Britbike forum Forums British Motorcycle specific Brands Norton bulletin board model 20 magneto timing

Hi,

first post in the Norton section. I've got my mates model 20 twin port in my shed minus its mag/dyno.

before i get stuck in, i'd like some advice on timing the magneto to the motor. (magneto to the front of motor)

much appreciated,

Richard.

Its going to be something like this ? - but with exhausts !
https://cybermotorcycle.com/gallery/norton-1930/images/Norton-1930-Model-20-HnH-1.jpg

WC Haycraft "The Book of the Norton" 1936 sez that the ignition timing is 5/8" btdc (fully advanced)( 42 degrees),
(1932 and later, doesn't specify earlier engines) and shows using a degree wheel on the crankshaft nut.
Its not that difficult to get the alloy cover off the primary chain ?

Yell if more needed -, you know about cigarette papers and pencils down plugholes ?
Cheers.

My 1952 ES2 (later I know) runs very nicely on 5/8" fully advanced.

thanks guys.

with reference to fully advanced, is this set with the advance lever fully open, and buy closing it one would retard the ignition.

also, before connecting the the chain do you set the points to just opening with the advance lever fully open and the piston 5/8" btdc.

Not had any experience with advance/retard levers.

cheers

Richard.

"Its going to be something like this ? - but with exhausts !"

its going to be exactly like this, that's the bike!!

small world

Richard.

That is exactly the gist of it.

Couple of comments, which may assist further.
ALWAYS rotate the engine FORWARDS while setting the timing (and the magneto 'backwards', since that is how it operates).
This prevents all your backlashes accumulating.

The success of this depends on the quality of the fit of the sprockets to their tapers (if they don't have keyways), so checking the taper fits has some bearing on reliabiliity.
Tapers can sometimes be ground to a better fit using valve grinding paste, if needed.
And when finally fitting them up, a LIGHT tap with a hammer can ensure a good strong fit to theiir tapers.

CDouble check also that your advance/retard lever works as you suggest, it is possible to have them work the opposite way.

And ALWAYS check that the spark is where you expect it to be when all is done, it is sometimes possible for something to jump out of position in the process,
which can make life miserable until you figure this out...

hopethishelps.

Google is getting spooky. !?
Lovely bike.
Hope to hear how you and your mate get on with it.
Cheers.

Some Nortons had "tight wire advance", others "slack wire". The only way to be sure is to pop the cap off the mag end and look at which way the cable pulls the cam plate. Then check which way the mag spindle rotates when the engine is running. If the cam plate goes in the opposite direction to the spindle when the wire is tight it's tight wire. Obviously if slack, then....

Slack wire advance is slightly preferable as with tight wire the tension on the cable can gradually retard it as you ride along. Then you wonder why the exhaust sounds flat and all the power has vanished......

cheers chaps.

cut a long story short, it was one of his uncles collection who died around 10 years ago. in the mean time his cousin who's a bit of a tosser needed some money so raided the garage for some scrap metal to take to scrap man. hence no exhausts and countless other irreplaceable spares from other bikes went missing. my mate boarded the garage up for his auntie to prevent anything else going missing.

When his aunt died he expressed an interest in wanting the Norton, but the tosser wouldn't sell him it, so he had to bid for it at auction.

only thing missing were exhausts, which we have new ones. wiring needs sorting, which isn't hard and needs a good service.


on nights now till Christmas, so progress is now somewhat slow. will keep posted


regards

Richard.

managed to get the thing fired up over Christmas. first time in 50 years


https://www.youtube.com/watch?v=JqwntYPDN_8



cheers

richard.

Thats just marvellous ! Congratulations.
Thanks for getting back to us too, so often these things just disappear into the ether, as it were.

Don't worry, they'll be plenty more questions in the coming weeks. 😁

Cheers

Richard.