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B29 BTH Generator Clutch Gear Assembly

Started by cycarmark, 15 Sep 2018 at 21:17

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I had to remove the outer engine cover today to install Helicoils in some of the stripped out holes for the securing screws.  When I got the cover off, I noticed there seemed to be something odd about the generator gear arrangement.  Looking at the BTH pancake generator and the little gear on the back of it, there was nothing inside that would drive it.  Checking the book, it looks like the entire gear/clutch assembly is missing.  Does anyone happen to have one that they would like to part with, or can someone tell me how many teeth are on the gear itself.



Should be the same as the 350EW. See post here:

Note first few images are the larger magneto gear as used on the 600cc bikes, but further in the post are images of the smaller gear as used on the 350cc. Both use the same drive gear for the dynamo.

Pictorial section view:

You should have the magneto gear portion, or at least the housing for the cone clutch, unless the magneto gear has been replace by a plain magneto gear (non-electric model).

You will go to a lot of trouble reinstating the drive only to find the output of the BTH pankcake dyno is abysmal. It might make more power disconnected and as a cosmetic feature, as at least it won't be a drag on the engine! :) 



Thanks Doug, I found this info last night when I searched on BTH pancake dynamo.  It has the magneto gear with the threads for the clutch mechanism and I have a machinist friend who could probably help out making a gear to work.  I'm not sure how I am going to proceed, maybe modern LED bulbs will help with the low output! :D