Hello, being somewhat of a novice when it comes to mechanics I could do with some assistance please!
My cable sheathing jumped out of my magneto control lever on the handlebars. Pulling it tight to reposition it back in the hole of the lever, I have upset the running of the bike in someway? She coughs and backfires now and will only run at 40mph max, with the magneto lever about 30% on, otherwise she will not run at all! Before, this lever was only on for starting,then in the off position when riding.
Please can anyone advise me what the problem may be, or better still advise whether there is anyone near the Ross-On-Wye area who can come and have a look? Happy to pay! I have only just got the bike on the road this summer, so in the process of joining the Gloucestershire branch and waiting on a reply. Therefore I have not yet managed to find a good mechanic for such things nearby.
I'd appreciate any help you can offer me!
Thanks in advance.
Laurence
Do you have a manual? Ther…
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It will depend if your mag…
It will depend if your magneto is tight wire advance or slack wire advance to where the lever should be. WD16H are usually tight wire advance so you will need to pull the lever all the way back when running. But that doesn't mean yours is... my WD16H has been changed to slack wire advance.
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Thanks both for the reply,…
Thanks both for the reply, my 16H is a pre-war bike (1936) if that makes a difference?The cable is slack during normal running mode, i.e. the lever is as far to the front of the bike as possible. I only gave it a third of a pull towards the rear of the bike to start it. Once started I'd pull the other lever, (the air control), fully on, (towards the rear of the bike), then push the magneto lever off, (again to the front of the bike), and she purrs beautifully - or did so before I fiddled!I've removed the cap and can see the end of the cable with the nipple on which sits within a V slot on the circular plate behind the contact breaker. When I pull the magneto lever back and forth, I can see it rotating the shiny circular plate at the back, (forgive my lack of technical terminology).Therefore all looks as it should to me?LaurencePreviously David Cooper wrote:
Do you have a manual? There is a free download at wdnorton.nl.Sounds like the nipple at the magneto end might have come out of position. Take off the magneto end cover and have a look and see if the advance-retard is working properly. It is fairly obvious when you look at it.From your mail - which way do you usually set the level to start and to run? They are usually tight cable to advance - so it should run usually with the lever pulled back. Your mail hints the opposite. Which is a bit odd. Racing bikes are more likely to use slack wire on advance so if the cable breaks in a race it does not matter so much.
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In that case it sounds jus…
In that case it sounds just like what happened to mine the last time I took it for a long run. The timing had slipped, leaving it too far retarded. It started only after I had the nerve to pull (in my case) to full advance and then it was totally gutless.So I had to re-set the mag sprocket and tighten it up a bit harder this time. I don't want to overdo it in case it gets jammed on.Now it's OK again. I don't know how precise other people are; but all I know is that it is set a bit before 1/2" BTDC. I can always retard it a little on the lever.
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Laurence, the pre-1947 sid…
Laurence, the pre-1947 side- and overhead-valve Nortons are quite unusual in that due to the fact that the inlet camshaft (which turns the magneto) is in itself driven by the exhaust cam, the magneto turns clockwise (when viewed from the drive end).
The standard tight-wire advance therefore invloved the cable entering next to the cylinder. If yours enters on the side away from the cylinder (nearest to the battery) then it has been fitted with a slack-wire advance end cover. Some people do prefer this. It doesn't matter either way but it is vitally important that you're advancing the ignition for normal running.
The points plate (when viewed from that end) should be as far clockwise as it will go on full advance - whether by the cable lifting it on the left hand side or the spring pushing it downwards on the right hand side.
A photo would be handy...
To pick up on David's comment, I set mine 'as acurately as possible' at 7/16" BTDC. I can get it pretty much spot on after a couple of goes. I also find that the lever backed-off a fraction from the full advance position gives the best running.
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Hi Laurence, I find the si…
Hi Laurence, I find the simplest way to tell which way to move the ignition lever for advance/retard,is to watch which way that shiny disc (face cam)behind the magneto points rotates compared to points rotation when turning the motor over with the kick tarter . If, when moving the advance/retard lever,it rotates in the same direction as the points rotate, that is retarding the ignition. So, when it rotates the opposite way (against) thepoints rotation,it is advancing the timing.
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Okay, thanks to your help…
Okay, thanks to your help I now know I have a tight wire advance as the cable comes down nearest the cylinder. I have taken a photo however with 1mb max. upload size, I'm not sure how clear it will be?
The points plate appears to be right, as in when the magneto lever is slack, i.e. as far as it will go to the front of the bike, the small slot to the points plate where there is a small interference nipple touches this slot end, and when you pull the lever full extent to the back of the bike, the plate revolves until the fixed nipple makes contact with the opposite end of the slot? The slot is about 1/2" long to the edge of the contacts plate.
Previously richard_payne wrote:
Laurence, the pre-1947 side- and overhead-valve Nortons are quite unusual in that due to the fact that the inlet camshaft (which turns the magneto) is in itself driven by the exhaust cam, the magneto turns clockwise (when viewed from the drive end).
The standard tight-wire advance therefore invloved the cable entering next to the cylinder. If yours enters on the side away from the cylinder (nearest to the battery) then it has been fitted with a slack-wire advance end cover. Some people do prefer this. It doesn't matter either way but it is vitally important that you're advancing the ignition for normal running.
The points plate (when viewed from that end) should be as far clockwise as it will go on full advance - whether by the cable lifting it on the left hand side or the spring pushing it downwards on the right hand side.
A photo would be handy...
To pick up on David's comment, I set mine 'as acurately as possible' at 7/16" BTDC. I can get it pretty much spot on after a couple of goes. I also find that the lever backed-off a fraction from the full advance position gives the best running.
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Another photo attached. At…
Another photo attached.
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Do you have a manual? There is a free download at wdnorton.nl.Sounds like the nipple at the magneto end might have come out of position. Take off the magneto end cover and have a look and see if the advance-retard is working properly. It is fairly obvious when you look at it.From your mail - which way do you usually set the level to start and to run? They are usually tight cable to advance - so it should run usually with the lever pulled back. Your mail hints the opposite. Which is a bit odd. Racing bikes are more likely to use slack wire on advance so if the cable breaks in a race it does not matter so much.