These have been a pet peeve of mine since I got my first Vincent twin on the road almost 40 years ago, OH Damn, Really???, anyway I found that I could never get more than a few 1000 miles from a rear sprocket, and some of the engine sprockets didn't fare too well either. After trying several suppliers I started down my own path.
First was to source ring sprockets for the engine sprocket. I took a decent used hub, machined off the worn teeth and shrunk and tack welded the ring sprockets to the old hub. The rings were made in SAE 8620 and case hardened. They take a bit of work and do cost a bit more than what is available new, but have worked well.. I have probably made 60 or 70 or so of these.
Next was the rear wheel sprocket, these I seemed to wear out at an alarming rate, some only last a few thousand miles, and when I was using the bike more than in the last few years was just a pain in the backside. Some years ago I had a local sprocket maker make me about a dozen sprockets, again in 8620 and case hardened. They did warp a bit from the heat treating but a few minutes on the press and they came out quite true. Those back in the day cost close to 2X what was available but well worth it to me as they lasted very well indeed. When I tried to order some more the price had almost quadrupled!
After trying several other options I finally gave a big sigh and gave up..... then talking to a local guru, we talked about using SAE 4340 (or equivalent) and nitriding them in a salt bath. So I took a big breath and made a batch.
This past year I finished a new project bike and it has these rears sprocket on. I rode it to the International rally in California and back. I had cause to remove the rear wheel (to redo a very poor black centre/red stripe paint job) and had a good look at the state of the sprocket. Below is a picture of the teeth, with 4500 miles on them, note this is a 520 chain, so a somewhat higher load on the teeth than a wider 530 chain.
I am pretty pleased with the result, as you can see the sprocket diameter is spot on with the rollers just touching the base of the tooth profile and showing good contact on the teeth overall.
This is just a long winded explanation of one of the small issues when re doing a bike that is going to be used as intended,..,
Cheers
and Happy new Year
First was to source ring sprockets for the engine sprocket. I took a decent used hub, machined off the worn teeth and shrunk and tack welded the ring sprockets to the old hub. The rings were made in SAE 8620 and case hardened. They take a bit of work and do cost a bit more than what is available new, but have worked well.. I have probably made 60 or 70 or so of these.
Next was the rear wheel sprocket, these I seemed to wear out at an alarming rate, some only last a few thousand miles, and when I was using the bike more than in the last few years was just a pain in the backside. Some years ago I had a local sprocket maker make me about a dozen sprockets, again in 8620 and case hardened. They did warp a bit from the heat treating but a few minutes on the press and they came out quite true. Those back in the day cost close to 2X what was available but well worth it to me as they lasted very well indeed. When I tried to order some more the price had almost quadrupled!
After trying several other options I finally gave a big sigh and gave up..... then talking to a local guru, we talked about using SAE 4340 (or equivalent) and nitriding them in a salt bath. So I took a big breath and made a batch.
This past year I finished a new project bike and it has these rears sprocket on. I rode it to the International rally in California and back. I had cause to remove the rear wheel (to redo a very poor black centre/red stripe paint job) and had a good look at the state of the sprocket. Below is a picture of the teeth, with 4500 miles on them, note this is a 520 chain, so a somewhat higher load on the teeth than a wider 530 chain.
I am pretty pleased with the result, as you can see the sprocket diameter is spot on with the rollers just touching the base of the tooth profile and showing good contact on the teeth overall.
This is just a long winded explanation of one of the small issues when re doing a bike that is going to be used as intended,..,
Cheers
and Happy new Year