Magneto problem
- Thread starter Oldhaven
- Start date
Two days ago after a gestation period of over two decades in my cellar the '48 Rapide was birthed out of the steep cellar door with the help of three very strong guys and a winch. It was still a difficult birth, but everything came up that narrow concrete staircase undamaged. I expected that after a swat of the kickstart it would utter its first cries, but not so much as a sputter. So I have spent the last two days troubleshooting and wearing myself out on the kickstart. Most apparent cause: No sparks, even when I used a bare ignition wire from the pickups to the cases. Expecting mag trouble I took it off and put it in a vise, running the bare wire to the vise. I spun it by hand and presto, a good spark from both pickups. Put it back on the bike, timed it and Drat! no spark with the bare wire or the plugs. I thought maybe I just was not seeing a spark in the sunlight, so tried it all together and after about 30 swings I got a backfire. Then nothing for about 30 more swings or until I am about to fall over. Removing the plugs shows no sparks again. I tested the grounding of the mag to the cases and got good continuity with the meter. The points are set correctly at .012 and the timing is pretty well set by using a degree wheel. Really I should expect if it works in a vise it would work on the bike. What am I missing?
Ron
Ron
Sadly these days "a fresh complete rebuild" of any old component is no guarantee of good working order. (No disrespect to whoever did the rebuild.)
It does seem rather strange that you can produce a spark in the vice on the bench but not on the bike itself. How fast are you spinning it by hand on the bench? Perhaps at kick starting speed it is not spinning fast enough.
Thanks vibrac, I see where you are going and my next move is to try it on the vise with the same plug leads, caps and plugs I intend to use. Fewer variables. Still I did try the same bare wire on the bike that I used successfully in the vise and no joy. I will also use the plug wires to the body of the mag on the bike to double check grounding. I have also been advised not to use just one wire as it may damage the mag despite the earthing screws, so I will be using both from now on.
For Ed, not spinning fast on the bench, but likely faster than kick starting.
Ron
For Ed, not spinning fast on the bench, but likely faster than kick starting.
Ron
Hello Ron, Super Job, Are you sure you have not got the leads on the wrong plugs, Sorry, But a lot of us have done it, Cheers Bill.
If it were mine, I would remove the contact breaker, inspect the "points", give them a light rub with a fine oilstone. The rebuilder may well have put some preservative on them . Been caught myself. Roy.
I have the right leads to the plugs, checked that last month after hearing of others problems... and I did remove the points and got them to a fine platinum polish yesterday. Still no go. I'm giving it a break right now before removing the mag for more bench testing. I'll get there, and have the Norton dual points setup I discussed last year to fall back on, but I do want to use the lucas mag if I can. I had one on my first Rapide and it acted fine for years even though it was pretty clapped out.
Of course the weather is perfect for riding right now.
Ron
Of course the weather is perfect for riding right now.
Ron
Is your breather slipping and not spinning the ATD?