APM Clutch (i.e. Pro Clutch)

[billbuilds]

    If you wind the shoulder bolts all the way in and the diaphragm spring is not compressed to within.010 -.020 of flat you need to add special shims to the shoulder bolts before you start them in so that you effectively move the spring retainer inward a bit.

[JW113]

It is true, I don't know if he tightened the nuts or not, but at time 7:08, it shows him doing it. It also seems strange that he's show how to measure the compressed height without the nuts tight.
 

I guess I could try to loosen the nuts and see what effect that has. I am currently measuring the compressed height at .014", and that is with the four smaller shims on the studs.

-JW

[kd]

It's possible the demonstration is just that.  It may be the only way to show enough of a gap in the video and it is just to give the point of measurement, not what a good measurement would look like.

[FSG]

        the old for demonstration purposes

[76shuvlinoff]

When trying to install the "Rivera" kit I got from APM I couldn't start the nuts without pushing hard enough to deflect the spring. Do you have that issue JW?

My old standard plates measure .046" to .047". Would using two of those instead of the .120" get you were you need to be for spring arc?

Seems in the end I was at better than .030" but I never write that stuff down. I haven't had it out on the road yet this year but it did get a few miles on it before I put her away and it seemed to be holding fine.

Mark

[Ohio HD]

JW, do you have another clutch cable? If so, worth a try before pulling yer hair out. It's possible that the cable was fine with the previous spring pressure. But with the heavier spring the inner cable is being pulled inside the jacket and dragging. 

Worth a 15 minute change if you have one on hand. 

[JW113]

I don't, unfortunately. However, the one on the bike is teflon lined, and maybe 5,000 miles on it?

Mark, I had no issue at all getting the spring plate nuts started. This is a brand new APM unit, 1056-0002, installed in my '77 clutch shell. It all went together exactly as described in the instructions, and also as shown in that video. It really truly feels like pulling against a very heavy spring. One thing that has my interest, this kit came with the silver "competition" spring, instead of the black "street" spring, which says "for stock applications and soft driving styles". Hey, that's me and my bike! I note that these diaphragm springs work in ALL APM and Rivera clutches, from Shovelhead to Twin Cam. I can easily see how a big inch Twin Cam drag bike would need a pretty heavy duty clutch, but my little Shovel? I am going to talk the APM guy today and get one of those black springs. So, stay tuned...

-JW

[david lee]

I don't, unfortunately. However, the one on the bike is teflon lined, and maybe 5,000 miles on it?

Mark, I had no issue at all getting the spring plate nuts started. This is a brand new APM unit, 1056-0002, installed in my '77 clutch shell. It all went together exactly as described in the instructions, and also as shown in that video. It really truly feels like pulling against a very heavy spring. One thing that has my interest, this kit came with the silver "competition" spring, instead of the black "street" spring, which says "for stock applications and soft driving styles". Hey, that's me and my bike! I note that these diaphragm springs work in ALL APM and Rivera clutches, from Shovelhead to Twin Cam. I can easily see how a big inch Twin Cam drag bike would need a pretty heavy duty clutch, but my little Shovel? I am going to talk the APM guy today and get one of those black springs. So, stay tuned...

-JW

im interested in the solution.i thought these clutches were bolt on and go

[JSD]

JW is the inner hub that fits on tapered mainshaft made from Aluminium? if so be carefull when torquing nut as they spit the hub at the Keyway.

[ghostrider]

Theres a reinforcement ring that's available to press onto the area near the keyway to keep them from splitting,  worthwhile part to install.

[JW113]

I don't recall if it's aluminum or steel, but appeared beefier than the stock hub. Stock hub is 75 ft/lbs, the APM instructions say 80-90 ft/lbs.

Got my "stock" black spring today, will install this morning and see what shakes.

-JW

[JW113]

OK, some progress to report.

I pulled out the "silver" spring and installed the "black" spring, and measured the diaphragm dome and confirmed .015" of arc.

Using my linear pull force gauge, I now measure:

Black Spring = 22 lbs pull force.

For reference:

Silver Spring = 32 lbs pull force

2004 RK with SE Heavy Duty spring = 22 lbs pull force

1992 Softail, with 2002 stock clutch = 16 lbs pull force

1978 Ironhead with stock clutch = 17 lbs pull force

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The pull force on this APM is now at a place that I can live with, but damn. It is not the "two finger clutch" that is advertised, unless those two fingers belong to Popeye the Sailor or Arnold Schwarzenegger. I'm just a sickly old geezer, so I guess the two finger pull thing is all about context.

I sent an email to Ben at API, along with a Power Point with lots of pics and descriptions. Waiting to see what he has to say.

-JW

[JSD]

Theres a reinforcement ring that's available to press onto the area near the keyway to keep them from splitting,  worthwhile part to install.

Who makes the ring?

[FSG]

Zippers had one, V-Twin 18-8240 , Custom Chrome 15-060 , quite a few around

[JW113]

Weeeellll.... Alrighty then!

After I put the spring in, was going to go out for a test run but decided to toss some oil down the clutch cable, just for grins. My bottle of Tri-Flow was empty, so instead used some Bike Aid liquid moly-graphite dry film lube for bicycle cables. The APM dude had told me that the majority of the time, the problem with heavy clutch lever feel is due to the cable, but I couldn't see how that could be in my case. New-ish cable, oiled not that long ago. Or was it...? I keep forgetting about the whole 2 years worth of Covid lock down, and the fact I have hardly ridden anywhere, which means not very many oil changes/chassis lubes in the past 3 years. Zero of them, to be exact.

So... after oiling the cable, the clutch pull force went from 22 lbs to 16 lbs, and nice 5 lb reduction. It now feels exactly like the clutch lever on my Evo softail. I took it for a spin, and boy oh boy do I love this clutch now. As everybody that has installed a Pro clutch in their Shovelhead has reported, it is freakin' AMAZING how the transmission shifts now. Instead of that attention getting KLANK when going from neutral to 1st at a stop, the lever just drops down with no feel and no noise what-so-ever, leaving you wondering if even went into gear. And shifting up/down between gears has like a 90% reduction in the KLANG factor as well. Now that I've put some around town miles on it, it feathers like a dream, especially with this new black diaphragm spring, which also appears to be hold back that monstrous 75 ft/lbs (LOL!) of torque. Just my opinion, but I think the "competition" silver spring that came with it is way overkill for a stock bike like mine.

Am a very happy camper now. Think I'll go out for a little joy ride just for the hell of it.
 

-JW

[Ohio HD]

Cable....   who'd a thought....           

[Hossamania]

The battery can't be bad either.................

[FSG]

[JW113]

Cable....  who'd a thought....           

OK, OK, I deserve that! But still, that silver spring was really over the top, and if the cable was adding 5 lbs of drag, that still means 28 lbs of lever pull for the silver spring. No thanks!

Hoss... hun?


All of the ponies are on a Pulse Tech Xtreme battery charger. Have not replaced a battery since... hmm, can't even really remember.

-JW

[Ohio HD]

OK, OK, I deserve that! But still, that silver spring was really over the top, and if the cable was adding 5 lbs of drag, that still means 28 lbs of lever pull for the silver spring. No thanks!

You know I have to give a small dig.   

I still don't know why someone hasn't designed a small servo driven clutch actuation. Fast, all the travel you want, and adjust it any way you would like.   
 

[david lee]

Cable....  who'd a thought....           

OK, OK, I deserve that! But still, that silver spring was really over the top, and if the cable was adding 5 lbs of drag, that still means 28 lbs of lever pull for the silver spring. No thanks!

Hoss... hun?


All of the ponies are on a Pulse Tech Xtreme battery charger. Have not replaced a battery since... hmm, can't even really remember.

-JW

so changing to the black springs was the fix ?apart from the cable

[JW113]

Yes. All the difference in the world. Can't say enough now about the way the clutch works.

-JW

[JW113]

OK, OK, I deserve that! But still, that silver spring was really over the top, and if the cable was adding 5 lbs of drag, that still means 28 lbs of lever pull for the silver spring. No thanks!

You know I have to give a small dig.   
 

But of course you do! It's what keeps us all honest.
 

I'm all for admitting for screwing up. Catch me when I don't, call me out. Please!
 

-JW

[76shuvlinoff]

After the first time I lubed the cable on my stock shovel I sat down and did this. 

Glad the clutch upgrade is panning out for you!

[Hossamania]

"Hoss... huh?
"

Just being a wise ass! Glad you got it working.
I'm sure you figured out what I meant, so many times people have running or starting issues and state it is not the battery, it tests good, it's brand new (or only two years old), etc., and it turns out to be a bad battery. Your cable fix reminded me of it, can't be the cable, it's new, just lubed, etc.!!
Had to give a little grief.