Chain-illiterate; best chain for my '51 ES2 ??

O ring chains are wider than normal chains so you do have to check your clearances. I would just stick to a reputable 1/4" x 5/8" (a 520 being the new-fangled equivalent). Being a boring stick-in-the-mud, I use Renolds chains and lubricate them with semi-fluid grease. Having your engine breather pointed at the gearbox sprocket is a very good idea but remember it only breathes oil vapour onto the chain when your bike is good and hot. If you are doing frequent 200+ miles trips your chain will be perfectly lubricated that way.

The days of taking the chain off and boiling it in Lynklife are long over for me.

In the old days when a chain cost 13 guineas, 14 florins and 27d people used to look after their chains better as they cost more than the average terraced house in Emmerdale street.

If your bike is an all weather bike and is used daily in driving rain and standing water, probably an o ring chain would be good, however, they suck a considerable amount of power which may be noticed on a low power machine.

A good quality maintained non o ring chain is perfectly adequate for the application.

Fitting a new chain on buggered sprockets, or the other way around, will shorten the life of the new components dramatically as they try to bed into the old bits, it's unlikely the old worn out components will be restored by the addition of fresh new bedfellows, although i know i would be restored by the addition of a brand new 24 year old russian sweetheart in my bed.

A 24 year old Russian would be more dangerous than worn out transmission,quite likely to turn you in for scrap value. Because our sprockets are often combined with drums and box sprocket hard to access they cannot be viewed as "regular replacement" and so need regular maintenance instead. A good quality (chinese Reynold??) non O ring kept clean and well lubed with "period style" lubricants will last well. Engine breather, drip feed, graphite bath, brushed on EP 140/90 ,sprayed on old style foamy grease (not wax which won't get in enough) . All messy time consuming stuff,An "o" ring chain can work(but don't usually fit the space) but you still need to clean/ lube regularly to protect those expensive sprockets. (which may not be still made) .Orriginal Norton sprockets were made of very good stuff, 35k later my 1960 99 sprockets still look new.Been through a few "pattern " rear sprockets on the Atlas which needed work to fit. Try "Andy chain man"

You want to preserve your sprockets, the chain is a consumable so 2 potential strategies.

1. Buy cheap chain, ignore it cleaning wise but change it often before it wears enough to damage the sprockets.

2. Go to Andy the Chainman and get his Iwis chain and look after it.

Not really what you wanted to hear!!, The alternative is to ride a cheap modern with easily replaceable "putty" sprockets which are designed to last the same time as the chain.

Starting with new sprocket's and chain:- keep them clean and lubricated. Back in the 70's when I did 100 miles a day on a Trident I had two chains which I changed around each week end. These were cleaned in paraffin and lubricated . One on one off, I used a split link attached clean chain to the dirty and pulled the clean one into place. I then had a week to soak the dirty and re-lubricate ready for the next week.

On modern bikes with "o" ring chains I used spray chain lube to wash the grit off and lubricate the outside so it would not rust. This method gives good chain and sprocket life and ease of maintenance. Cost is a greasy rear wheel, nothing a wipe with a cloth will not cure.

If you keep on top of cleaning and maintenance it is easier than If you let it get a major job.

I've not been impressed with the quality of the chain that Renolds sell for motorcycles these days.

There is very little space between gearbox and rear chaincase on the Norton and modern metric-equivalent chains often have thicker side plates which reduce this further.

There is no great advantage in having thicker side plates. It increases weight and a decent old-fashioned 5/8" x 1/4" chain is plenty strong enough.

The best commonly available imperial standard chain seems to be Regina.

There are two well-known suppliers of 'classic' chain in the UK who do the shows and are helpful with advice. I use both happily.

Google 'The Chain Man' and 'Sprockets Unlimited'.

Yes,... you need 5/8"X 1/4" 520 motorcycle chain, mainly due to limited space alongside the inner chain case and to the fact your sprockets are made for that width. As far as length goes, first make sure your primary is in good nick and is correctly adjusted (3/8"minimumup and down movement at the tightest spot) then buy a main chain several links longer than whatthe link count was on your old chain and custom fit it to your bike. Don'trely on your book as being correct.

Cheers,

Paul

If you find where Andy is going to the next bike show/jumble he will make you up a chain on the spot and give you a tutorial on how to shorten the chain ,he can also supply half links and spare spring link.

Most modern chain breakers are pretty much hopeless when you use them on non O ring chains. Try and pick up a proper Renolds breaker. They turn up on auction sites and at autojumbles.

Be sure to check the spec of chain you can buy in long lengths. Some industrial chain is low spec and you could end up replacing your chain rather frequently.

I generally get about 6,000 miles out of a rear chain.