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ThompsonJP
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Vancouver, Wash.
Joined: 05/22/2014
Posts: 17

I'm in the process of changing the rear main seal on my 1974 R90/6 (late '75 engine) and I took everyone's advice and blocked the crankshaft with a small socket and a tiedown strap. I snugged it as hard as a I could to keep the dreaded shim from falling into my engine.
When reinstalling the flywheel I had to secure it with a homemade tool to stop the flywheel from turning. I torqued the bolts, put the clutch back on and adjustednit. Now I can't get the flywheel to turn when I put the bike in gear. I have it on the ground and when I put it in gear and push, the back wheel just skids.
Am I sunk and need to get the engine taken apart to reset the stupid shim or is there any other explanation I could look for?
Thanks

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6540
Hmmm….bike's in gear and

Hmmm….bike's in gear and you're trying to push the bike but the rear wheel skids. Seems to me that's normal??? It's a bit hard for the small contact patch of the rear wheel to overcome the engine compression. It would have been obvious if there was a binding problem when the flywheel went on and once torqued or as you were torqueing it, you couldn't rotate the engine with the spark plugs out.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

ThompsonJP
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Vancouver, Wash.
Joined: 05/22/2014
Posts: 17
With rear wheel up

So I got the rear wheel up off the floor. In neutral, I can spin the rear wheel. When I put it in gear, the wheel won't rotate, but has a bit of play. When I pull in the clutch, the wheel moves fine. The spark plugs and carbs are out. I don't know if this matters, but the clutch is new (reconditioned by Southland in National City, Ca.)
Any ideas, I'm still hoping it's not the crankshaft shim.

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6540
Well, something does seem

Well, something does seem locked up. If plugs are out, you should be able to turn the rear wheel in gear. You get more mechanical advantage if the transmission is in 5th gear.

Haven't heard much bad about the Southland clutch and don't know how something in the clutch could lock the engine. It's possible to put in the clutch plate backwards. I'm wondering if maybe something is protruding from the clutch plate which is hitting the ribs on the front side of the transmission housing.

Sounds like you're going to have to begin removing things until the engine frees up. Not too "horrible" to pull the transmission and inspect things. If at that point, you can't turn the engine by hand with plugs out, sure seems like the crank has shifted off the pins. Snowbum mentions possible damage to the case, so hope that's not the case.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

ThompsonJP
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Vancouver, Wash.
Joined: 05/22/2014
Posts: 17
figured out

Well, I got more practice taking out the transmission and clutch. Turns out the flywheel turns just fine. The resistance from the pistons was just too great for me to get the flywheel to turn with the back wheel. Guess I learned to trust my work.

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