No sparks

[Worty]

Went for a 70m run today, bike ran well until the last bit.  Wanted to know if the ATD and timing was good, so opened her up a bit on a long incline near where I live.  Started pinging a bit, and engine would fade at around 60mph.  On the last run, it spat and popped ('oh siht', was going through my head).  Pulled over - bike running on one pot.  Very gently nursed her back home and found that an HT lead had come away from the maggie.  Great, I thought, simple fix. 

Unfortunately, when I came to check for sparks again, it was completely dead both sides (apart from a very occasional spark -although nothing now).  It must be a coincidence that the HT lead came off, as it appears I have a maggie/electrical issue somewhere.  It doesn't appear to be the ATD as the maggie amature turns fine, points are also fine.  Could this be a case of condenser failure??

[CheeserBeezer]

If this is the same magneto you bought from me, just send it back and I'll fix it - no charge. Andrew with apologies.

[RDfella]

No spark? Probably needs a new flint ....

[Worty]

If this is the same magneto you bought from me, just send it back and I'll fix it - no charge. Andrew with apologies.

Many thanks Andrew.  As per the PM, will do as you suggest!

[Worty]

No spark? Probably needs a new flint ....

🤣🤣🤣🤣

[Worty]

Hey worty,

Genuinely sorry to hear about your ongoing problems.

I cannot see a new magneto going wrong in a short period of time in all honesty.

Check all your earths with a multimeter and take a very, very good look at your points and the way they function within the cam housing i.e. no arcing over (at night).

Also check your cut out switch and cable.

P.S.  If you need to you can borrow these, you know where they go.

🤣🤣🤣🤣

[Swarfcut]

 Steel backed points carrier will earth the points if the spring touches the cam ring. Have a good looky look. Circuit is different on the brass backed version so will run even with the spring kissing the cam.
 Mitch with a Hitch is on the money, sticky earth brush also a prime suspect. I would agree that an internal failure is unlikely.

 Swarfy

[Worty]

Checked the earth brush, seems to be ok.  Also, the bike ran well for about 65m before spluttering and running onto one cylinder - this was very similar to the last time the condenser failed although I had to keep the revs right up to prevent it cutting out.  Might just be that the condenser failed prematurely for some reason, or there's another, new fault.  Will check the spring against the backing plate, although last time I looked it was fine.  Is this something that'd happen fairly suddenly??

Cheers guys.

[Triton Thrasher]

Has someone already suggested carbon on the slip ring?

[Worty]

I'll send the maggie back to Andrew as he suggested for it to be double checked.  The reason being I've checked the following:

1.  Two lots of HT leads and pickups against a brand new plug.  I've been using B6HS for 10k miles with no issues.
2.  Earth brush is fine by all accounts.
3.  Points are fine, even checked points from spare maggie, still sparkless.

It does seem strange that the HT lead came away at the same time the maggie appears to have given up the ghost.  I limped home for about a mile on the one cylinder that the HT lead was attached to.  That cylinder occasionally produces an intermittent spark, whereas the l/h cylinder is dead as a doornail. 

Not sure that carbon build up on the slip ring would have caused such a sudden failure - though could be wrong.  Can't think of anything else that can be checked.  Also, last time the condenser failed, I had to keep the throttle wide open to limp home that time.

[RDfella]

As others have said, a fault in the magneto would affect both cylinders (barring a slip-ring issue). I'd be checking things with a multi-meter before going to the hassle of removing / posting / refitting the mag.

[Worty]

True RD, but what else could I check with a multi meter (which I don't have) that wouldn't require removal and examination of the maggie??  I've tried every combination of test I can think of, and nothing's worked.  If Andrew did give it the all clear, I'd still be none the wiser.  After all, apart from earth brush (good), points (good), pick ups (good), HT leads (good) and new spark plugs, surely it can only be the maggie??

[Roger (Doomtrainbarx)]

I'd still give the slip ring a damn good clean. - the problems a "dirty" ring can cause are ridiculous !

[Worty]

I'll give it another go Roger.  My method is clean rag and meths on a finger, spin the motor slowly to avoid too much of a shock.

[RichardL]

First, once Andrew offered to go over the mag there would seem to be no further reason to speculate mag-related issues. While it's with Andrew, go over all the other basic stuff (plugs, HT leads, carb, etc.) When it's back, carefully installed and timed, the problem will likely be gone. If not, more advice will surely folliw.

Richard L.