final drive chain

Hey all,
I know this is a newbie question but I am getting conflicting searches online. What size final drive chain does my all stock 75 commando mk3 take? Thanks in advance.
Scott

The standard chain size is: 5/8" x 3/8", or: "530" although a 530 chain is slightly wider overall than the Renold 10B-1 original, however, a standard non-O-ring 530 chain shouldn't cause any fouling problems on a MkIII.

Thanks for the clarification!

99 link for 19 & 20 T sprocket and 100 links for couple T more and so on. So far every report of 530 O-solete or X-cellent sealed chaings that did foul AMC gear box chewed a clear silent path w/o harming the shell integrity but where can not see the groove. Andy the Chain man and Chain quality chooses might be searched up here or google for educational entertainment. Compare old chain vs new chain lift out of drum sprocket valleys to see where chain is riding at speed to judge time to renew.

The original chain would have been Reynolds 10b chain. [ I always bought that for my bikes and would get 6,000 miles out if it before it was u.s. and had to adjust it every 1,000 miles or so ] . 530 is wider and thicker and heavier and you might get 5,000 miles out of it. . Buy your chain from Andy Chain [ or me if you are in NZ ]. He sells IWIS 10b chain which will outlast any 530 chain. As it is thinner section, it is lighter as well.

Dereck

A DID brand 530 X Ring chain will fit a MK111. No half links are available though so it will not fit with a 21 gearbox sprocket to get the correct amount of adjustment. I have a 22.

johno

Gosh...5-6 thousand miles from a rear chain??!! There are rotary Nortons running around with 70,000 miles and more still on their original Renold GP rear chain and sprockets....so a friend who serviced them at Rotary Norton told me a few years ago. Oh gosh I forgot...the rotary lumps employed the rear chain within a proper oil bath chain case didnt they and such things do not give the sporty race bike look do they so were not included on many British motor cycles......!!
The MINIMUM chain life of a Renold chain is given IN THE MANUALS as 15,000 hours IF, and I repeat IF, employed as per the design manual..... 15,000 hours at 40mph = 600,000 miles.......which is a pretty good indication of just how incorrectly we employ our chains, compared to the design manual that is.
I guess that is why Renold recommended a rear chain running exposed to everything except correct lubrication should be removed every 1000 miles, washed in paraffin, dried off, dumped in a can of hot liquid chain lube grease, wiggled about for a bit and hung up to drain before refitting. In bad weather conditions the recommendation was to do it at a lower mileage. Wonder how many miles use one would get if one were to look after the rear chain CORRECTLY?? Mind you how long would they last if tensioned correctly.....and here I am remembering the reply a Gentleman gave me in answer to the question 'What effect on belt life does incorrect belt tension have' and his reply was something like as follows....' Ah we did testing on this subject years ago...i can probably find the results for you in deep hold stares if you want but basically a correctly tensioned belt will have a life 3 to 4 times greater than that of an incorrectly tensioned belt'. I assume the same applies to chain??
Personally in my day we had two rear chains and to change to the new relubed one simply undid the split link attached the new chain to the old chain and pulled it on which was not as messy or annoying as trying to get a chain to go around the gearbox sprocket. NOT that the chain was ever changed every 1000 miles. If my memory is correct in those days a new MADE IN ENGLAND 5/8 x 1/4 rear chain for a Norton Dommy cost about £2 - 17 shillings and 6 pence!!! When my Plumstead plonker crank would go into AMC in the morning and come out in the afternoon with a new FREE big end fitted.....no point in having friends working there if one didnt use them!!

I forgot to say . When I had my Suzuki 500 and Norton 750 Commando [ both at the same time ], I ran 2 chains for each bike. I used to swap them round and heat them in a grease oil mix. I found later that by just running 1 chain for 6,000 miles, was just as effective. In other words, I was wasting my time running to chains.
I still only run 1 chain now until it is stuffed, but I do lube it regularly.
Currently I am using Chain Bar oil.

Dereck