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bike locked up...where to start?

2372 Views 18 Replies 8 Participants Last post by  admiral
"Broke" the bike tonight... will start tearing it down tomorrow but wanted to see if anyone has any pointers on where to start, and/or tips and tricks to make the next few days of my life a little easier.

I am not sure if the transmission is locked up or the engine, but no need to get ahead of myself.

Was going downhill about 20-25mph, bike quit and rear tire locked up. All very sudden, no warning. Kickstarter moves a little, but not sure if this is just "taking up play" in the mechanism, or how it even works really. Seems locked up pretty solid so could not start bike.

Had the flywheel off on Sunday night, so I started by laying the bike over on its side and removing left side case. Nothing visibly amiss. Starter gears all turn, but crank will only turn approx. 15degrees. Removed cam cover, nothing visibly amiss. Same 15degrees of rotation as the crank. Removed cam chain tensioner, managed to jump teeth on chain by turning crank. This leads me to believe that piston/crank are moving freely.

Managed to get the bike shifted into neutral at some point, but after that it would no longer shift at all. This makes me think transmission is culprit. Bike rolls around fine in neutral.

Any thoughts? Where would you start if you found yourself in the same position? (Aside from trucking the bike home for the second time in a week)

Let me know if you have questions for clarification, these might not be all the details just throwing the info out to get some expertise
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That is the kinda stuff I was looking for. Had no idea the trans was reached through the top end. Service manual is hard to read on a cell phone....
How difficult is it to pull the motor, I wonder? This job sounds like it would be a lot nicer in my dining room, rather than the old horse stall the bike is kept in
10-4 on the usefulness of shop manuals, have a shelf with about $1500 worth. Still need to print out the TW manual though you are right.

Have not checked under clutch cover yet for messed up stuff, that is the next step but have to drill out a JIS machine screw that the dumb previous owner stripped out, and the dumb current owner stripped further.

I take it you do not advocate removing the engine without first determining the issue? Makes sense.

Thanks for the tips, I will dive into it tonight after work to find the problem. Does it make sense that the cam and crank are not siezed if I can rotate them approx. 15 degrees each?
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There is a metal retaining plate under the cam sprocket that has an "ear" that fits into a recess on the end of the cam. I have never touched this part before, but somehow the "ear" tore/bent, allowing the end of the cam (bearing? Still can't get manual to work on my phone) to turn in a manner that I can only imagine it shouldn't, or else the retainer would not exist. It continued to rotate until the "ear" was binding everything up. I noticed this when loosening the cam sprocket bolt, because everything rotated all of the sudden, letting me see what was going on.

With the cam chain unhooked, the crank spins as it should. Was able to get it into gear (not sure what was up with that?) And turning the crank turned the chain as well.

Since I have the head off now, the whole thing will probably be gone through. It would sure be nice to ride for a whole season without catastrophic failure of some sort.
Can't post pics directly from phone. Will put some up later. Need to look at service manual...

Today is "run new brake lines on the car" day, and will be at an auction tomorrow morning buut it would be good to talk to you about it all, given your recent experience
Still no pics to post, but just wanted to let everyone know that it was the same failure as when you put in the wrong oil filter. Top end starved for oil and the cam "collar" in the head spun.

This is likely due to my stator explosion two days before hand. I changed the oil but something must have gotten plugged up, causing the oil starvation.

Looks like another member has a head I can buy, so should be back in the saddle in short order.
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