Clutch Slippage

[rayray22]

With the continued talk of moly affecting the clutch, I wondered if habits might have anything to do with it.
It seems to me the only time lube gets into the clutch friction side of things would be when the motor is stationary and the clutch disengaged. I would think that when the clutch is spinning, centrifugal force would not allow oil to enter.
Is this correct?
If it is and you're worried about moly (which I'm not), then don't pull the clutch in to start the bike.

 

[JonS]

Good question. So if your idle in neutral, you get oil between the plates?

 

[Warlord]

From what I understand heavy duty clutch springs will almost always cure this problem. IMO clutches that are already worn out are the usually the only ones that are likely to slip using car oil.

 

[swjohnsey]

Moly in the amounts found in car oils does not cause motorcycle clutches to slip. If you have any doubts check out the UOA for the ZX-10R runnin' Redline.

 

[Titan]

Quote:

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With the continued talk of moly affecting the clutch, I wondered if habits might have anything to do with it.
It seems to me the only time lube gets into the clutch friction side of things would be when the motor is stationary and the clutch disengaged. I would think that when the clutch is spinning, centrifugal force would not allow oil to enter.
Is this correct?

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Not quite. They don't call them "wet" for nothing!

 

[PT1]

#@$%! is this? Tell you what to do to really understand clutch lubrication. Take the derby cover off a Harley and go riding on the interstate.....

 

[mechtech2]

Wet clutches are bathed in oil. They have sipes in their faces so the oil will squeeze out faster. This also lets oil in. Consider them a soaked part - you'll never see a wet clutch that isn't sopping wet.
Most can handle a little moly, but you don't want to intentionally add a lot of slick stuff.

 

[kliff]

The "friction discs" of an M/C clutch are porous, they hold oil. In fact they are soaked in oil before intial installation. If you are not worried about Moly, and think you can "trick" your clutch into not slipping, then go for it....

The frictions are still going to be porous, they are still going to absorb whatever you have in your primary whenever it is shut down, and the moly, IF in high enough content, will eventually effect clutch action.

I have personally used oils (M1 auto 15w50) with a moly content of 90ppm with no problems. I have also worked on bikes using oils with a moly content of 200ppm that required a thorough cleaning of the entire inner primary, clutch basket, and a friction disc set replacement to restore proper clutch action.

But, hey, you gotta do, what you gotta do....

 

[wileyE]

Not all wet clutches are the same when talking about slipping and moly etc. Some may be bigger or smaller in diameter, some may have more or less friction plates ( total friction area), the primary gear ratios may have one with more torque load on it than another driven at a different speed, vehicle weight, overall gearing, engagement spring tension, friction plate material, engine torque. In other words all are not created equal and may respond different to the oil used. Some bikes slip the clutch even with the "proper" MA cycle oil. Some never do with whatever you throw at it. Think the only rule of thumb is to err on the safe side, or get familiar enough with the bikes history and experiences of others with the SAME bike. Otherwise it's just apples to oranges when comparing oil results.

 

[PT1]

Quote:

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Not all wet clutches are the same when talking about slipping and moly etc. Some may be bigger or smaller in diameter, some may have more or less friction plates ( total friction area), the primary gear ratios may have one with more torque load on it than another driven at a different speed, vehicle weight, overall gearing, engagement spring tension, friction plate material, engine torque. In other words all are not created equal and may respond different to the oil used. Some bikes slip the clutch even with the "proper" MA cycle oil. Some never do with whatever you throw at it. Think the only rule of thumb is to err on the safe side, or get familiar enough with the bikes history and experiences of others with the SAME bike. Otherwise it's just apples to oranges when comparing oil results.

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Very true.....but I use Redline MTL in wet clutches because it's GL4 and no moly. Harley syn3 20w50 has no moly as well. So why use anything else?

 

[arkie6]

The clutch on my Yamaha FZ1 (similar to an R1 engine) has oil pumped into the center part of it from the transmission input shaft.

I've been running Chevron Delo 400 15w40, which contains ~200 ppm moly, for many thousands of miles now. The bike has 32,000+ miles on it with original clutch. I've never had any clutch slippage issues. The bike will easily power the front wheel off the ground in 1st or 2nd gear.