Whizzer Slipper Clutch Improvement

Back when we had several local Whizzer rides a year, I joined maybe a hundred people for a nice long journey through Orange County. Some of the bikes had automatics. I didn't. Frequent adjustment of the primary belt cover became a way of life. Getting it not to rub the pulleys and release the belt so you could idle at a stop light wasn't easy. I found that a large amount of my fellow riders experienced the same frustration. I tried strips of metal pop riveted to the inside of the cover and it helped a little, but didn't really solve the problem. I finally went with automatics. They had their own problems but not like a slipper clutch. Much nicer to ride.
So, the other day I decided to try to figure a way to make them more user friendly.
The problem is the cover is so large, it only addresses one side of the belt, the top or bottom, depending if you have it adjusted up or down. Add an easy glide and there's even less movement to release.
That's when I got an idea for a belt guide narrow enough and the right shape to contain both sides of the belt. I started with an actual size drawing of my pulley locations and the guard mounting bosses.



Wanting something that doesn't show, I realized there's very little room to work with. I chose thin gauge sheet metal I had laying around (about .030"), and bent two edges over at the angle of my belt.


Then I fit it onto the pulleys and cut it to size, marking where the mounting holes are.

Before I started on this project, I installed two stationary guides that did almost what I wanted. Their problem is that when the clutch it disengaged, the belt is pushed into the bottom guide making it grab again.



This made me understand the guides have to move with the rear pulley. If I attach the rear of the guide to the bolt head retaining the double pulley, I still need a place to support the front. That's when I made another piece that bolts as the original guard and continues forward. I can make another pivot to hold the front of the guide. The front will need an elongated hole so the guide slides in it because when engaging the clutch, it moves forward slightly.



That meant I had to cut a hole in the center of the guide to accommodate the mounting and movement.





installed it onto the bike and was fairly happy with how it fit.

Finalized the shape and put a little joggle in the mounting piece to line up with the guide and made a stepped rivet to hold the two pieces together letting it slide forward and back.






Next I made a pivot that is held onto the head of the pulley bolt with 3 set screws and holds the rear of the guide retained with a snap ring.






I also made two aligning pins to screw into the guard mounting holes. My guide will slip over the pins with the guard on top and the other 2 screws will hold it all. The pins come out and the 2 remaining screws go in.



That's as far as I got.
Still don't have a clue if it will work.
I'm not real familiar with the newer Whizzers or if this will benefit them.
Let me know if you've had similar slipper clutch problems and what you tried to remedy them.

I'll try to get it installed this weekend for a test.

Thanks Curt. I went to Donut Derelicts this morning and three later Whizzers showed up. The owners said their slipper clutches worked fine, but watching them leave told a different story. One was started on the rear stand and died as soon as he put wheel on the ground. He had to pedal start it on the pavement to get it going. Another guy actually ran along side his and mounted it like a galloping horse, squealing the belt for about a block. The last guy said his will usually stay running while stopped if he keeps the rpms way up. That tells me that all Whizzers could benefit from a better slipper clutch. The hand levers just don't move the double pulley enough to keep the belts from grabbing without perfect adjustment. Add a little wear in the pivots and the pulley also distorts when the lever is pulled. Loose and worn cables also take up movement that should go directly to the clutch.

Keeping in mind the initial intended use for the Whizzer kits, they were offered for younger people as an entry level motorcycle and to enhance the range of delivery transportation, like paper routes and general stores. In the war years they were ridden by factory workers to offset gas rationing expenses. Roads weren't as good as today (in some places), traffic was a lot lighter and stop signs not as plentiful. I don't think it bothered young boys having to pedal start often as much as it gets to us older guys. As their popularity grew, automatic clutches were an option at a reasonable price. Now auto clutches are hundreds of dollars. We ride them for recreation and going out on the busy streets makes the need for a well working clutch more important.
I don't know if my efforts will be successful, but it's fun to try and rewarding if it works. So I'll keep plugging along for a while.

Thanks Ray. I should have checked with you before I started this project. I like the fact that I was on the right track with my design. I'm still trying to take it a step further. Looks like eventually it will work out fine. If I cut my sides shorter, It may have the same effect without so much rubbing. I'll post the results. Also, my front sliding pivot hits the flywheel nut. Relocating or re-designing will fix it. I also like the notched belts (the AX series), and I know what you mean about critical adjustment and belt selection. Been adjusting ever since I got my first Whizzer about 25 years ago. I had a NOS green belt that I wanted to use on this one.

Good job on that lawn tractor Curt. I had a Sears 3 speed a while back and should never have sold it. I'm sick of the newer home use models, with their too light gauge sheet metal, too small fasteners, weak spindles and axles and way too much plastic. I have a small 1959 Bolens in pieces. May get it going soon.

Thanks Ale, I've always tried to give every part a finished look, whether it's visible or hidden deep in the mechanism. No matter who can't see it, you know what's underneath. My job requires working on a lot of industrial equipment, so I see some ingenious ways to get power or movement from one point to another. But the most I ever learned was from working with farmers, truckers and oil field guys. They could fix anything.

Thanks Ray, I didn't get too much info from the owners. One guy owned 2 of them and another the third. I'll see them again for sure and find out what's going on. If they have belt guides, they should start easier and take off better. You're probably right on with poor adjustment and worn belts.

I figured a way to keep the front pivot from rubbing on the flywheel bolt. I opened up the hole and wrapped it into the other piece like a grommet, still having the proper movement.





It fits pretty well and I can now stop whenever I want without killing the motor. Some more testing this weekend, but I'm calling it a success for now.

Clearance is good on the bolt. It may not be necessary with a home made clutch, but would probably help it to release completely.
I did the fender notch when I originally built the bike.

My Bolens was a ride-a-matic, but the engine and trans are missing. I found a replacement engine but may never have the trans. I can rig something up to make it go.

curtisfox said:

Just what model is it mabe I can find a trans around here?

Gard is really looking good........Curt

Click to expand...

It's called a Versa-Matic and is made up of coned sheaves. May be particular to Bolens tractors only. Thanks Curt.