APM Clutch (i.e. Pro Clutch)

[JW113]

I recently installed an APM Comp Master clutch in my '77. It is essentially identical to the Rivera Pro Clutch, and my understanding is that the two were designed by the same guy. While the clutch works, and solved my slipping problem, the force at the lever is off the chart. I called APM this morning, and got essentially zero help. He was convinced that I installed it wrong, or that the cable was binding. If you're at all familiar with this type of clutch, unless you get the disks/plates out of order, there is essentially no way to install it wrong that I can see. Before installing it, the lever force with the stock 10 spring clutch was hardly anything, and I didn't touch the cable when installing the APM. Just for grins, I removed the clutch adjust screw, and the clutch rod moves out with essentially zero effort. It ain't binding. And the cable is teflon lined with a touch of silicone oil. Friction is not the problem.

Also for grins, I used a linear force gauge and checked the clutch lever on my '92 Evo: 8 lbs pull force. Then checked my '04 Road King with SE heavy duty diaphragm: 13 lbs. And the Shovelhead with APM: 32 lbs pull force!

I'm at a loss. Everything that I have read, and what the APM dude told me today, the diaphragm clutch should have much less lever force than the stock 10 spring clutch. It ain't. Much, much more force than the stock clutch. I am at a loss what to do now. Any suggestions, other than pull the freakin' thing out.

-JW

[Ohio HD]

I've never installed one. But what comes to mind is making sure the spring is installed right side out to get the 0.010" to 0.020" bow they speak of. And in case they happen to sell a heavy duty spring, or could have received the wrong spring from their supplier, measure the thickness of the spring and ask them how thick it should be.

Added:
I see they list a spring part number 1-2059-0003 "medium"
That would imply they also have a "heavy" and maybe an "extra heavy"
I'd measure the thickness and call them.

I would think a stock bike, the clutch has 50% more friction surface, that you would only need a very light spring.

[Ohio HD]

I was right, they do have additional springs.


2059-0001 for stock applications color black


2059-0003 competition color silver


2059-0002 race applications color gold

[JW113]

I have the silver spring. Which is what comes with the kit and the dude said was suppose to have a light lever pull. I'm a-thinkin' I need to give the black spring a try. Thanks, round on the ends and high in the middle (O-hi-O). LOL!

cheers,
JW

[Ohio HD]

I have the silver spring. Which is what comes with the kit and the dude said was suppose to have a light lever pull. I'm a-thinkin' I need to give the black spring a try. Thanks, round on the ends and high in the middle (O-hi-O). LOL!

cheers,
JW

Wouldn't that be (o-HI-o)         

[kd]

   O hi O 
       /   
       U

[Ohio HD]

O hi O
    /   
    U

 

[JW113]

Oh you guys!

 

-JW

[72fl]

JW I have the Rivera and clutch pull is minor with no slippage (2 Finger) and does Mark on his 76. The only thing I can think of is the Clutch tightness needs to have a rewverse type Bow contour to the Spring when Installing. I attached Rivera's guide maybe they have something in there that isn't in your guide.

https://riveraprimo.us/pages/installation-guides?msclkid=64dd8918b7e911ecb545bc33d26b1c32

[76shuvlinoff]

When I finally replaced the discs and plates in my Rivera there was one thick plate I think was to go in last. Apparently the design is different now that it was in 2004.  The spring was practically flat and the lever would barely move.  I ended up taking that thick plate out and reusing an old thin one. Life is good.

JW, I have no idea why your's is so tight out of the box with all new parts.  If  you have a thick plate in the stack, and if the design is truly the same, I can send you one of the originals from my Rivera, free to a good home. . When I pulled them out they measured within .005" of the new ones they sent me.

The lever on mine doesn't pull harder than stock does with a well lubed cable.  It is stiffer than my 12 EG.

Here is my thread.
https://harleytechtalk.com/htt/index.php/topic,116382.msg1396314.html#msg1396314

[JW113]

JW I have the Rivera and clutch pull is minor with no slippage (2 Finger) and does Mark on his 76. The only thing I can think of is the Clutch tightness needs to have a rewverse type Bow contour to the Spring when Installing. I attached Rivera's guide maybe they have something in there that isn't in your guide.

Wow, that is trippy. Those Rivera instructions look like a carbon copy of the APM instructions, only with Rivera replaced by APM. It's even the same part number! Is the Rivera Pro Clutch a repackaged APM clutch?

Not sure what you mean exactly by "reverse bow contour" on the spring. The only way that I can see that it would work is to have the "dome" of the spring facing outward.

I got a response from Ben Kudon at APM. Not much help, just re-iterating that it is a two finger lever pull. I honestly don't see how one could install this clutch incorrectly, there is not really anything to it. And the parts are even marked which side faces out.
 

Mark, I might take you up on your offer. So you're saying ditch the .120" inner plate and use a standard plate? That kind of makes sense, as it feels like this thing is overly compressed. I'll ping you. Also, I think I will get one of those black diaphragm springs to give it a try.

Oh, and you were spot on. After a couple hundred miles, the thing is now a lot less grabby and easier to feather.
 

thanks,
JW

[Ohio HD]

JW, that's what I was asking about. That there is an 0.010" to 0.020" bow / curve in the spring. Center outward.

[JW113]

OK, full disclosure here. I did see that in the instructions, but indeed I did not measure it. Not because I'm lazy (don't ask my wife about that though), but because I could not figure out a way to measure it. Guess I need to put my thinking cap on. It looks easy in cross section view drawing, but in reality, not so easy. As in, how to get something in there to touch the top of the diaphragm and keep it perfectly perpendicular? Or maybe I'm missing something obvious?

You cannot view this attachment.

-JW

[JW113]

OK, here's a big DOHHH!!! I no sooner hit send above, and a light went off above my head: measure it as you would a primary chain, i.e. the depth from the hole in the outer primary. DOHHH! Running out the garage right now...

-JW

[JW113]

Hmmm. So that black spring retainer overhangs the inner end of the diaphragm, so you can't really get right up to the inner edge to measure the exact compressed thickness, but measuring from the outer edge to the surface nearest the spring retainer, I am getting .026". So it's a little more than that, maybe .030"? Which is .010" less compressed than they spec, with a monster for clutch lever force. WTF? I can only imagine what my poor throw out bearing is going through, guess it won't be long for this world.

-JW

[david lee]

im interested in the fix jw

[76shuvlinoff]

So you're saying ditch the .120" inner plate and use a standard plate?

I know it worked for me but I have an older Rivera hub. As I understand it the new ones are deeper and should accommodate that thick plate. As mentioned previously, with all the surface area in these clutches you do not need a performance spring in a stock bike.  I think I'd be looking at that but the offer of a used thin plate stands.

 If you read back through my thread on this topic billbuilds  dug into this issue, even contacted the manufacturer.  It reads to me like the new hubs will take  the thicker stack up of 1.7".

[ghostrider]

Did the kit come with any of the adjustment shims?  If it did you could always try using them and see if it helps.
To measure the arch you could try a short straight edge, like a full blade from an Olfa knife, and lay it accross the spring just south of the retainer, if you know what I mean. It won't be real wasy to see or measure the arch, but if its way off it should be obvious.  I've got my sitting here in front of me and I think that would work ok?   

[turboprop]

Rivera

JW I have the Rivera and clutch pull is minor with no slippage (2 Finger) and does Mark on his 76. The only thing I can think of is the Clutch tightness needs to have a rewverse type Bow contour to the Spring when Installing. I attached Rivera's guide maybe they have something in there that isn't in your guide.

Wow, that is trippy. Those Rivera instructions look like a carbon copy of the APM instructions, only with Rivera replaced by APM. It's even the same part number! Is the Rivera Pro Clutch a repackaged APM clutch?

Not sure what you mean exactly by "reverse bow contour" on the spring. The only way that I can see that it would work is to have the "dome" of the spring facing outward.

I got a response from Ben Kudon at APM. Not much help, just re-iterating that it is a two finger lever pull. I honestly don't see how one could install this clutch incorrectly, there is not really anything to it. And the parts are even marked which side faces out.
 

Mark, I might take you up on your offer. So you're saying ditch the .120" inner plate and use a standard plate? That kind of makes sense, as it feels like this thing is overly compressed. I'll ping you. Also, I think I will get one of those black diaphragm springs to give it a try.

Oh, and you were spot on. After a couple hundred miles, the thing is now a lot less grabby and easier to feather.
 

thanks,
JW

Rivera shut down. No more. Ben was the guy at Rivera, he formed APM, same building, designs, suppliers, bad attitude, etc.

[turboprop]

There are really two versions of the pro clutch. I will call them, old and new. The difference between the two is the center hub. The old hub had a flat surface that functioned as a steel plate. The new hub does not the flat plate are. Instead it has small nubs that protrude from each of the splines. The clutch pack for the new hub includes a thick steel plate. It goes in first and functions as the plate area that is integrated into the old hub. The remainder of the clutch pack uses the standard steels and frictions.

[72fl]

Rivera Pro, APM,

American Prime is who is Manufacturing them Now.

JW I guess I misworded but the outside of the spring Bow back at you, you could try like a 6" scale to lay across it. Or I guess anything that is flat and you can lay across the spring and measure the deflection. Check Marks out he is why I installed mine. Dave

[FSG]

[JW113]

Thanks Gary! Although that is the video for the Evo clutch, it inspired me to go find the 4 speed clutch as he mentioned.

https://www.youtube.com/watch?v=Wd-ttSzm7Ro

Sure wish I knew how you guys embed videos into these posts! That is a neat trick.

At the end of the day, as you can see, there is not much to this clutch and not any way that I can see to screw up the installation. However, at time 7:25 of that video, I see something quite NOT what the claim is for the diaphragm compression measurement.

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I could drive a Volkswagen Beetle between the gap of that ruler and the outer edge of the spring. .020??? Say what??? What I'm am I missing here?

I'll be giving him a call in the morning...

-JW

[billbuilds]

    That measurement is the compressed spring measurement. I don't see where you are compressing the spring.

[ghostrider]

I don't think he had the 4 bolts tightened down,  it was just for illustrative purposes.  Thats why the gap looks so big.  Why don't you just bend the lock tabs back, then back the 4 nuts off a turn or two and see if this changes the feel at the lever.  If it does, get some shims.

[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. 

[JW113]

Gotcha! And yes, you are spot on with that. It's amazing how the most obvious is so easily overlooked. Right there hiding in plain sight.

"Oh, it CAN'T be that!"

 

-JW

[JSD]

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

Is this the strengthening ring for clutch hub ? 

[FSG]

Is this the strengthening ring for clutch hub ?

Dr Google will tell you it is, it'll also show some pix and destructions.

[JSD]

Is this the strengthening ring for clutch hub ?

Dr Google will tell you it is, it'll also show some pix and destructions.

Thanks FSG as i have a cracked BDL hub, at keyway and fitted a new one to a customers bike so i think i will get it and fit   Strengthening ring. Thanks again mate 

[david lee]

what does that do ?

[kd]

what does that do ?

Go back and read the posts from post #33 on. 

[FSG]

not my pix but ....

tighten the hub too much on the tapered mainshaft OR just dump the clutch to often can result in a hub split at the keyway




fitting a support ring can and does help

[JSD]

I recently installed an APM Comp Master clutch in my '77. It is essentially identical to the Rivera Pro Clutch, and my understanding is that the two were designed by the same guy. While the clutch works, and solved my slipping problem, the force at the lever is off the chart. I called APM this morning, and got essentially zero help. He was convinced that I installed it wrong, or that the cable was binding. If you're at all familiar with this type of clutch, unless you get the disks/plates out of order, there is essentially no way to install it wrong that I can see. Before installing it, the lever force with the stock 10 spring clutch was hardly anything, and I didn't touch the cable when installing the APM. Just for grins, I removed the clutch adjust screw, and the clutch rod moves out with essentially zero effort. It ain't binding. And the cable is teflon lined with a touch of silicone oil. Friction is not the problem.

Also for grins, I used a linear force gauge and checked the clutch lever on my '92 Evo: 8 lbs pull force. Then checked my '04 Road King with SE heavy duty diaphragm: 13 lbs. And the Shovelhead with APM: 32 lbs pull force!

I'm at a loss. Everything that I have read, and what the APM dude told me today, the diaphragm clutch should have much less lever force than the stock 10 spring clutch. It ain't. Much, much more force than the stock clutch. I am at a loss what to do now. Any suggestions, other than pull the freakin' thing out.

-JW

JW is the part no 1056-0002 comp master made by American Prime. It shows a steel inner hub (no cracked key ways) but say for dry clutch use. i am running a sealed primary with oil for primary chain lube. Has anyone used one as in my situation? 

[72fl]

I recently installed an APM Comp Master clutch in my '77. It is essentially identical to the Rivera Pro Clutch, and my understanding is that the two were designed by the same guy. While the clutch works, and solved my slipping problem, the force at the lever is off the chart. I called APM this morning, and got essentially zero help. He was convinced that I installed it wrong, or that the cable was binding. If you're at all familiar with this type of clutch, unless you get the disks/plates out of order, there is essentially no way to install it wrong that I can see. Before installing it, the lever force with the stock 10 spring clutch was hardly anything, and I didn't touch the cable when installing the APM. Just for grins, I removed the clutch adjust screw, and the clutch rod moves out with essentially zero effort. It ain't binding. And the cable is teflon lined with a touch of silicone oil. Friction is not the problem.

Also for grins, I used a linear force gauge and checked the clutch lever on my '92 Evo: 8 lbs pull force. Then checked my '04 Road King with SE heavy duty diaphragm: 13 lbs. And the Shovelhead with APM: 32 lbs pull force!

I'm at a loss. Everything that I have read, and what the APM dude told me today, the diaphragm clutch should have much less lever force than the stock 10 spring clutch. It ain't. Much, much more force than the stock clutch. I am at a loss what to do now. Any suggestions, other than pull the freakin' thing out.

-JW

JW is the part no 1056-0002 comp master made by American Prime. It shows a steel inner hub (no cracked key ways) but say for dry clutch use. i am running a sealed primary with oil for primary chain lube. Has anyone used one as in my situation? 

I run this one and put just enough oil/ATF to touch the bottom of the clutch basket, never any issue's. I think 76shuvlinoff does also.

[JW113]

JW is the part no 1056-0002 comp master made by American Prime. It shows a steel inner hub (no cracked key ways) but say for dry clutch use. i am running a sealed primary with oil for primary chain lube. Has anyone used one as in my situation? 

Yes, that very one. And like 72FL, I run exactly like that. Sealed primary, ATF up to the bottom of the clutch basket, no issues at all. In fact, when ever I take the clutch apart, the plates are essentially dry, little to no oil gets on them. There is really only enough oil for the starter ring gear to contact and throw it around on the chain. Centrifugal force keeps the clutch plates dry.

-JW

[kd]

JW is the part no 1056-0002 comp master made by American Prime. It shows a steel inner hub (no cracked key ways) but say for dry clutch use. i am running a sealed primary with oil for primary chain lube. Has anyone used one as in my situation? 

Yes, that very one. And like 72FL, I run exactly like that. Sealed primary, ATF up to the bottom of the clutch basket, no issues at all. In fact, when ever I take the clutch apart, the plates are essentially dry, little to no oil gets on them. There is really only enough oil for the starter ring gear to contact and throw it around on the chain. Centrifugal force keeps the clutch plates dry.

-JW

And that's the way it should be.

[76shuvlinoff]

 

[72fl]

I just took my Primary all the way down to install a new Main seal spacer from Ray's and a James Supernut. What I don't like about the Rivera Pro is the 4 Button Head bolts that go through the Hub and they tell you to use a lot of Anti Seize on the Nut side to ease in removal. I had 1 when after I Red Loctited it that when I was snugging up the last nut to assembly Spin, so here we go removing Everything again and Pressing out the Hub and redoing the Loctite. After letting it sit overnight and finish the install, I thought to myself they should use a Wheel Stud type Bolt in here with Splines that as you tighten it 1 TIME it will be in there Permanently and if the occasssion arise's that it needs to be removed for some unknown reason stripped thread etc. Press It Out when you Press the Hub out. Done

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[ghostrider]

Under those button head bolts is a great place for Nord-locks

[72fl]

If I ever take it down again that will absolutely be a consideration, the other thing is the Pulley is an alloy of some type, not sure what it is as I was considering other alternatives and threw a magnet on it to see and no sticky as I suspected