Atlas timing chain

Just the same as the earlier twins. Will need to dig out the book for other info though.

ignition chain was the same on all Norton twins that used an ignition chain.

size: .375 x .250 x .155 with 42 links

When I last changed my camshaft chain it was too tight to fit even without the tensioner in place. I've since found out I should have washed the packing lube out with petrol and re-oiled it. I wasn't that the chain was really too short - it's just that the manufacturer's grease was clogging all the gaps. It was bar tight and I didn't want to risk the camshaft bearings etc. Never seen this mentioned in a manual...

I suppose that means a new ignition chain will start off properly adjusted but become far too loose as soon as it all warms up.

Hi David,

I've never seen a timing chain covered in grease. I would suggest it maybe wasn't intended for a Norton timing chain but maybe some lawnmower application. Not worth messing about with inferior bits in this department IMHO.

Don't forget the magneto and cam chains are not the same! The magneto or timing chain is narrower than the cam chain. I am sure you are fully aware of that anyway. Odd having a chain covered in hard grease though. Haven't come across that before.

Bit of a mystery...wasn't 'hard'. Just went to the shed to check. The chain is oily with original lube not really grease... 38 pitches .375" x .225" .. .I marked the box "cam chain too short unused 2008". Just looked at my books, my manuals don't say but Bacon's "Norton Twins" says as does Eugene - mag chain 3/8" x .155 (and cam chain 3/8" x .225.) (So I still don't know why my chain too short? It's Renold - bought from reputable Norton specialist. Sorry - breaking into the original thread.)

Previously david_evans wrote:

Hi David,

I've never seen a timing chain covered in grease. I would suggest it maybe wasn't intended for a Norton timing chain but maybe some lawnmower application. Not worth messing about with inferior bits in this department IMHO.

As it happens when I were a lad I needed a new primary chain for a Villiers 3T I was told and bought and fitted the same pitch as a Norton timing chain. It fitted but wore out in no time. So yes it is a common size but some are made of lesser metal than others.

AL Oz

In the good old days I used to boil my Commando rear chains in linklyfe. You always had to move the rear wheel forward to get it to fit then 50 miles later it had squidged the grease out and needed adjusting again. My right boot had a blob of black grease that used to tread through the house ( my Mum was well impressed) and the rear number plate and under the seat was always covered in the stuff. How I never set the garage on fire with a can of grease balanced on a camping stove is a miracle. I graduated onto an old deep fat frier in the end and now have a 520 o ring chain. Gone a bit off thread here