1955 ES2 rebuilt magneto, no spark

Previously paul_gooch wrote:

Luckily, my 1955 ES2 started 2nd kick after an extensive rebuild.

After several start up procedures on the driveway, it stopped after around 500 yards on it's first test ride.

I found no spark at the spark plug, changed the plug and got a nice big spark again. But it still wouldn't start, not even a misfire. I checked and no spark at the spark-plug again. I have checked with further sparkplugs, and checked the points and timing, all haven't moved or appear to be operating as they should.

I don't really want the hassle of removing the mag, especially as I paid around £200 for a rebuild, and it was working fine and I cannot think of anything that would cause the complete failure of a rebuilt Mag in this way, after just a few start ups, which would require a strip down after such short use.

Has anyone got a test preocedure for the mag in situ? Many thanks

Paul

what about the HT lead is it broken in side giving you a intermittent spark , yours Anna J

Paul, if you paid £200 for a rebuild and reconditioning then why should you consider stripping and rebuilding it? Take it back to the guy who charged all that money and get him to sort it out.

There are a few checks that you can do before removal. Are you seeing any spark across the contact points at all or is it completely inert ?

It's a bit of a fiddle on Nortons where the pick-up is next to the cylinder, but if you can remove the pick-up, together with brush and spring, you can make sure that they're not damaged and that the slip ring is clean. I take it that no great quantities of oil or fuel have poured over the mag ?

I hesitate to suggest that you stick your finger in the opening and give the armature a good spin....but if there is a cat close by being careless with the tip of its tail....

I'd certainly check that the HT cable is correctly mounted at the pick -up and check for a spark from a bared cable end...no plug or cap to complicate matters.

Beyond this, I'd remove the chain from the drive pinion and check that you can feel resistance to turning as it approaches maximum flux which occurs twice on each revolution. It should feel as if it wants to rock backwards or forwards at this point.

Previously richard_payne wrote:

There are a few checks that you can do before removal. Are you seeing any spark across the contact points at all or is it completely inert ?

It's a bit of a fiddle on Nortons where the pick-up is next to the cylinder, but if you can remove the pick-up, together with brush and spring, you can make sure that they're not damaged and that the slip ring is clean. I take it that no great quantities of oil or fuel have poured over the mag ?

I hesitate to suggest that you stick your finger in the opening and give the armature a good spin....but if there is a cat close by being careless with the tip of its tail....

I'd certainly check that the HT cable is correctly mounted at the pick -up and check for a spark from a bared cable end...no plug or cap to complicate matters.

Beyond this, I'd remove the chain from the drive pinion and check that you can feel resistance to turning as it approaches maximum flux which occurs twice on each revolution. It should feel as if it wants to rock backwards or forwards at this point.

Cats you cannot do this to cats its cruel and you will not do this to my pussie !!!

Hi Paul,

I rebuild a lot of Lucas mags here in the USA & have seen this before & for different reasons. I am sure that if your mag rebuilder is a fair guy, he will want to check out the mag himself as it would be part of his warranty & reputation, so give him a ring first.

Be certain that when you move the advance lever on the handlebars, that the face cam in the mag is moving, I have seen the plunger get dislocated & force the cam at full advance (not good for starting). Are you moving the spark advance to full retard when starting? At low speeds, you will get a much better spark at full retart, then full advance (plus less leg injury).

Was the armature rewound? A rewind alone costs around 120 GBP. On a newly rewound armaute, on a rare occasion, you can get a failure. It is rare, but can happen with the very best rewinders. this can me partially tested on the bike: I would reccomend having a look at the "complete high tension continuity", "internal HT continuity", and "low-tension continuity" sections of the Brightspark Magnetos website on this tab:

http://www.brightsparkmagnetos.com/DIY/index.htm

You will find a wealth of free troubleshooting information there.

It is good to check a few simple things first. I have had many of the oriental pick-ups sold by the major suppliers in the UK fail. They will leak spark to earth. You can see it in the dark. Bas connections where the plug wire meets the boot is sometimes the cause. If you can, replace the pick-up with an old one & test, remove the spark plug boot & be sure the connection on the cap was centered in the wire. Be certain that the cap is non-resistor & be certain that the wire is copper. As was mentioned earlier by Richard, check the slip ring, if it is covered with oil, or a track of black carbon, there is your problem. There are a lot of oriental & indian brushes on the market that are too hard, or too soft. Too soft will coat the slip ring. It can be cleaned in place if care is taken. I prefer a siamese cat tail myself, with a bit of solvent on the tip . But seriously, a q-tip with solvent will work, or a rag, over a pencil on the eraser end also works well.

Points end: check the points gap for .012 at its greatest opening (.018 for the spark plug).Then grab the points arm & tug on it straigt out, then push straight in. There should be less than .001 of an inch of end play. If you dont have a dial indicator for this, you can check the points gap in full in, and full out.subreact the difference. If there is too much end play, there will be too much variation in the points gap.

In the end, I would strongly suggest calling the rebuilder first to get his thoughts before putting too much time in. If you get stuck, feel free to email me directly, anytime.

Skip

IHello Paul

I have just started my triton T 110 engine for the first time since 1980 and got no spark I then looked at the magneto and cleaned the slip ring after taking out the brushes and put my little finger soaked with a bit of rag with petrol and got a gentle shock after turning over the kick start by hand with the spark plugs out . Should have put a pencil and rag soaked in petrol to avoid the shock.

Put the brushes back and plugs and she fired up on the 3rd kick

Very surprised that I got a spark after so long

John

One last thing - give the points a gentle clean. It's not uncommon for the points to have an oxide film or even a particle of non-conducting something lurking after a rebuild or something get in during the first run. Worth a check.