1980 XS400 engine not turning

Karim

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So I bought a 1980 xs 400 that was not running the kick starter would not move and the starter wouldn’t turn the engine over took the spark plugs off inspected with the scope no signs of interference got the engine to turn with a ratchet was not easy at the beginning but got it going smooth I drained the oil and found a piece of Badly wrinkled shim-metal like extremely thin gauge

Changed the oil and filters started the engine it turned over twice then seized again.
Still no interference but the seizing looks like it’s coming from the transmission. What do you guys think I should do or what do I need to takeoff to access the internal gears of the transmission?
 

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Take the clutch side off first. You don’t need to drain the oil if it’s on the side stand.
See if you can move the clutch basket in neutral
 
Does the bike try to drive forward even though its in neutral?

You will need to split the case and examine everything. I cannot think of what that piece of metal would be off the top of my head.. Some kind of shim? Was it in the catch tray on the bottom of the engine?

Take the side cover off and examine the clutch pushrod area where the seal is. Is the seal intact or is it blown out?

That piece of metal could be from one of the seals maybe.
 
Doesn’t try to move forward nothing is moving at this point

Seals look intact to me, the pushrod is clear I even fished out the ball with a magnet.

My question is what is the best way to split the case without taking off more stuff than I need to. I am concerned that I won’t be able to take the cam off as the crank doesn’t rotate.
 

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Ok split the case tranny was perfect
Right cylinder would not move took their heads off then took the cylinders off turns out the connecting rod bearing was spun

What do you think should I machine or by rotating assembly?
 
If I was you, Id call that engine toast. Connecting rod bolts are one-time use and they are very hard to find. Bearings will be the same situation, all of it very expensive. Finding a machine guy can be difficult. The local guy 70 miles away from me specializes in Harley stuff, I waited for 3-4 months for a cylinder rebore.

What you could do is find a used complete bottom end and just put your top end assembly on it. This is probably the easiest and cheapest way to go.
 
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