clutch slip

Discussion in 'Whizzer Motorized Bicycles' started by old whizzer, Sep 8, 2008.

  1. old whizzer

    old whizzer New Member

    have had a model H for many years recently bought an NE5 with 400 miles on it and am disapointed with the clutch. have deglased with a dremel as described in other posts with minamal improvement is there a way to get the clutch to lockup and hold on a grade. any help would be much appreciated
    Thank you

  2. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Old Whizzer,
    It is going to be difficult to compare the smooth operation of a vintage Whizzer clutch to the current system used on the new edition Whizzers. The problems are many, but I will gladly help you make it work better. The first modification concerns the alignment of the belts. In order for the clutch to have a chance of working correctly the pulleys must have a straight path, and that usually isn't the case, mainly because of the loose fitting clutch arm at the rear of the motor. In order to keep the clutch at a workable angle Whizzer suggests you tighten the arm mounting bolt tight, which stops the movement of the arm and negates the purpose of the spring. Since the rear sheeve isn't completely round and is very seldon installed in the center of the wheel, the arm must be left loose to compensate. Another problem is the different arms used in production [not always the same], and often they must be milled to allow the clutch assembly to move closer to the motor to acheive better belt alignment. The new generation Whizzer has 2 bushings in the rear of the motor with a 12 MM I.D. and they use an off the shelf 12 MM bolt, which has an O.D. of 11.8 MM, allowing the arm to tilt outward [because of the pull of the front belt]. For many years I pleaded with them to make the arm the right length, and to use the correct pin or bolt to make the arm stable at the rear of the motor, but it wasn't at the top of their priority list. The solution is a very easy fix, simply purchase a 1/2" shoulder bolt long enough to fit through the arm and then the motor. The bolt must be downsized, the area near the head of the bolt should be cut down to .475" where it resides in the arm [press fit], and the balance of the bolt should be cut to .471" to fit the bushings at the rear of the motor. When this change is made the arm will no longer move sideways, just a smooth up and down motion [just like the trunnion pin used on your vintage Whizzer clutch]. Once the belts run straight, the pull is even on the clutch assembly, and allows the clutch to work much better. Some of the automatic clutches supplied by the new Whizzer company only have shoe contact of approx. 15%, so I usually hold the brake on, open the throttle to cause the shoes to glaze. I then use a Dremel grinder with a sanding drum to remove the glaze, I repeat this process several times until almost all of surface [85% to 100%] of the shoes are contacting the drum. When riding the bike I let the clutch engauge and them back off the throttle slightly to allow full contact, and then open the throttle to the desired speed. It is possible to make this clutch work very well, but it will take some time and effort to make it like it should be. I was told by a person at Whizzer that they were planning on "mating" the clutches prior to supplying them to the public, but it might just be another "rumor".

    Hope this information is helpful,
    Last edited: Sep 8, 2008
  3. old whizzer

    old whizzer New Member

    Checked clutch alignment it tilts outward enough to see without a straight edge
    the clutch arm has an elongated hole where it bolts to the engine I don't see how another bolt no matter how well it fit could hold it straight. would filing the clutch arm where it fits on the block help?

    checked the shoes in the clutch and have 90% contact
  4. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Contact you local dealer and order a new arm [without the slotted hole], because it is next to impossible to make the slotted arm tight. The clutch will work much better if in alignment. As long as the clutch runs at an angle the shoes won't swing outward with even force. There are several dealers on this site that can help you obtain the parts you need to make the clutch work. I guess it is possible to grind the arm at an angle to help correct the alignmnet, but be careful because the arm with the slot is more likely to break than the other versions. And I can tell you from experience that the plastic belt guard does very little to contain the clutch assembly during a major failure.

    Have fun,
  5. old whizzer

    old whizzer New Member

    Thanks for the info will order a new clutch arm and follow instructions to fit the bolt.

    Thanks again,
    O W