Sprockets!

My original Atlas rear sprocket lasted 85,000 before I changed it.  The replacement was a cheapo off Fleebay and lasted less than 5,000 miles.  I then purchased a 'made in England' rear sprocket and rear chain off a well-known supplier. The chain was rattling after less than a 1000 miles and the sprocket began to sport spikey teeth.. Exploding the theory that if you purchase a branded item for extra dosh then you got quality.

I gave the chain a soaking in a 'Lynklife' tine of goo every 6 months and also sprayed it with chain oil every month as well. It made no difference to the longevity of either the chains or the sprocket. In the end I went for a German brand of rear chain and discovered that this was the solution.

Yeah, of course chains and sprockets are consumables - on every bike.

A worn chain will wear sprockets faster. Use a decent chain, DID or similar, and replace when you measure 1/16" elongation over 12" (Imperial sizes 'cos that's how chains are made). Or get a BMW...

Is BMW off topic on here Stan? Or have you been shafted?

Seriously, I have always stuck with original equipment, inc chains, although I must confess to using some German chain oil. (You won't need that on a B*W)

Incidentally, I have only ever had one Norton chain failure and that was on my 16H when the primary split link came apart. I put a new chain on my Commando @ 26,000 miles, replacing the original (Like for like) but the original sprockets to this day show very little wear.

Chain only replaced because it had reached the end of its adjustment and not one for removing a link from an old worn chain.....

Maybe good adjustment, alignment, lubrication  and riding style play a big part but my rule, like my Father before me is: Once new, always new !

... gearbox sprockets as "service items" on British bikes where the sprocket is behind the primary chaincase. I'd only be replacing them in a major overhaul. This is different to most Japanese machines where the front sprocket is more accessible because of the crossover design, but have no idea why they might wear more quickly.

Out of sight is out of mind eh?

Whenever I pulled the chaincase off a second-hand Commando I'd bought, the gearbox sprocket has been knackered; although I've not had occasion to do that for some years now. Commando might wear slower than a Honda 'cos there are more teeth, 21 versus 14, but wear they do. I'd say it stands inspection whenever you replace the chain, particularly if you let the chain go until it runs out of adjustment.

Yes Neil, I count an '81 BMW R100RS among my collection (accumulation?). To go a little further off topic, getting shafted is not a panacea but simpy pushes the problem down the road a few years. After 90k miles say (YMMV), you're looking at rebuilding the driveshaft UJ and replacing the splines in the rear wheel - makes chains and sprockets look cheap.

I think it’s accepted that orriginal sprockets were made of very hard steel or perhaps very well tempered and owners that followed the lubrication routine with graphited grease and EP90  got a reasonable life from chains , sprockets hardly wearing at all , my 1960 sprockets having done 50000 miles are still looking good  for another 25000 ?. I don’t know if AMC stuff is as good as Bracebridge st . What I do know is that chain WAX for O ring chains is not any good for lubricating non O ring chains , these still need proper grease or oil . Even better an automatic chain oiler . The last 3 bikes I looked at for other owners all had rock tight chains when under rider’s weight.

... about chain wax and O or X ring chains - however my experience of these is limited to 20,000 miles on a Hinckley Triumph Tiger 955i. I only used Wurth chain wax in all weathers and the chain required only one adjustment in that mileage and was still well within wear limits when I sold the bike with 25,000 on the clock.

O ring chains should only need minimal lubrication anyway as the wearing parts (bushes, pins & rollers) are tucked away behind he seals.

Alec Stevens  " I know the gearbox sprocket is hardened"

Did you personally bother to do a hardness test? 

Robert Tuck " I think it’s accepted that orriginal sprockets were made of very hard steel "

My hardness tests proved that sufficiently hard sprockets were not consistent. 

Over the years, prior to 2000,  I built a stock of sprockets from 18T(RGM) through 24T and many other vendors

After the 2017 INOA rally, a discussion on worn out, but fairly new,  sprocket popped up on a forum. A Canadian barely made it home from the rally, He had to tighten the chain on an almost toothless sprocket to finish the ride home.

A sprocket test series was done on many sprockets also trying to discover the source.  The results showed genuine old norton sprockets were indeed hard. Many "new", recent mfg, were not even close  to original hardness. Some soft sprockets were returned unused to the vender and they were notified. Many were stamped "Made in England". It was replaced with one new aftermarket Taiwan mfg was very hard, though the gearbox spline fit was marginal and needed fettling.

So here we are 6 years later and still in the discovery phase of the old defective sprocket issue...the discussion might still exist on access norton forum

Added:

IIRC, it was offered the "Made in England" were of Vellocet mfg

Current status is unknown

Hi Ian, if you read my post again I think you will find we are NOT at cross purposes. Wax is ok with O ring Chain , but will not get into non O ring chain which needs a graphited grease plus a regular dose of oil . When talking of orriginal Norton parts I am referring to parts fitted by Bracebridge st to bikes before 1963 , after that AMC  took over Norton assembly and made many changes to parts and finishes at Woolwich where they had little respect for what was done before . 

... I did misread what you said. Apologies.

For the limited usage my older bikes now get I find a decent aerosol (I use Silkolene) applied regularly does the job on the standard type chains.