Variable Pressure Clutches

[98fxstc]

I looked at the VPC some time time ago and was set to make the buy when I came across references to a AIM 480lb spring and ClutchWiz combo.
The ClutchWiz was developed by a couple of guys on the trike forum where they experience quite a bit of clutch slip with trikes and heavy baggers with hopped up engines and the heavy clutch springs create problems with heavy lever pull.
It reduces the clutch effort by shifting the moving the 'fulcrum ring' inwards towards the ends of the fingers to make the use of the 480 lb spring easier.
It works with cable clutches and hydraulic clutches.

I have a Energy plus 1clutch fitted which slips occasionally under heavy load at take-off.

I have not fitted the combo yet so I cannot verify its use.

[Jim Bronson]

From my research, I don't think ClutchWiz was or is a production part. As you said, it was developed by a couple of guys on a trike forum, and they offered a few to those members for a while. They sound like an AIM VPC ring minus the centrifugal weights. Too bad, they probably helped reduce lever force for not much money.

[98fxstc]

I have one ready to ft, have had it for a while.
Don't know if they are still in production.
There is one on ebay.

[Thermodyne]

I have run the SE VPC for several years.  Yellow 103 spring and Alto carbonite power pack. 

This year I finally over powered the yellow spring in the 2500 rpm range.  SE spring I had on the shelf cured it, but I didn't like the pull effort. 

I switched to a Barnett coil spring VPC.  Ran into some issues because of stack height, but after sorting that out I was able swap coil springs around and end up with no low end slip and less lever effort than the SE diaphragm spring.

[thirdjld]

When your using a VPC can you still "speed shift" ? TIA

[kd]

When your using a VPC can you still "speed shift" ? TIA

As the rpm increases, so does the power it take to pull in the clutch because of the centrifugal force on the weights.  In the higher rpm it can be real tough to pull the lever.

[Coyote]

When your using a VPC can you still "speed shift" ? TIA

As the rpm increases, so does the power it take to pull in the clutch.  In the higher rpm it can be real tough to pull the lever.

Correct and one of the reasons I removed mine and sold it and bought a real clutch. Way too much slipping at low rpms, way to hard to pull at 4000/4500 rpms. Never been a fan of VPCs since.

[kd]

When your using a VPC can you still "speed shift" ? TIA

As the rpm increases, so does the power it take to pull in the clutch.  In the higher rpm it can be real tough to pull the lever.

Correct and one of the reasons I removed mine and sold it and bought a real clutch. Way too much slipping at low rpms, way to hard to pull at 4000/4500 rpms. Never been a fan of VPCs since.

  Bandit and done.

[No Cents]

When your using a VPC can you still "speed shift" ? TIA

As the rpm increases, so does the power it take to pull in the clutch.  In the higher rpm it can be real tough to pull the lever.

Correct and one of the reasons I removed mine and sold it and bought a real clutch. Way too much slipping at low rpms, way to hard to pull at 4000/4500 rpms. Never been a fan of VPCs since.

  Bandit and done.

    yep...   100%
Bandit.

[Thermodyne]

When your using a VPC can you still "speed shift" ? TIA

As the rpm increases, so does the power it take to pull in the clutch because of the centrifugal force on the weights.  In the higher rpm it can be real tough to pull the lever.

Yep. it pulls about like the SE spring when its spun up.

[Hilly13]

When your using a VPC can you still "speed shift" ? TIA

As the rpm increases, so does the power it take to pull in the clutch.  In the higher rpm it can be real tough to pull the lever.

Correct and one of the reasons I removed mine and sold it and bought a real clutch. Way too much slipping at low rpms, way to hard to pull at 4000/4500 rpms. Never been a fan of VPCs since.

That's my VPC experience as well, I went back to the Muller and an LE Harley cable with an SE plate, light enough pull that didn't change with rpm.

[Deye76]

"In the higher rpm it can be real tough to pull the lever. "
For the life of me I never noticed this. Maybe because my clutch was a hydraulic.  My set up was VPC 83T stock clutch, SE spring. Many shifts near the limiter (6200)
"When your using a VPC can you still "speed shift"
I did a lot.

[FSG]

"In the higher rpm it can be real tough to pull the lever. "
For the life of me I never noticed this. Maybe because my clutch was a hydraulic.  My set up was VPC 83T stock clutch, SE spring. Many shifts near the limiter (6200)
"When your using a VPC can you still "speed shift"
I did a lot.

For the life of me I never noticed this.

I know the increase is there but never notice it, heck the lever is only just touched for a split second the change is made and we're under full throttle again

It's not as though your pulling the lever to the grip for a few seconds while at full throttle .......   well maybe some are 

[Jim Bronson]

Well I'll know soon enough. My biggest peeve is having to hold it in while stopped. If it helps with that, I'll be happy. It's a good thing I don't have any health problems with my hands.

[Deye76]

"I know the increase is there but never notice it,"

Then it's not real tough to pull the lever. 

[calgary56]

I'm running an S&S 111" in my '05 Wide Glide, last Dyno I had done said 127 HP, 123 TQ, when I was riding at 120 - 130 kph (74 - 80 mph) and whacked the throttle, the engine would race, THEN the bike would catch up (no tach on a Wide Glide, but you know when you're clutch is slipping).

Had a VPC installed, no more issues with clutch slippage, .... as for the easy pull (cable operated clutch), not the case with the damned thing I have installed, it's a b!tch.

Bought a Barnett Clear Derby Cover off of Amazon, looks good.

[FSG]

as for the easy pull (cable operated clutch), not the case with the damned thing I have installed, it's a b!tch.

that's the SE VPC done by AIM for HD, the colour matches the flames   

what diaphram spring is in there and what clutch cable?

[Jim Bronson]

I've now put a few hundred miles on mine (AIM VP84IV with HD 110 kit and SE spring) The lever pull at idle is much easier, and I don't notice the increased pull at higher RPMs. I'm not a drag racer, so that's probably why I don't notice it. One thing I do notice is that neutral is MUCH easier to find. Never once have I missed it so far, so I'm happy for that reason alone.

[FSG]

Jim   

[calgary56]

as for the easy pull (cable operated clutch), not the case with the damned thing I have installed, it's a b!tch.

that's the SE VPC done by AIM for HD, the colour matches the flames   

what diaphram spring is in there and what clutch cable?

I'm not sure, I'm up at work in the "Oil Sands" at the moment, when I get back home, I'll talk to the shop that looks fter my bike and see what's up.

[jmorton10]

I have an SE VPC kicking around in my shop that I have no use for. It came in a used RK I bought a few years ago & I removed it to install a Bandit clutch.

If anybody here needs it, let me know & I'll send it out.

~John