EW350 Back sprocket

[Ken Rogers]

Hi  All
         Can anybody tell me if it is possible to change the rear sprocket on the rear brake drum of my 1926 EW350. Is it all one casting or is it shrunk onto the brake drum ,has any body else all ready done this job and if so how?
                                                                                                                    Many thanks
                                                                                                                        Ken Rogers (Durham)

[Doug]

Ken,

It should be a formed heavy sheet metal drum, and the sprocket is silver brazed on. If it is a cast drum (spokes will be laced to the hub rather than the back of the drum), then someone has put a later wheel in the bike. In that case, the sprocket is shrunk on. Assuming they did the same as the later Aero models, the outside of the brake drum will have a straight knurl to give it more bite under the sprocket, and there are three or four keys a half inch long (if I remember correctly) pinned and brazed to the brake drum just to make sure the sprocket does not slip around. The sprocket has mating notches to slip over the keys.

-Doug

[kev]

doug

 my brake drum has the spokes in the drum...
  the sprocket...just have to heat and press off???...I have a bit of a furnace, an old gas cooktop with bricks arranged to size of item...

[Ken Rogers]

Hi all, just as a follow upon this job the back sprocket is held on with soft solder (thanks Clive)As there is no solder visible on the outside edge of the sprocket I was not sure if it was soldered on or if it had been shrunk on so I split the sprocket with a slitting disk in an angle grinder.Also not wanting to burn the paint off on the hub I just levered the sprocket off and split the solder. I have taken the opportunity to go up to a 1/2" x 5/16" chain and sprockets.The new sprocket  was turned to be a good knock on fit and locktite 638 high strength retainer used. Jobs a good un . Ken