Ever seen a sprocket like this?

I found this off an old Laura M56 engine (Batavus/Trac), that had been modified to not use the famous toothed belt. Cool farmer-john mod since the carb comes off easily now.

I can't figure out how to get the sprocket off, though! If I immobilize the sprocket and turn the nut at the other end of the shaft, I can actually spin the shaft underneath the sprocket. That means it's not welded to the shaft, and any Woodruff key is broken. Still can't pull it off, though (and thus can't remove clutch or crack the case).

There's a little screw sticking out the side of the back, which you can see in the 1st pic. I filed a notch in it to try to screwdriver it, but it seems to be fixed in place.

Anyone seen one of these sprockets before, or know how to remove it?

Re: Ever seen a sprocket like this?

Those look like sprockets from a derailleur bicycle gear set that has been disassembled from the carrier so there are individual gears. If you can not get the grub screw to loosen on the back of the hub it is welded to, you might have to drill the screw out. If it is a proper grub screw and not just a bolt then the tip will be tapered, so you can drill it out undersize and after try to get the remainder of the screw with an extractor.

Probably need a 3 jaw gear puller to remove the sprocket from the shaft. Little propane torch on the union between the sprocket and the shaft would be a goodly idea.

Re: Ever seen a sprocket like this?

Thanks for the tip, Rebel, I'll try drilling that nut out right away and report the results.

Re: Ever seen a sprocket like this?

hey, is that a homemade tube amp, kit or all from scratch?

Re: Ever seen a sprocket like this?

Impact driver with a allen wrench got the nut out, tapping a hammer on the shaft while holding the sprocket got the sprocket off, and torch + hammering the shaft + holding collar with a 15mm wrench got the inner collar off. Thanks for the help. If these guys could be made easier to attach/detach, this might be a good solution to M56 belt woes.

The tube amp was from a kit: S5 Electronics tube amp kit . I'm saddened to see their prices have jumped a bit, though, but it's a solid amp and a fun project.

Re: Ever seen a sprocket like this?

Like rebel said, those are cogs from a bicycle derailleur that have been brazed to the clutch/pulley hub (pretty clever).

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