Missing brake drum sprocket tooth

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Oct 8, 2007
I just noticed on my 72 the brake drum sprocket is missing a tooth.

When I built up the bike I worked on the drum a lot and I can't believe I would not have seen it.

I've put about 600 miles since the rebuild, chain seems fine and in adjustment and teeth don't appear to be unusually worn.

Any suggestions on what the heck could have happened? :|


Same here rx7171. Have a 72 and been missing a tooth for some time. Way past 600 miles and haven't changed the sprocket. Also was told a stone perhaps was the cause. Going to change it some day.
A sizeable batch of inferior Indian-made sprocket drums materialized about twenty years ago--if you've got one the teeth will hook and eventually wear down to nubs, causing dramatic driveline characteristics. If so, return to sender--who is surely not blameless at this late date.

Tim Kraakevik
Three Commandos
I'd put good money on a bet that NO stone could get in the teeth
to matter. I ride THE Gravel, for miles each trip in/off and me
and bike get stoned good. Some will come off front to
hit shin to bleed, also some get traped between frame
and isolastics to make ya think you've hole a cylinder
with vibration till removed.

I'd expect the poor quality and worn chain riding up the teeth.
I'd also highly suggest a look at the tranny sprocket.
Among my used up collection are 4 drums and 3 tranny
sprockets with either, turbo fanned over, missing teeth or just
useless nubbins of drum teeth left.
Likely one tooth gone out of 43 is a non issue, but if
poor metal then best start shopping for future.

There is a sprocket only k replacement available that
is like half again more teeth and OD, I fitted one
as experiment to find impossible to fit with chain
guard on and need extra links in chain and essentially
un workable for a road bike but just the thing for
dedicated hill climber. Available for cheap shipping only.


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