I am putting together a set of parts to rebuild a Norton 16h magneto and have a query regarding the identification of the correct contact breaker cam.
Basically I have various cams but need to sort out the right one. So, if anyone can provide a photo of the correct cam that would be ideal.
Other than that I need to know where the contact breakers operate when the mag is set at fully advanced. On an M20 for example, the contact breakers open at approx. the 11 O'clock position when looking at the points end.
Also,on the cam there are various slots around the periphery. There is the long slot that operates against a fixed pin and limits movement of the cam during adv/rtd, there is the slot the adv/rtd cable attachment picks up on (and that will be at about 8 O'clock on the Norton type) and there are two other slots which have no particular function in some applications.
It is the position of these on the Norton cam that I need to know...Any photos/ info. much appreciated..Ian

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

Ian, as you probably know the 16H mag is driven the opposite way to an M20 (anticlockwise from the clutch side) It is tight wire advance, so the cable is at the front.
This is mine with the points just open. Bit awkward as some idiot has hung a chair in the way. Hope it helps.

Ron

email (option): ronpier@talk21.com

Thanks Ron..can you tell me approximately what position (of the clock) the contact breakers are in just as they are breaking on fully advanced?.I can't quite make that out....Ian

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

It's difficult to get straight on, because of the sidecar. But I have taken a shot from a bit lower down which looks straight to me. I'd say, between 2 and 3 o'clock. I put a 1.5thou feeler between the points and it fell out at that point, so not spot on accurate, but hopefully good enough for your purposes. Ron

PS. I just went down and checked it again a bit more accurately. My lever was just off full advance before. I'd say 2ish.

email (option): ronpier@talk21.com

I have face cams marked with "L" and "R" and shouldn't you have an "R" for a Norton 16H?

Henk

email (option): ahum@quicknet.nl

My blue Rizla pulls out at about 2 O'clock as well.

Thanks chaps..I know there are 'L' and 'R' marked cams and I thought 'R' was for a Norton.. but I also have some with no marks ..and I have one marked 'L' where the points open at 2 o'clock..then there are the thick and thin ones..confusing or what?.. .I'm not sure if I have an 'R' marked cam, more searching through boxes is required....Ian

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

R's are for NoRRTon.
Thick ones and thin ones: look at the end plate and fit the right one.

And you can replace the end plate to have a non stressed cable on full advance, so if that breaks, the engine wont be damaged. (Non original, but I like it)

Hi Rob...I'm doing the mag for Rik so I don't think he will be very enthusiastic about me changing the points end casting...He would have to sell his 'rivet counters' T shirt.. ...and I don't want my house petrol bombed.....Ian

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

He did not notice it in 2009, whilst seeing several early features on my engine.
But I get your point
If you need more pictures, I maygo down and do something with digital thingies, but dont mention it to anyone!

Hi Ian,

If you can't find one I can have a look, I probably have one. I don't need it myself anyway, no Nortons in my shed. Next to that I would love to sell Rik such a rare expensive Norton part.

Henk

email (option): ahum@quicknet.nl

Hi Henk..If you have one bring it to Stafford and I'll force myself to buy a Norton part... ...Ian

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

Would this one do Ian? I have 3 of them this is the nicest R face cam, I have no thick R face cams just thin in the R version.

Henk

email (option): ahum@quicknet.nl

Hi Rik..and Henk..I've now sourced a correct 'R' cam but bring that one along to Stafford Henk and I'll fit the best one of the two.... The only anomaly now is that the arrow on the best of my drive end covers is showing anti clockwise rotation and I don't have a clockwise one good enough to use.
If anyone has an undamaged and uncorroded one of those I'm in the market for one...
Everything else is now correct...Ian

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

Hi,

I've just been fettling my recently rebuilt WD16H. It doesn't start or run too well but I've not been out on the road yet, so it's hard to tell whether I have a big problem or not. I'm not convinced that the carburation is right but that's another story. Anyway...

The picture of Ron's magneto shows the advance/retard coming off the front of the magneto, which gives a 'tight' wire advance. My own magneto has the advance/retard coming from the back of the magneto. Also, the cam-plate has an 'L' on mine. Logic says that it is a 'slack' wire advance and I've timed the bike up in accordance with this assumption.

Were WD16H Norton's ever fitted with magnetos like mine; advance/retard mechanism at the back and 'slack' wire advance? Can anybody see any fundamental problems with running the magneto I have?

Regards,

Ian

A magneto needs the strongest magnetic field right at the moment it produces a spark. My guess it that a Norton with an L face cam in the magneto has to create a spark when the magnetic field isn't at it's strongest point ending up with a weak spark.

Henk.

email (option): ahum@quicknet.nl

The Norton 16H mag does run the opposite way to an M20
Anti clockwise looking at the contact breaker. They were indeed tight wire advance (cable at the front). But a slack wire advance will make no difference.
In fact, apart from originality, slack wire is better. If the cable brakes.....you can still ride home without the need to somehow wedge the cam at full advance. Ron

email (option): ronpier@talk21.com