C: Clutch Increasing clutch lift for multiplate clutches

[Oldhaven]

Well off topic, but my brother and I bought our first "real" motorcycle, a 1948 61ci Harley, at the Lansing Michigan Shop of the "Old Jack Piner" Oscar Lenz when we were in high school. The event was a big deal in the area, and my uncle was an avid spectator. I am sitting on one of his bikes in my avatar.

 

[BigEd]

Might be a good idea to start a new thread if you want to talk Harley rather than use this thread.

 

[Nigel Spaxman]

I have run a V2 clutch for about 12,000 miles now. I use some plates from Barnett that are Kevlar, they are meant to run wet. I run mine in oil the inside is removed from my primary cover so the oil in the chain case is all over the clutch. This clutch doesn't drag or slip. When the engagement gets a bit grabby it is a sign that the oil level in the chain case is getting low. I run the oil level so the chain is just covered when I look in the filler hole. I use oil suitable for wet clutches, usually just motorcycle 10w 40 oil that is for modern bikes. Sometimes I have used ATF. Sometimes I have bought special oil for motorcycle primarys. To stop the clutch from dragging I did need a bit more lift than the original mechanism provided. I use a lever with 1 1/8" between the pivot center and the cable hole. I also installed a different clutch adjuster bolt in the gearbox outer cover. This bolt instead of a ball on the end is flat. It had to be installed from inside the cover. That moves the pivot point out a little bit. With these two changes I have just enough lift so the box goes into neutral easily and shifts really well. I run four clutch springs. The clutch has 6 springs but I found that with the 6 original springs the action was heavy and with three springs the clutch slipped. I did all these mods during the first few weeks of riding the bike and have left it alone since. The clutch can be lifted easily with two fingers and even with one if you try hard.

 

[hadronuk]

When I bought my Rapide, it was fitted with a V2 clutch with the bronze coloured sintered metal friction plates, running dry.
These offer the big advantage of a appreciably higher coefficient of friction than fibre plates running wet.
So only light springs are needed.
In turn, the lower lift force causes less deflection in the lift mechanism, so more lift.
The plates also don't appear to wear out, in spite of doing some drag racing at Shakespeare County Raceway.
The big downside is grab, which all-metal clutches are notorious for.
Ducati MHR owners whose bikes are fitted with apparently identical plates cure grab with an extremely small amount of grease. Tried it, it works, but stronger springs needed and after about 600 miles the plates get sticky.

My grab cure is to dip the friction plates in a 5% solution of dry lubricant and allow to dry, then refit.
Minimal reduction in coefficient of friction, grab cured, minimal clutch drag. Clutch action is light and very similar to the standard clutch.
Not quite sure how long this grab cure this is good for, as I foolishly removed my housing breather and a trace of oil vapour eventually made the plates slightly sticky after 2000+ miles.
I expect to do better with the breather now reinstated.
I should add that on my bike the housing cannot breathe via the dynamo mounting as that area was bodged and my repair is oil tight, so I bought a VOCSP reject ET63 and fitted a banjo for a breather pipe.
Ducati sintered plates are still available so could be retro fitted to V2 clutches instead of the fibre faced plates.

 

[passenger0_0]

My V2 clutch also tended to grab for a few years and I just accepted this as normal until I gave it some brutal slipping when negotiating a 30 mile traffic jam. That fixed the grabbing and it's been perfect since then. Mt thoughts are that I had burnt any trace of oil or grease from the sintered plates.

 

[bmetcalf]

Clutch lube! For us with standard clutches, that is quite a concept.

 

[hadronuk]

My V2 clutch also tended to grab for a few years and I just accepted this as normal until I gave it some brutal slipping when negotiating a 30 mile traffic jam. That fixed the grabbing and it's been perfect since then. Mt thoughts are that I had burnt any trace of oil or grease from the sintered plates.

When it first started grabbing, I thought all it needed was cleaning. Frequent strip downs to remove the gumified oil mist off was an improvement but not a cure. So next I overhauled the primary drive, new oil seals, great attention to sealing off the clutch, new primary drive breather so no pressure to push oil mist past seal. Result: totally oil free clutch, but grabbing still a problem. So I tried super de-greasing with Methyl Ethyl Ketone. The grabbing got much worse, really violent. I guess if everything is super clean, the clutch plates behave like slip gauges wringing together. So then I did the research, found that grabbing is an inherent problem with all metal clutches, and found the Ducati owners "fix". It appears its all about the exact surface condition of the friction plates, a trace of a friction modifier makes all the difference. Sounds like your "brutal slipping" removed enough of, or changed the character of the gummified oil film to something more optimum! But can you repeat the exact process when required?!

 

[John Appleton]

When it first started grabbing, I thought all it needed was cleaning. Frequent strip downs to remove the gumified oil mist off was an improvement but not a cure. So next I overhauled the primary drive, new oil seals, great attention to sealing off the clutch, new primary drive breather so no pressure to push oil mist past seal. Result: totally oil free clutch, but grabbing still a problem. So I tried super de-greasing with Methyl Ethyl Ketone. The grabbing got much worse, really violent. I guess if everything is super clean, the clutch plates behave like slip gauges wringing together. So then I did the research, found that grabbing is an inherent problem with all metal clutches, and found the Ducati owners "fix". It appears its all about the exact surface condition of the friction plates, a trace of a friction modifier makes all the difference. Sounds like your "brutal slipping" removed enough of, or changed the character of the gummified oil film to something more optimum! But can you repeat the exact process when required?!

I fitted a multiplate clutch about ten years ago. I believe it was made in Coventry, but I do not know for certain. I experienced all of the short comings listed in this thread, and tried all of the listed cures, non of which worked for any length of time. I could get it to operate initially,but by the time I rode out of the continental ferry ports it had reverted to a shrieking, grabbing monstrosity that spoiled several holidays. Then I discovered how to solve the problem! I removed it and fitted it to a shelf in the workshop (where it still resides) . I then took my original clutch and removed the "bodge thy beast" washers etc, and ensured all settings and clearances were as per the designers specifications. The result has been a clutch that is light in operation, does not slip or grab, and causes me no stress whatsoever. It has covered many miles, and it's original test run took me to Turkey and all points east, and this was in 2010. John.

 

[hadronuk]

I fitted a multiplate clutch about ten years ago. I believe it was made in Coventry, but I do not know for certain. I experienced all of the short comings listed in this thread, and tried all of the listed cures, non of which worked for any length of time. I could get it to operate initially,but by the time I rode out of the continental ferry ports it had reverted to a shrieking, grabbing monstrosity that spoiled several holidays. Then I discovered how to solve the problem! I removed it and fitted it to a shelf in the workshop (where it still resides) . I then took my original clutch and removed the "bodge thy beast" washers etc, and ensured all settings and clearances were as per the designers specifications. The result has been a clutch that is light in operation, does not slip or grab, and causes me no stress whatsoever. It has covered many miles, and it's original test run took me to Turkey and all points east, and this was in 2010. John.

Congratulations to the few who have mastered the arcane rituals needed to make the original twin clutch work as it should.
One day I aspire to join you, and I have collected together the necessary parts to do so.
But I lack much incentive to do it soon, because as Big Ed can verify, my V2 clutch is pretty much is as good as the original.
And if the V2 gradually gets a bit grabby, I can restore it to perfection it less than an hour without jigs and measurements.
If the original was easily put to rights and stayed that way, I am left wondering why so many alternatives to the original clutch were engineered and marketed?

 

[Peter Holmes]

The installing of a multiple clutch is a retrograde step, it should be understood that the the first 998cc HRD motorcycles, the Series A Twins, had multiplate clutches that were found to be inadequate, so a brilliant Australian engineer, Phil Irving designed a revolutionary alternative to that archaic and troublesome device, the single plate assisted servo clutch, as John Appleton states, it is the only clutch that you will ever need.