Belt final drive for EZM Qmatic

On another thread we have been discussing, debating, speculating about converting from chain final drive to belt final drive...

http://motorbicycling.com/showthread.php?p=595440#post595440

...trying to figure out what is doable and what isn't.

For years I've been interested in the old Whizzers and have wanted to do a belt drive build. I'm in the middle of one now on a thread called "kindalikeawhizzer" which involves a 1951 Schwinn cantilever frame, a flathead 5 horse Tecumseh engine, CVT transmission and Whizzer sheave at the rear wheel. It is in the spirit of the old Whizzers and modeled after msrfan's brigs builds.

But the subject of this new thread has more to do with the thread I have a link to above than to my current build. A year from now I want to do a serious upgrade to another bike, this one a 1950 Panther currently running a 99cc Predator coupled to a Q-matic transmission with chain to sprocket final drive. Since it is pushing a sidecar I want to give it more power and have in mind a 147cc 2 stroke Jacobsen engine from the 1970s. I intend to use it with the Q-matic tranny. I'd like to change the final drive to belt as I like the look, understand that it is quieter, smoother and is certainly cleaner. This desire to make the final drive conversion is what attracted me to the linked thread above, trying to figure out how to go about it.

I just learned from my friend Tinsmith (another Q-matic user) that it has already been done by the guys at EZM. I did some looking around and found a picture from a rival site which shows a build from Helmut with the Q-matic and what appears to be a Whizzer sheave on the rear wheel. I read of a 3" drive pulley and initially of slippage problems at the drive pulley using a standard V belt.

I know there are a number of people on our forum who use the Q-matic transmission and wonder if any of you have made the conversion to belt drive? If so, what was involved, how much did it cost, were alterations to the frame needed and how has it worked out? Can anyone lead me to more information? As always, thanks for any input.
SB

Thanks for your comments, Racie. On my Kindalikeawhizzer build I'm using a knockoff of the comet TAV transmission and am glad to hear of how well yours works. And good to hear about the 2" pulley working.

Regarding the Q-matic conversion, which I want to use on the panther upgrade since I already have it, seems to me that it should work okay, too, with a 3" pulley. Good point about alignment. Are you using an idler pulley against the belt going to the sheave?
SB

What is the diameter of the drive pulley on a Whizzer motorbike?
SB

Bill,
Thanks for the link. I've sent him a message and hope I get a reply. I also sent an email to EZM, but haven't heard back yet. How's life out there in sunny Arizona? Still giving the grandkids rides in the trailer? They must be getting big now. Maybe they give Grandpa Bill rides while you sit in the trailer.
SB

Brown,
Thanks for the link. Terry does like to talk. He said the drive sheave is "almost 4". And it certainly looks like a Whizzer driven sheave on the wheel. Thank you, sir!
SB

I got the following links from Measure Twice regarding the max torque pully clutch...

http://www.maxtorque.com/html/pully_clutch.html

http://www.mfgsupply.com/4-865.html

Also, this is the other thread where we are discussing belt final drive in a more general way... (not specific to the EZM Q matic conversion).

http://motorbicycling.com/showthread.php?p=596048#post596048

If I remember right the q matic uses a max torque clutch. A question for us is if we are going to need a whole different clutch (pulley clutch) or if we can purchase just the pulley and use our original clutch. I'm hoping we can get by with just buying the pulley to save some money. Could we be so lucky? (Probably not...)

We are, however, getting more information and that is good.
SB

Brown said,
"I want to do the same type conversion as you are working on. However I want to use the idler on the transmission as the clutch and operate the idler with the clutch lever and omit the centrifugal clutch all together.

Ideally I should be able to pedal start the motor and not have the clutch drum noise. Also if the recoil should fail you at least have a backup."

I'll be interested to see how your idler as manual clutch idea works out. I have a similar plan to use an idler pulley as manual clutch on a 3 speed Villiars 98cc engine (1934 Elgin Velocipede) and want to use a china girl type of handlebar clutch lever & cable to operate it. Engine starting on that one is by hand crank made from a ratcheting brace.

Another benefit to your idea is that it frees up some room on the backside of your Q matic transmission with the max torque clutch gone. All you need is a pulley there which gives you some latitude in pulley diameter. Do you intend to use the Whizzer sheave? I hope this works out well for you. Hurry up and do it, be successful and then maybe I can do what you did without any wrong turns along the way. Ha! Are you planning to use a lever type control at the handlebar (like what I described earlier) or some sort of shift type lever with a gate to hold the lever open when you want the idler disengaged? I wish you the very best in your endeavor and hope you will report back whichever way it goes. Even failures inform.
SB

Brown,
Sounds like you've given this a good bit of thought. I hadn't thought about the need for belt guides. Didn't think about it for my Elgin Velocipede either. Back to the drawing board.
I'm still hoping that the existing max torque clutch can be adapted with a pulley to replace the sprocket. That would be the simplest way for me to go on my American Flyer with the 99 Predator and Qmatic. No belt guide issues, either. I'm still waiting to hear from EZM. Nothing so far.
SB