Wednesday, July 27, 2011

Hojo and the case of the sticky clutch

Background

So, no shit, there I was.  I rebuilt the clutch on my P200, following the excellent Youtube video by Scooter Mercato, and also consulting the page on Scooterhelp.  Unfortunately, my clutch wasn't working after the rebuild.  I'd pull the clutch lever, but it was as if the clutch wasn't doing it's job.  If I was in gear, the wheel would remain locked to the engine.  I spent several evenings trying to sort out the problem until I finally hit upon the issue and solution.

The CliffsNotes
I had the brass spacer washer in upside down.


The Details

The clutch in an injected P200e like mine presses up against the injector gear.   In this picture, I've marked the injector gear with red slashes where the clutch presses against it.


Here's the side of the clutch where it goes into the engine.  You see the complementary red marks on the part of the clutch that is driven by the engine.   The blue marks on the outer gear indicates the drive gear of the clutch.  This is the gear that should NOT go around when you have the clutch lever depressed.


The crux of my problem was that I installed the brass spacer washer in the clutch upside down.  In this photo, you can see me installing it correctly, with the concave portion upward.  It was illustrated this way in both of the clutch rebuilding sources I referenced above, but I didn't notice.  


And here we see the problem.  With that brass spacer installed upside down, I held a straight edge across the top of the clutch and drive gear.  The yellow line illustrates where the clutch would be sitting flush against the injector gear.  Notice that in this picture, the red lines for the clutch are pressed up against the injector gear line, but the blue line for the drive gear is ALSO pressed up against the injector line.  That means that there is friction between the injector gear and the drive gear.  Even when I released the clutch, the friction against that injector gear was causing the drive gear to rotate.


So, here is a picture with the spacer properly installed.  You can see that with the spacer installed this way, the drive gear is about a millimeter lower.  It doesn't press up against the injector gear, and is free to spin independent of the engine.

So, after three days of scratching my head before I discovered the problem, the fix was simple.   I flipped over the brass spacer, and life was good.

Hopefully someone in the future will benefit from my anguish!