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mcgee3512
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VBMWMO #3512
Creola, AL
Joined: 10/27/2006
Posts: 27

The clutch on my R90/6 1975 slips under power. The adjustment appears to be OK. I just did the crankcase reed valve update because I was experiencing a little blow by when riden agressively. My concern was the blow by was getting on the flywheel/clutch disc/pressure plate. After the upgrade it appears worse. RPM's over 4-4,500 will cause the clutch to slip badly. Looks like a new clutch pressure plate and throw out bearing is in my future unless anyone on this forum can come up with another reason as to why this is happening. :cry:

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Tim McGee

1973 R75/5 LWB
1975 R90/6
1982 R65
2009 FLHR Harley (Road King)

schrader7032
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VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6671
R90/6 Clutch Slippage

How many miles on the clutch? What kind of miles...all highway, mostly city, mix? I've got +80K on my /7 clutch and that's mostly highway miles, and all seems fine so far.

I think it's virtually impossible to get engine oil on the clutch, especially from blow-by. The only way I believe for oil to get into the bell housing is for it to come out the rear main seal, but then the oil would be on the opposite side of the flywheel. It could drain down the front side of the flywheel but would have to "run uphill" to get anything significant on the clutch. Not the absolutely correct picture, but the point is the flywheel separates the clutch from the rear main seal.

Sounds like the clutch is just worn out. Or you could have transmission oil migrating out the the front seal or down the clutch rod and getting on the clutch.

Probably time to pull the transmission and take a look. Lubricate the splines at the same time. If there's that many miles, maybe look into changing the rear main seal and oil pump o-ring. Be warned, if you do this yourself, especially removing the flywheel, be sure and block the crankshaft from moving foward. If it does move, some shims will fall off their locating pins and you're day will be ruined...a full engine teardown would be in order. Be careful out there!!

Kurt in S.A.

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

mcgee3512
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VBMWMO #3512
Creola, AL
Joined: 10/27/2006
Posts: 27
R90/6 Clutch Slippage

Not sure on the miles. I'm not the orginal owner but have owned it for 10 years. Odometer shoes 37,000. I have it set up like a cafe racer and ride it in the mountains mainly.

My thinking about the blow by. The crankcase ventilation valve is right at the end of the starter bendix. You can see the flywheel. I have had trouble with a oil mist showing up at the seams of the air cleaner after a hard days ride. I wondered if some of that mist had gotten on the flywheel.

I think you may be right. It clutch time. I only notice when I ride aggressively. I will take it easy and start to assemble some parts.

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Tim McGee

1973 R75/5 LWB
1975 R90/6
1982 R65
2009 FLHR Harley (Road King)

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