HarleyTechTalk

Technical Forums => Shovel Head => Topic started by: Dave_R on May 29, 2020, 10:03:16 AM

Title: clutch spring difference
Post by: Dave_R on May 29, 2020, 10:03:16 AM
Greetings,  Sorry if this has been asked before, but I could not find a good answer.

I came in possession of a 79 FXE recently with an S&S evo style engine (the original one blew quite a few years ago and the owner traded it for the S&S).
With this engine, it has a bit more power than the original.  This causes my clutch to slip when i'm in fourth gear and "get on it".  I've pretty much bottomed out the clutch springs trying to keep it from slipping, and came to the conclusion that I would need heavier springs.  My question is (I'm a Panhead guy and this is my first Shovel) what is the difference between clutch springs?  I see springs that are for 1968-E84, and others for earlier models.
Reason I ask is that i have several clutch spring sets for Pans, and I don't see the difference other than the older ones seem a lot stiffer, and the coils look like they are made from heavier wire.  I would like to put a set in the FXE and try it out, but thought I would ask out of curiosity before I do.

Will it harm anything?

Also, I am assuming this is a dry clutch, as there is no oil in the primary, and the primary inner cover does not seal around the engine.  However, when I got the bike, the owner handed me a handful of nylon adjuster shoes, says " I will need them as these will be replaced quite often".  Almost looks like is should be a wet system, as no oil is directed onto the chain anywhere.  i think the oil lines were re-routed during the S&S engine install.

Thanks in advance!
- Dave
Title: Re: clutch spring difference
Post by: JW113 on May 29, 2020, 10:57:17 AM
You are going to have some fun here.

The stock Shovelhead clutch is fine for most stock-ish Shovelhead motors. Guys that hot rod the stock motor tend to find the clutch is then not up to snuff. I'm pretty sure that S&S motor is going to have a fair amount more torque than a stock Shovelhead motor. Your problem is not like a simple replacement of springs.

I think there is a set of heavy duty "red" springs that you can try. From what I know of them, the clutch lever gets to be a real bear to pull, and the clutch action gets funky since the flippy-floppy stock clutch basket & bearings were not really designed for heavy springs.

"Dry" clutch? That is somewhat a misnomer. Kind of like a "dry sump" for the motor vs. "wet sump". The stock clutch set up is indeed 'dry', but the primary is not designed to run dry. Stock has the engine oil circulating through the primary to keep the chain wet. With no oil, yes the adjuster shoe is going to get worn out in no time. That is probably find for a bike that gets ridden 20 miles a year. The only true "dry" primary is belt, with no adjuster shoe.

I think the best solution for your situation is to buy a Rivera Pro Clutch, which uses a diaphragm spring like the Evo and later clutches do. Most of the guys on this forum that have them swear by them. You also need to get oil into the primary. Most guys seal all the oil supply/return holes, and run about 8oz of ATF in the primary, making it a sealed wet sump but with just enough oil to keep the chain wet and not soak the clutch plates.

I'm sure more dudes will chime in this. My opinion, you have some work to do and decisions to make.

-JW
Title: Re: clutch spring difference
Post by: Ohio HD on May 29, 2020, 11:30:35 AM
New steel plates, new Barnett fiber discs, new Barnett clutch springs, aluminum pressure plate, clutch tamer, it'll hold a stockish Evo fine. This same recipe will hold a street ridden 98" Shovel.


http://www.barnettclutches.com/1372/harley-davidson/0/0/0-harley-davidson-1941-early-84.html
Title: Re: clutch spring difference
Post by: JW113 on May 29, 2020, 12:31:13 PM
How is the clutch lever action on a clutch like that?

-JW
Title: Re: clutch spring difference
Post by: Ohio HD on May 29, 2020, 12:40:18 PM
Not terrible. Shovels had pretty easy clutches when the Teflon lined cables came out.
Title: Re: clutch spring difference
Post by: Ohio HD on May 29, 2020, 01:50:37 PM
You can also add a few peso's to the project and make a one time purchase. Won't ever slip, easy clutch pull.


(http://www.barnettclutches.com/prod_images/large/608-30-10036.jpg)
Title: Re: clutch spring difference
Post by: JW113 on May 29, 2020, 01:51:45 PM
Yeah, my stock clutch with Barnett lined cable is a one finger pull. I've only heard the grumbling of the coil spring type clutch with heavy springs. Never tried the Barnett clutch myself, so can't compare. Good to know it's reasonable pull on the lever.

-JW
Title: Re: clutch spring difference
Post by: david lee on May 29, 2020, 02:48:07 PM
whats your guys thoughts on a 3 finger hub to a 5 and the stock caged bearings to the 52 rollers. some say the stock is better. why ? thanks
Title: Re: clutch spring difference
Post by: JW113 on May 29, 2020, 03:43:37 PM
As far as I can tell, the whole 5 finger thing is marketing hype. Both have 10 studs taking the torque load. 3 finger has 3 adjustment nuts, the 5 finger has 5. The adjust nuts have a 1/2 turn lock dent, so your adjust resolution on each finger is 1/2 turn. With 3 fingers, you will have the spring plate fully seated on all three studs. With the 5 finger, you're highly likely to have the spring plate seated on three studs also, with the other two not fully seated as the chance all five fingers have the threads all lined up exactly the same is highly unlikely.

The bigger question is, what does two more adjustment nuts get you, anyway? Don't make a whole lot of sense to me.

-JW
Title: Re: clutch spring difference
Post by: Ohio HD on May 29, 2020, 03:47:02 PM
Five stud hubs empties your wallet is about it.
Title: Re: clutch spring difference
Post by: guppymech on May 29, 2020, 06:13:07 PM
My clutch basket had a worn area in the bearing track for the stock rollers.  I switched to the 52 long rollers, they roll right over the worn part without hitting it.  I think the long rollers came about because the earlier clutch basket bearings were balls instead of the staggered small rollers and they wore tracks into the bearing surface.   The 52 rollers tighten up the clutch which may or may not be a improvement as the wobbly nature of the stock bearings help the clutch plates separate on disengagement.  Also to use the long bearings you turn the bearing retainer plate around and when you do that it lets the bearing grease out into the clutch plates so I use very little lube which hasn't been a problem in 8k miles so far.
Title: Re: clutch spring difference
Post by: RTMike on May 30, 2020, 07:17:13 AM
Primo Pro Clutch and 8-10 oz of oil ,problem solved and no more dicken around.
Title: Re: clutch spring difference
Post by: Dave_R on May 30, 2020, 10:03:23 AM
These suggestions are all great!  Many thanks.

Just curious for my future knowledge...  does anyone know what the difference is between early (pans and back) versus 68 and up clutch springs?  Some replacement springs say 41. And up, some say 41-67, and others say 68-84.

Seems to me that these should all be the same.

Many thanks for the suggestions.

-Dave
Title: Re: clutch spring difference
Post by: Ohio HD on May 30, 2020, 10:13:34 AM
Real early years had a mousetrap, and used heavier springs. Also somewhere in the years there were less plates, so heavier springs, '68 up is the modern Shovel clutch mechanisms.

I could look them all up, but I'm not.   :SM:
Title: Re: clutch spring difference
Post by: crock on May 31, 2020, 03:43:01 AM
http://www.barnettclutches.com/1372/harley-davidson/0/0/0-harley-davidson-1941-early-84.html

41 to 67 uses a 50 lbs spring. 68 to 84 uses a 40 lbs spring. I run the early springs (50lbs) with an aluminum pressure plate and Barnett Kevlar plates with 4 to 6 oz atf in my 98" shovel riding 2 up all day with decent lever pull and no slip
If you want to build your forearm Barnett also has their 68lbs srings
Title: Re: clutch spring difference
Post by: 76shuvlinoff on May 31, 2020, 06:06:48 AM
Quote from: RTMike on May 30, 2020, 07:17:13 AM
Primo Pro Clutch and 8-10 oz of oil ,problem solved and no more dicken around.

Same here. 93" S&S in front for over 30K miles, zero dicken. Not knockin other clutches I just haven't tried them. I did try most all of the magic fixes with no success.