OK, So What's The Problem?

Hal the Elder

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Hello...

This morning I warmed Oscar up and rolled him off the stand onto the level asphalt road that runs by our house.

I opened the throttle about 1/3...nothing. I opened it wider...and it began to creep forward. Becoming disappointed, I then gave it full throttle, and it slowly accelerated to 10 mph after about 1/10 mile.

Then I took him to a straight stretch of road and tried an acceleration test.

From a standing stop, and with the engine roaring at full throttle, it took 1/4 mile to reach 20 MPH, and it looked like it wouldn't go any faster!

It was as though the drive belt had been greased!

What could be the problem with this here MotorBike?

HAL
 
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M

MotorbikeMike

Guest
Belt or clutch slipping

Hello Hal, well if you have no trouble with the engine being "engaged" when you are starting it, then the only thing that could be is that the clutch shoes are too "slippery".

Some of the shoes were made with a kevlar base which is very long wearing, but a bit difficult to break in.

SO:
pull belt guard,
"roll off" rear belt,
unscrew clutch belt,
remove clutch ( do NOT drop it, it IS heavy)
split clutch by rotationg and pulling in your hands
inspect clutch shoes
if not in full contact with the drum (read the shiny parts, those are working) then take a Dremel (or equivelent) and sand the shiny parts down a little,

re-install
repeat as needed

should work fine when you get 75%+ of engagement.

The shoes were not arc-ground at manufacture, and this is the fix.

Mike
 

Hal the Elder

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Hey Mike:

Is there some kind of rachet in the centrifugal clutch that allows a solid lockup engagement in one direction (like when I'm pedal-starting it), but slips when the engine is driving?

I also notice that with the engine shut off, I can wheel the bike backwards and it's "free-wheeling", with no connection to the engine, but when I move it forward, I must use the compression release or the rear wheel skids from the engine's compression.

There must be some kind of "one way" rachet in there...right?

Anyway, thanks for the fix tip...I'm always looking for an excuse to dig into something mechanical anyway!

HAL
 

RdKryton

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Yes Hal the clutch has a one way bearing. It will freewheel in one direction and lock in the other. Mike is correct. Carefully remove the clutch and sand down the shinny spots on the clutch shoes. This is a good time to make sure the bearings are greased well.
Jim
 

Hal the Elder

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Ok Mike, So How...

So how do you "roll off" the rear belt?

There's too much tension on both belts from the tensioning spring.

Could I peel the drive belt off the rear wheel sheave instead?

Then how do you remove the clutch with the tension from the engine belt on it?

(This is great...a brand new Whizzer and I have to tear it down to make it run right...I should have bought a USED bike!)

HAL
 
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sk8erpunk

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Hal, I know it is a pain. I had issues with my brand new bike, too, but .... these are really minor issues. I didn't think I could even deal with the clutch, but I found out that all of these things are really simple and easy to deal with (including the clutch). Just be careful (as everyone says) but don't sweat these little things. It is part of the break-in process. And you will be fine.
 

Hal the Elder

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Oct 20, 2008
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Hey Skaterpunk:

A motorcycle friend (he has a GoldWing) advised me today not to leap in and try to fix something that may only need breaking in.

He said to just ride it and put on the break-in miles and let all the components adjust to each other.

I was having trouble with starting Oscar...now he starts fine, and I didn't do anything!

Maybe the clutch problem will fix itself too!

HAL
 
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Quenton Guenther

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Hi Hal,
Here is a lot of important information on the Whizzer automatic clutch. It is possible to acheive "quick" and "total" lock [my dirt track Whizzer will easily pull wheelies, ask around for pictures], but that isn't the way it normally works. Because of the design, the clutch "slides" into lock, and normally slips when first engaged. If you advance the throttle quickly before the shoes are mated with the hub it will glaze the shoes and the only fix is to remove the glaze [Dremel grinder with a sanding drum] from the shoes. Problem is, once the shoes are glazed it will continue to slip. There were many different version of the shoes used in production, however the object remains the same. The more of the shoe you get to mate with the hub, the better the engagement. My hi-performance Whizzers have 99% to 100% contact, and some of the production clutches start out at less than 15%. I will tell you how I speed up the mating surfaces, but I don't suggest you do it this way. I lock the brakes, open the throttle until the clutch "smokes" a little, then re-surface the shoes [remove only the glazed area on each shoe], and repeat this process until most or all of each shoe is glazed, I then remove the glaze, and the clutch works really well. I would guess if done easily [not my way] it might take 20 or more times to reach 75% contact on some versions of the clutch. It is also important that you don't use my method on some of the earlier versions of the clutch because it could end up with undesired results. On the very early [all out of warranty by now] versions of the clutch, the shoe pivot pins didn't go all the way through the hub [hub was cast iron], and some of the pins could pull out of the hub, and I don't need to go into detail about the possible end result. The next version still used the cast iron hub, but the pins were pressed all the way throught the hub, but some still ended up with loose pins because of the way the pins were "peened" on the hub [most, if not all, are now out of warranty]. The next version still used the cast iron hub but the pins were flattened at the exit point on the outside of the hub [most, if not all are now out of warranty], as far as I know none of the shoe mounting pins ever worked loose on this or any future version. If the pins are loose on the earlier versions, a simple fix is possible. I am still using one of the earlier versions on my 1999 Whizzer that I modified to correct the loose pin problem. If the version doesn't have the holes all the way through the hub, drill the hole through with a 13/64" drill [can get away with using a 3/16" in a bind], then thread with a 1/4" X 20 tap. Next purchase 1/4" shoulder bolts, so that the shoulder matches the length of the hole in the shoe [may need to open the hole in each shoe if the fit is too tight to pivot], then thread the bolt throught the recently cut threads, and use a 1/4" X 20 nut to "lock" the bolt in place, cut off any extra threads extended past the jam nut. If the holes are already through the hub with loose pins, you just skip the part about drilling the hole through. Next I will cover the shoes used during the process, but it must be noted many of the similar style clutches [not Whizzer] with shoes on a pivot didin't have any material on the shoes, but were metal to metal contact. The shoes on the earlier Whizzer clutches had a very thin, but wider contact surface bonded [glued] to the shoes, the later versions added a thicker contact material, but weren't as wide. Some of the shoes had material attached with a taper cut, and some were cut even, therefore some took longer to "mate" with the hub than did others. It is important to note that my 1999 model is using the shoes with the thin, but wider shoe material, and it "hooks" up really well [over 68 MPH on a dyno]. The clutch on my dirt track racer uses the later clutch with the aluminum hub, and the shoes with the thicker but narrow material, and it can pull wheelies [works very well]. Another important change in the Whizzer clutch system concerned the bolt that mounts the clutch to the arm, the early version used regular threads, but early in production the mounting bolt was changed to reverse threads. It is very important that you know which version is used because if over tightened the bearing centers could be crushed and destroy the bearings [#6901Z available from any bearing company], Whizzer installed a sleeve between the bearings, but it isn't strong enought to overcome the power of a good socket wrench [not their fault we are so strong]. Later versions of the clutch added more bearings [some used as many as 5 instead of 2], however I prefer the version with only 2 bearings because the hub structure is more solid on both ends of the bearing sleeve area, and I now have a couple in my collection with the bearing race snapped from the hub [ a problem I doubt many will ever see]. Most of the Whizzer automatic clutches used a 3 section bearing and a seal on each end [my favorite version], but the latest editions removed the seals, replaced the 3 section needle bearing with a single one-way version, and installed a larger caged bearing on each side. Recently I modified 51 clutch hubs [installed a rockwell 58 rated bearing sleeve on each], and found the bearing surface in many different configerations. Some of the bearing surfaces were cast iron with no bearing sleeve, some had a bearing sleeve installed, but looked like it was cut on a lathe [rought tool marks], and one had a hardened bearing sleeve. All of the clutches I rebuilt were out of warranty, so I will gladly furnish the needed information if anyone wants to upgrade their own clutches [as a few have already done]. The bearing sleeve is 38.5 MM long, the O.D. is 30 MM, and the I.D. is 25 MM and needs to be high quality, highly polished, and rated at rockwell 58. On the hubs with sleeves installed, the sleeve needs to be removed [slow process on the lathe], but an additional 1 MM must be cut from the remaining surface in order for the new sleeve to be installed. The fit needs to be at least .002" interference and should be installed with a high grade retaining loc-tite [I use # 620 or #640]. It is also necessary to shorten the sleeve on both ends prior to pressing it on the hub [reduce from 38.5 MM to 36 MM].
One of the most common problems is the clutch not engaging during forward movement of the rear wheel. If the one way bearing dosen't lock on the sleeve it is impossible to start the motor [unless you own a Ambassador with the electric starter]. I have found several reasons for the clutch to "forget" to lock the one-way bearing. The most common is the bearing sleeve, the second is a defective one-way bearing, and lastly the single section one-way bearing slipping inside the aluminum hub [only on versions with the caged outside bearings]. I suggest the bearing sleeves be replaced on all versions of the clutch [problem #1 solved], replace the defective 3 section bearing with a new one [problem #2 solved], and remove the single section one-way bearing from the aluminum hub, using a sharp punch, dimple the area inside the hub where the bearing normally resides about 20 or 30 times, install red or better loc-tite, press the bearing back into the hub, be careful to insert correctly or the bearing will work in reverse [problem #3 solved]. These upgrades can be arranged through your local machine shop, some Whizzer dealers, or check in the vendor section for other options.
Because of the changes during production, it is impossible to expect all versions to react exactly the same, but It is very easy to like the way it works with the flat head Whizzer motor.
This post is not intended to discredit any company, person, persons, suppliers, or vendors in the USA or any foreign country, but as information to aid in adding longer life to some automatic clutches.

Have fun,
Quenton
 
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