I'm confused now, having talked to an old dispatch rider whilst at a show today. He said that I was running my M20 retarded. Ive read several posts saying that if the cable enters the Mag from the Right Hand side as you look at it then fully advanced is cable tight lever pulled towards you. He has told me the opposite. Can anyone confirm for me please. My Mag has the cable entring from the right viewed from the points cover side.

email (option): dwhitehouse1@sky.com

Hi Dave...Cable entry on the right is 'tight' advance on an M20 of the wartime period...

Post war it was swapped around so that it was fully advanced with the cable 'slack' and then cable entry was on the left of the contact breaker housing....

It's only conjecture but if your DR was riding M20s in the post war 'National Service' period I suppose it is possible that an Army M20 fitted with a replacement mag might have had the later set up...

This would have been an alteration to a wartime bike though...No new military M20s were built post war...

Other wartime parts were replaced with slightly different, but current, parts.

For example the rear frame section with twin sidecar mounts (none on a solo contract WD bike and only one on WD sidecar contracts)and the MU42 headlight, which was a replacement part for the DU42...

I wouldn't mind betting the MCR1 regulator and the early dynamo might have been replaced as well when they became obsolete...Ian

email (option): ian@wright52.plus.com

OTOH if he was riding an M20 in service then he is not exactly young so the mind might not be qute as sharp as it was back then.
Add to that there was a very good chance he owned a bike or two post WW II all of which were most likely slack for advance.
When I was riding the WD B40 as a daily ride in the trim that I bought it from the army it was not uncommon for a digger to stop me in the street & tell me he rode one of these BSA's in "the War".
Only once did I bother to point out that this bike was built 22 years after the War ended as the stories & glint in the eyes of the old blokes was much more important than fact.

email (option): wariron@tpg,com,au

Good point Trevor..I've met some blokes who's memory was very 'sharp'..
One ex Reme fitter came up to me and immediately started a detailed discussion about various technical aspects of the M20...My guess is he was at least 75 years old at the time...

The memory does play tricks however...I've been told of 750cc A10s, a BSA 'Tiger 650' etc. etc....Like you, I don't usually interrupt the flow of memories by correcting such details...

It is said the only reality is the present...I'm beginning to believe that myself as I get older... ...Ian

email (option): ian@wright52.plus.com

Thanks Ian,

I thought I had read it right. All I need to do now is to stop the lever moving to the retarded position during normal running!! I keep tightening the nut in the centre, but it goes loose after a few goes.

email (option): dwhitehouse1@sky.com

Hi Dave,

It doesn't normally get loosen by itself.
Either you miss a shim in the lever mechanism,
And that makes the lever inside faces touch the top dome,
So after every time you retard (For low rev idle, or starting, for example)
You have kind of a ratchet effect which loosen the lock screw,
Or, if it is just the thread that's too loos, you can try tightening
The top center screw after applying some "locktight" on the thread,
Or some nail polish, which also does a great job.


Noam.

email (option): noam10@gmail.com

Many thanks, I'll give that a try.

email (option): dwhitehouse1@sky.com

There are at least three different friction systems in British top levers of this period. It's worth checking which make you have. Later war levers appeared on the proprietary spares lists which might imply that they could come from various manufacturers.

The most reliable (and complex) is the Doherty patent system supplied primarily to Norton (naturally !) This uses a friction washer retained by a locknut secured by a 'D' shaped washer under the conventional cap and hex. nut.

Amal used a similar friction method but without the locking system so if the top cap comes loose, everything does.

The crudest but actually quite reliable is the Bowden (as used by Matchless) which relies on a leather washer in a conical seat.

As mentioned, they shouldn't come loose and can be as tight as you'd like them to be.

Thanks Rik,
I'll go and have a look now.

email (option): dwhitehouse1@sky.com

OK, this clears things up for me too. I have cable entry on 6 mags on the right.

So, "cable right, cable tight" seems to be the maxim. Yes?

email (option): britool51@hotmail.com

On an M20 (with anti-clock mag), yes. Norton have tight wire advance on the left....but you're unlikely to mix them up as HT pickup is on the cylinder side.

Also there are no studs in the bottom of the Norton mag to locate it on the crankcase (as on an M20). For Norton applications the mag is bolted to a separate mounting platform...Ian

email (option): ian@wright52.plus.com