the middle?

the cases weren't split this is just a top end job. I think it was on the way down both ways....its in the same spot whether rotating cw or ccw

One thing that happens is putting the piston in backwards, and the exhaust valve reliefs are too small for the intake valves. Don't ask me how I know this. A friend...yes...a friend did this once.

yeah but im not even to that point! besides the piston has an arrow on it pointing forward:P this problem is in the crank has nothing to do with the top end at all.... this is a simple top end job the engine wasn't even turned over when the head was taken off.

You checked to see that the cam chain isn't coiled and bundled on the crankshaft gear? It sounds like you checked but it id hard to tell so I'll just ask the daq's.

yeah but im not even to that point! besides the piston has an arrow on it pointing forward:P this problem is in the crank has nothing to do with the top end at all.... this is a simple top end job the engine wasn't even turned over when the head was taken off.

so u don't even have the rockers/valve cover on yet...

sounds like interference with the counterbalancer as mentioned...wut else cud it be :worthy:

since i've not "been there" i'll leave it to those who have :busted:

u'll get er figured out :lol:

:banghead:

P.S. ur not missing any tools or rags??? :lol:

P.S.S. i've been there... :lol:

Well, you're just going to have to retrace your installation steps.

Unfortunately...

theres no installation steps the jug is off the crank is binding... nothing was done to the tranny it wasn't turned over... the cam chain isn't even on the sprocket

It should spin freely. There is something obstructing rotation.

Its very possible something may have fallen into the case. Like said.

Did you have the left or right case covers off?

Are you sure there is not a bolt or socket down in the crank case?

If the chain were all bound up it would not rotate as far as you are describing.

You said the piston is off and it still binds so that eliminates piston to crank clearance.

Does the crank come to a smooth soft stop like something is getting tight or is it a hard stop like the crank is hitting something?

Also is the big end of the rod going towards the front or rear of the bike when it stops rotating?

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