Dry Clutch versus Wet Clutch

Production K Models

Dry Clutch versus Wet Clutch

Postby Mayday53 » Thu Jun 29, 2017 2:35 pm

TECHNICAL QUESTION for one of you K MODEL Gurus:

I was talking to an experienced bike builder today and he is rebuilding a 53 K model motor. He said they modified their 53K clutch assembly, using an aftermarket set up, to use a wet clutch system in lieu of the dry clutch. Apparently it is due to the dry clutch having so many issues with leaking fluid and then slipping clutches.

Discussion....begin please.... :?:
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Re: Dry Clutch versus Wet Clutch

Postby wz507 » Thu Jun 29, 2017 3:46 pm

If it was mine, and if you tend to operate the vehicle like a normal human being, I’d build the clutch with the parts I had on hand - either wet or dry, and either should outlast you. If you abuse the hell out of it, the dry clutch is definitely the more robust solution. The dry clutch version is basically what’s been used on XR flat track racers from the beginning of time, where nowadays the engines develop on the order of 100 HP, they do 2nd gear starts all season long and they slip the clutch the entire way out of the box until the 1st shift. With a wet clutch you can do this type of start exactly “1” time before the steel plates turn blue and become so distorted that the clutch will no longer disengage. And how, you might ask, do I know this ? ;)

Many modern bikes have full pressure oil purging through their wet clutch to cool it, which makes for a very robust clutch. Unfortunately our old steeds have no means of oil cooling the clutch hence the blue outcome under severe service. But under normal service the wet clutch is perfect as is.

If you do go the dry route, do a good job of sealing the clutch hub (seal all penetrations of the hub) and it should stay dry for many years. My $0.02
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Re: Dry Clutch versus Wet Clutch

Postby 55panman » Thu Jun 29, 2017 9:48 pm

Another thing about flat trackers is: the bike are always verticle on a center stand. And the rear wheel is always higher making the oil run to the front of the primary cover away from the clutch. They are not leaned over on a side stand that lets the oil in the primary rise to a higher level because of the angle of the bike. Especially if it's an old side bent stand with a bent frame lug. When you put away your K or Sporty in the garage at night put it on a center stand to keep it vertical and the oil level low.
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Re: Dry Clutch versus Wet Clutch

Postby chuckthebeatertruck » Fri Jun 30, 2017 10:23 am

This is a topic of great debate among early sporty riders as well . . . and given the overall clutch design didn't change dramatically from the K to the early sporsters, you may find this link helpful:

http://xlforum.net/vbportal/forums/show ... ?t=1690249

When I assembled my 59H, the good doctor helped me sort out how to keep the clutch dry. The previous owner had installed barnett wet/dry plates and did a horrible job sealing the clutch basket -- RTV and over torqued mess. It was a terrible clutch and I seriously debated getting an "upgrade."

I was then taught the first rule of owning one of these bikes is: "When in doubt, do it like the factory." So, I decided to listen to the ghosts of harley engineers past and get down to returning her to as built. After sorting the clutch, cleaning the fibers and buttoning it up -- it became a lovely piece of kit and I've had zero issues in thousands of miles of hard riding. I can find neutral at any speed, launches are easily controlled, and I can speed shift with ease up or down the range. All of these things are related to the interplay between the clutch, the hub, and the transmission.

It takes a certain amount of dedication to keep the clutch dry, but you can do it. There's no need to resort to modifying a great clutch pack for what amounts to a few simple fixes on a rainy afternoon.
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Re: Dry Clutch versus Wet Clutch

Postby 55panman » Fri Jun 30, 2017 1:21 pm

AS Dr. Dick says, use the stock parts and make sure they're assembled correctly. I ran my 1977 XR750 for 3+ years of Vintage racing. Full seasons + District 23 races. Probably 10 to 12 races a season plus full season winter indoor. That was a challenge herding a XR750 around and indoor short track. Finished class champion. Anyway, when I bought the bike only popped the primary, clutch looked good. Never changed the clutch plates or did anything to it always worked excellent. No slipping, no creep at the line, easy to find neutral. Again I think part of the reason was bike was always on race center stand through winter too, which because the rear wheel is up to facilitate easy removal for sprocket changes, kept the rear of the primary up and clutch out of the oil.
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Re: Dry Clutch versus Wet Clutch

Postby Mayday53 » Fri Jun 30, 2017 4:49 pm

THank you gentlemen...as always I am impressed. I will keep as the good 'ol HD engineers built it - dry for two reasons...first, I have the parts, second, you convinced me ti will be fine if I use a center stand.

Enjoy Independence day weekend!!!
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Re: Dry Clutch versus Wet Clutch

Postby Lisa » Fri Jun 30, 2017 6:20 pm

My 53 54 67 and 69 all have wet clutches with no covers and all have ben working fine for years with No issues at all, pull neutral at idle No problem No worries like dry clutches getting wet and screwing up - different strokes for different folks.
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Re: Dry Clutch versus Wet Clutch

Postby mikeslemmon » Sat Jul 01, 2017 11:55 am

Energy One wet or dry run wet has been working well for me for about 15 years
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Re: Dry Clutch versus Wet Clutch

Postby Mayday53 » Wed Dec 27, 2017 10:03 pm

Well, after much debate and dozens of conversations, I opted to put in wet clutch plates and leave cover off clutch basket. I WILL report back after this next summer, since I should FINALLY be finishing my KHK this spring!
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Re: Dry Clutch versus Wet Clutch

Postby Lisa » Wed Dec 27, 2017 10:22 pm

When final adjustment is done pull in clutch lever and wire it in so you can turn adjustment plate to see if it wobbles if it does turn in nuts to accomplish NO wobble ( true) then release clutch lever. perfect adjustment is done. Harley manual doesn't tell you that and it should.
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