Open Primary Clutches

[Raywood]

Didn't want to hijack JMN's thread on open primary's so started a new one on clutches.
You know guys I've posted in the past that I didn't like open primary's but mostly cause of the sound. So, I'm changing my thinking now primarily (no pun) cause of the improvements they have made in the amount of noise they put out.
Whether it is due to the new style clutch baskets or just the covers they put on the baskets I'm ready to go this route now also.
One of my main considerations is starters. Lots of complaints here on those feisty starters and as many of you know I'm on my 8th or 9th can't remember. Seems a dry primary won't allow oil to leak into the starter where as they will last longer and it's cleaner. Still don't want the noise but.......

One question though. What provides the pressure on the new clutch packs that use a diaphragm vice all the springs on the 8 to 12 studs that the old clutches used?
Where does the lock up pressure come from?

Thanks,
Ray

Old style with all those springs

New style with diaphram

 

[CCRainman]

Ray the black diaphragm is the spring. It's a plate that is has tension. They have 3 different one. The black is light, the silver is medium and the gold is hard. I had to use a gold spring when I put my open belt drive on because the silver was too soft and the clutch was over heating in traffic. I have the Primo and it makes a little noise, not a lot. I had it making no noise but when it got hot. It would stick and I had no clutch. i hope tgis will help you understand the new springs and decide what to get.

 

[Raywood]

That diaphragm is nothing more than a warped plate is it not???
Does it provide the amount of pressure required for these big twins??? Obviously it does just doesn't make sense to me!

Thanks CC

 

[V]

Yea its an "engineered diafram" warped plate. The stock one on my 05 slipped after I had a new exhaust put on so had to go to the next heavier. A guy at the local shop just put in a 600 cam, 040 off the jugs and valve springs. He is locking up and burning rubber with the first soft stock spring and no slipage on the clutch. So I would have to guess that the engineered side of the diafram clutch spring has some give and take as far as tolerence and can't spell


V

 

[LamboV12]

That diaphragm is nothing more than a warped plate is it not???
Does it provide the amount of pressure required for these big twins??? Obviously it does just doesn't make sense to me!

Thanks CC

Yup - and I've had all 3.. the gold one can be a bitch on your hand after a long ride in city traffic. The stronger the plate - the more lever tension.

 

[CCRainman]

Yup - and I've had all 3.. the gold one can be a bitch on your hand after a long ride in city traffic. The stronger the plate - the more lever tension.

Tell me about it. I rode in city traffic for about 45 minutes and I couldn't feel my left hand. I've been using the squeeze thing that you streghthen your forearms with to build up my finger and wrist strenghth.

You can't use the other springs on our bikes because there is not enough tension.

 

[Gas Man]

Your stock BDM primary, at least my 2006, uses a diaphram style... i'd post a pic.. but right now PB is doing maintance..

 

[alhall88]

My primo setup uses the pro clutch (dry version) and it pulls nice and smooth. I would say mine is no different then the old primo clutch it came with as far as tension. The big difference is the machined basket like you said instead of the pins. Mine has zero clutch chatter. All I hear is the belt whine when cruising at slow speeds which to me sounds cool as hell.

 

[dingo]

Same on the Karata.

My Karata started chattering recently at only 1600 miles.....pulls fine - just chatters.....still under warranty so will take it in for a check.

 

[Raywood]

Your stock BDM primary, at least my 2006, uses a diaphram style... i'd post a pic.. but right now PB is doing maintance..

I know we have a diaphragm clutch plate! :argue: What my question was is how does it provide the pressure that 12 springs use to on the old style pressure plates!!!!
And there is a picture of the diaphragm style in my first post.

 

[Raywood]

There is no real answer to that ray Except this, THe Diaphram is a Real Heavy Gage, and contacts a smaller radius of the Clutch plates. The Springs tension is adjustable through different sizes mainly, and more even pressure in my opinion put better crab on the plates which is more power to the ground

 

[Gas Man]

My primo setup uses the pro clutch (dry version) and it pulls nice and smooth. I would say mine is no different then the old primo clutch it came with as far as tension. The big difference is the machined basket like you said instead of the pins. Mine has zero clutch chatter. All I hear is the belt whine when cruising at slow speeds which to me sounds cool as hell.

I can attest to the whine sound... probably a motivator for me to get one...