Auto To Slip-clutch Conversion

[Hal the Elder]

HELLO...

When I rode my first Whizzer in 1951 (a friend's bike), I believe it was a Pacemaker. I do recall the positive feel of the slip-clutch and the braking assist from engine compression in addition to the drum front brake and the rear coaster brake.

When I acquired Oscar 57 years later, it was a new, unsold 2005 NE5 that I bought on November 1, 2008. At the time I had a choice between my blue auto-clutch and another unsold 2005 NE5, a red slip-clutch model, both offered for $1150. Both bikes had 0.7 miles on the odometer.

Whan I asked the dealer a short time later if I could trade back for the slip-clutch bike, he informed me that it was sold! I was just wondering how much trouble and expense it would be to convert Oscar to a slip-clutch bike.

I know I would have to buy a rear wheel with the coaster brake, or keep my present wheel and do without a rear brake, using its hand lever to operate the slip-clutch instead.

Thanks...
HAL

 

[KilroyCD]

Hal, being that I'm an advocate of the slip clutch, I'm not going to ask you why you've made the decision to switch. (However, I'm sure someone will.)
I looked on Whizzer's site, and they have all the parts to change to the slip clutch system. I'm sure some of our dealers have those parts as well.
Regarding the rear wheel, is Oscar a 24" or 26"? If he's a 24", I may have a rear coaster-brake wheel with a black rim available soon.

 

[uncle_punk13]

After having worked on a customer's bike with the auto clutch ( my Whizzers all have only had the slip clutch), it only reaffirms my belief in the slip clutch. It should be a fairly easy conversion for you; and please find a coaster wheel, as running with no rear brake can be disastrous... No contest IMHO- it's a better set-up.

 

[Hal the Elder]

Thanks, Gentlemen!

I'm not absolutely certain if I would be willing to go through with such a project, because of the expense of a new rear wheel with a coaster brake, plus the clutch and control linkage. This sounds like several hundred dollars!

However, the resulting "solid linkup" drive would be what I've been wishing for, and the actual work in doing the project would be enjoyable!

Oscar is a 26" bike, Chris.

HAL

 

[Quenton Guenther]

Hi Hal,
I have a lot of the slip clutch parts in stock and would gladly sell at a reduced price. It is important to note, setting up the slip clutch requires a lot of talent. It is much more difficult to arrive at a setting that will let the bike stop without "killing" the motor, of if adjusted to release when stopped not slipping while in motion.

The slip clutch loss a lot in the translation from vintage [works perfect]to the new edition version. The clutch arm isn't the correct length and the belt normally rubs one of the bottom belt guard posts. The original Whizzer clutch handle has more "throw" and moves the arm a lot more than the current version. The solution is to spend another $75.00 for a belt tension kit to make it all work better.

Before you make the change, understand you won't be a "happy camper" in the process of getting it working correctly.

Most of my vintage collection use the slip clutch, however all but one of my new generation Whizzers are automatic. I like most, prefer the slip clutch, but on the new generation models I find it easier to cope with the automatic.

Have fun,

 

[Hal the Elder]

HEY QUENTON:

I'm getting more confidence as I work on different systems on my NE5. Indeed, I've found that making the mods is as much fun as using them!

I know my big expense will be the 26" rear wheel with coaster brake, and I would want the wheel with the spoke flanges as part of the brake hub, rather than the type with the "pressed on" flanges. I want as much reliability as possible with Oscar transporting my 225 pounds over uneven desert terrain!

Would the belt tension kit make the engage/release action more like the vintage Whizzer?

What would be the total cost of the project, including the 26" wheel with coaster brake, the clutch and linkage, and the belt tension kit?

Thanks! (I could spend my tax refund on the project, I guess!)

HAL & OSCAR

 

[Quenton Guenther]

Hi Hal,
Yes the tension kit will make it work more like the vintage version. I will try to arrive at a price for the needed parts on the clutch system, and I might have a used tension kit somewhere in my stockroom to aid in keeping your costs down. As far as the wheel is concerned I can't be of much help. It would most likely cost a lot less to have a bicycle shop install a good coaster brake hub in your current wheel.

I might even consider trading your current clutch parts in, but only if you are 100% sure of the change over.

Have fun,

 

[Hal the Elder]

HEY QUENTON:

I really appreciate your willingness to help me out with costs!

My bike shop would probably have to lace on new 0.108" spokes to fit the coaster brake's flanges, unless the existing spokes can be used.

I'm excited about the prospect of having a slip-clutch Whizzer, as long as the components will take the stress of a "hotter" engine.

As soon as I get cost information from my bike shop on fitting a coaster brake to my existing wheel (and if it's affordable), then I'll give you the go-ahead and send you my auto-clutch.

HAL

 

[WZ507]

Whizzer Manual Clutch

Hal,

I realize you are riding in a relatively rural area, and likely will never encounter the scenario below, but nevertheless wanted to alert you to potential issues with manual clutches.

So, on your question regarding the manual clutch handling the hotter engine, there can be issues. When you create an engine that makes some real power, many people feel the stock gearing is too low and often opt for higher gearing (replace the stock vintage clutch size having input/output diameters of 5" x 3.5" with the stock 24" bike size of 5" x 4"). Having the higher gearing in turn puts more demand on the clutch. This is all fine and dandy until one day when you go on a slow ride with a large group in hot weather in stop and go traffic. All the slipping associated with starting from a dead stop ends up as heat dissipated in the belt and flywheel pulley. Know what happens to a really hot belt? It softens and becomes even more sticky, drags severely, and engages dramatically with an awful screech. This is an intensifying viscous cycle that always ends the same - ever more clutch drag and a broken belt - it's ugly!

On the contrary, the friction material in the auto clutch is a wonderful thing - it doesn't really care whether you are starting or stopping, how the bike is geared, what the temperature is, etc. It can tolerate whatever you throw at it.

If you have a manual clutch and you intend to slip the daylights out of it you may want to try one of the green Gates PoweRated belts. This belt differs in design from a standard A or AX series belt, in that it has a higher fiber content (face, sides and back) and doesn't have the raw rubber edge exposed as do the A and AX series belts. It can take much more clutch slipping before it overheats.

Not trying in the least to sway you one way or the other, simply providing perspective that may not yet have been factored into your thought process.

 

[Hal the Elder]

HEY WZ507: (Is that a Ham call?)

Thanks for alerting me to the possible pitfalls of a manual slip clutch!

I realize that all the frictional heat is dissipated into the belt and pulleys, rather than the shoes as in an auto clutch. I recently replaced my Asian belts with higher quality Goodyear belts.

But my riding experience is unique:

I ride where there is almost zero traffic and no traffic signals, with only an occasional stop sign at a crossroads. I don't ride with anyone else, so I'm not required to "keep pace" with anyone.

I'm strictly a "lone wolf" rider, setting my own pace during my short (10 mile) rides, all within 5 miles of my home, and at moderate speeds of mostly 20-25 MPH, with an occasional foray up to 30, which I never maintain for long.

With a manual clutch, I would "dump the clutch" early at just over idle RPM to avoid as much slipping as possible. Since I never have to "get out of someone's way" behind me, I'll be happy to just chug off at low RPM and leisurely accellerate ro my comfortable cruising speed of 20-25 MPH. This is the stress-free beauty of riding in no traffic!

I increased the power of my NE5 only to compensate for the power loss due to my elevation of 3000 feet, where the atmospheric pressure is only 13.16 psi.

I'm still interested in going to a slip clutch, and many on this forum also prefer it.

My "hotter" engine is really not that hot, considering my elevation...probably not much hotter than a stock 1.95HP whizzer at sea level.

Thanks...
HAL