Ummmmmmmm....... I'm not sure who you talked to but ALL the gear box sprockets are the same. Compare the pic you just posted to the pic they have posted on the link I posted previously. They're identical. You will want to order either a 21 tooth or a 22 tooth as the 16" Chief wheel make the gearing extra short.Scottie
I asked a shop with high tech equipment for an estimate to make one and they said $350. Each additional one was like $40.
Scottie J, you might consider a change to an H type gearbox if you are using a narrower tire/combo like the Constellation and Interceptor used. It may not be quite as strong as the AM series gearbox but they were strong enough and can be converted back to the pushrod clutch of the later Interceptor models. The ball ramp clutch was not the best idea that Royal Enfield came up with. The H series are much easier to get parts for.
I would be keen to buy a rear sprocket too. If a group build goes ahead would whoever organises it be able send one to Australia, I pay all costs of course.Regards Charles
When looking for a gear maker...use the search terms "gear hobber", or Gear cutter. Not a lot of CNC shops can properly cut gears and then know enough about having them heat treated properly.Gunner, machinist and machine tool repair