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Magneto question #481625 03/16/13 7:57 pm
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Red Lapierre Offline OP
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A mag with spark with (with correct timing)auto advance if its not returning to full retarded position could that make it hard to start or not start at all?

Do you prefer auto to manual advance??

Thanks to all


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Re: Magneto question [Re: Red Lapierre] #481633 03/16/13 8:44 pm
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No.

That situation might make it prone to kick back, but wouldn't make it reluctant to fire.

Last edited by triton thrasher; 03/16/13 10:17 pm.

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Re: Magneto question [Re: Red Lapierre] #481932 03/18/13 11:54 pm
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If a mag has spark when kicking over bike or spinning on a drill does it mean the condenser is ok and mag should work?


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Re: Magneto question [Re: Red Lapierre] #481942 03/19/13 1:26 am
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There's a qualifier in there Red.....

Sure, it MIGHT be good....

But, it might not be as good as you'd like, because if it is tired and breaking down, once the mag got up near running temps, the condenser may fail when heated up.
Even after letting the mag cool down again.
You might get a restart, many times, but it will NOT let you go far at all...
Brett

Re: Magneto question [Re: Red Lapierre] #481949 03/19/13 1:53 am
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The mag seem ok started the bike several time and now don't seem to start motor. Is there a way to test? I have a local autoelectric place I'm thnking of taking it to.


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Re: Magneto question [Re: Red Lapierre] #481950 03/19/13 2:05 am
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Open a spark plug gap to about 5 mm,and see how it sparks.
You can still get a spark with a bad condensor;it will just be a weak spark.

Re: Magneto question [Re: Red Lapierre] #481972 03/19/13 6:41 am
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Originally Posted by Red Lapierre
The mag seem ok started the bike several time and now don't seem to start motor. Is there a way to test? I have a local autoelectric place I'm thnking of taking it to.


Most auto electric places have nobody who knows anything about magnetos.


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Re: Magneto question [Re: triton thrasher] #482000 03/19/13 2:15 pm
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....
If you live near an airport, and they have repair facilities you can find AND access, you might try to find an engine repair shop, and see if'n anyone in there knows anything about mags... Or knows someone who knows about mags...

Engine repair/rebuilding shop.

Re: Magneto question [Re: Red Lapierre] #482041 03/19/13 8:50 pm
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My local autoelectric does mag repairs. So he is going to check it out. If I need parts does anyone know where to get them? Does some supply Lucas mag parts?

Thanks


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Re: Magneto question [Re: Red Lapierre] #482042 03/19/13 8:52 pm
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Originally Posted by Red Lapierre
My local autoelectric does mag repairs. So he is going to check it out. If I need parts does anyone know where to get them? Does some supply Lucas mag parts?

Thanks


He'll know where to get parts.


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Re: Magneto question [Re: triton thrasher] #482046 03/19/13 9:44 pm
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And, I'll suggest they do NOT try to get OEM Lucas wax paper condensers! 50+ years on the shelf?

There are better replacements out there...

Re: Magneto question [Re: Red Lapierre] #482050 03/19/13 10:17 pm
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Originally Posted by Red Lapierre
My local autoelectric does mag repairs. So he is going to check it out.
I noticed this thread a few days ago but haven't had time to respond. You should read the information I posted on magneto repairers at:

http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=464907#Post464907

It's not likely your local autoelectric shop repair shop has experience with rotating armature magnetos, but reading the information on the above link will help you decide whether or not they actually do.

You can do a reasonable test of your magneto by connecting it to a variable speed electric drill using a piece of rubber tubing. Turn it the correct direction and have it connected to a ~5 mm spark gap. If it jumps the gap back to earth above 1000 rpm and you see only tiny pinpoints of sparks across the points the magneto itself likely is fine. If it doesn't jump the gap as you speed it up, or you see sparking across the points, stop the test and let us know what you observed.

Re: Magneto question [Re: Red Lapierre] #482066 03/20/13 12:15 am
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The rubber hose to protect threads? I did spin it with a drill and plugs on grounded to body of mag and yes there was a spark across both plugs gapped at.018 and small spark at points gapped at .012. Occasionally one across near contact breaker assembly to housing but rare. I had the mag in motor started several time ran great timing seemed ok I did not rode test it but ran for several minutes a good 15 to 20 times. I did not start it for a month or so (drain oil from sump) then I could not get it to start, plugs came out wet so I check for spark had one but seem weak. So I pulled mag and tested with drill had a 2nd mag tested with drill it did the same thing both sparks look the same. I dried plugs several time and kicked over and over popped once then nothing. I though it might be flooded but it was starting on 2nd or 3rd kick till I let it set for a month.

Thanks for all the response.
Red
This Autoelectric place has done other mags on all kind of things. They are very well know here 30 years in business. I know that don't mean they know these.


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Re: Magneto question [Re: Red Lapierre] #482108 03/20/13 12:38 pm
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Originally Posted by Red Lapierre
The rubber hose to protect threads? I did spin it with a drill and plugs on grounded to body of mag and yes there was a spark across both plugs gapped at.018 and small spark at points gapped at .012. ...I did not start it for a month or so (drain oil from sump) then I could not get it to start, .
A couple of quick points. You really do need to test it with a gap of 5mm. The voltage required to jump the gap is considerably larger in the ~150psi of the engine than in the 14.7psi of air. Second, if you didn't drain the fuel from the float bowl, the problem easily could be due to a plugged pilot jet and/or lack of volatiles in the fuel. They evaporate off very quickly. The remaining fuel burns, but is much more difficult to ignite.

Re: Magneto question [Re: Red Lapierre] #482133 03/20/13 5:28 pm
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I did drain bowl and tank and put new HT gas. Carb is new.
I'm waiting for him to test cap or clarifier.
Should know by next week.

I did try new plug because they were new but could be that too.


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Re: Magneto question [Re: Red Lapierre] #482276 03/21/13 2:17 pm
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Magnetoman
I did you 5mm gap on a mag I clean up to try and it does jump the gap at any speed on the drill. I also noticed that I see a spark on points spinning by hand too. I will install and see if it starts.

Thanks for all the help


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Re: Magneto question [Re: Red Lapierre] #482280 03/21/13 2:54 pm
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Originally Posted by Red Lapierre
I did you 5mm gap on a mag I clean up to try and it does jump the gap at any speed on the drill. I also noticed that I see a spark on points spinning by hand too. I will install and see if it starts.
Even a magneto with a good capacitor will exhibit tiny pinpricks of spark across the points. What a bad capacitor will do is allow larger sparks than that. I realize that without experience trying to decide if "tiny" sparks are "too large" is difficult, but anything more than tiny pinpricks point to the condenser.

Originally Posted by Red Lapierre
I did drain bowl and tank and put new HT gas...
I did try new plug because they were new but could be that too.
Two points: if the gas sat in the float bowl for more than a week or so before you drained it, that could be long enough for the pilot jet to be clogged. Second, and without trying to start a discussion on what brand is best, I recommend you try it with new NGK plugs gapped to 0.018".

To help get the ball rolling in a case like this, a squirt of ether "starting fluid" can make all the difference. If you don't get a response with ether it indicates no spark at all is making it to the plugs, and it points to an electrical issue (e.g. cracked plug wires shorting the spark to the frame). If you do get a response, but it only fires a couple of times it points to a fuel issue (e.g. plugged pilot jet).

Re: Magneto question [Re: Red Lapierre] #482291 03/21/13 4:20 pm
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I will get NGK plugs I have champion now. I try ether and nothing happen which is why I pulled mag most everything is new wires, plugs, carb, oil pump and recently rebuilt motor too. I will check jets.
She getting back at me for letting her sit for 20 + years while I rode my HD she sat on the bench with seized pistons. The company that did the motor work went out of business shortly after so I had no warranty.

Thank you for all the help.
I hope to get at it this weekend.


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Re: Magneto question [Re: Red Lapierre] #482368 03/22/13 1:01 am
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Does anyone know where to buy a capacitor for the mag? One of my mags tested bad capacitor and the other was both coil and cap bad.
Thanks


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Re: Magneto question [Re: Red Lapierre] #482378 03/22/13 2:15 am
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Originally Posted by Red Lapierre
Does anyone know where to buy a capacitor for the mag?
No promises, but I'll try to get information to you by this weekend of a suitable replacement capacitor that is cheap, available, and has the proper specifications for use in a magneto. It won't have been subjected to tests, but will be similar in design and construction to a no longer produced one that has been.

Update: I took some time to look through my files and to check several places on-line. I was too optimistic in saying I will have the information ready by this weekend. It will take quite a bit more time than I had anticipated to gather updated information, and I'm just not going to have that much free time for a while. It will be at least two weeks, and maybe not even until the end of April. Sorry.

Last edited by Magnetoman; 03/22/13 4:48 am. Reason: updated date I'll have information
Re: Magneto question [Re: Red Lapierre] #482405 03/22/13 9:46 am
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No apology needed.
I happy for the info you and this forum have given me already. The trick part will be how to get it apart with out ruining it. On simple design change would make it easy to get at. Swap where the screws are to dismantle put the screw head on the other side take 2 screw out spread apart and condenser would be right there. Not sure how to get the spark plug contact apart.


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Re: Magneto question [Re: Red Lapierre] #482442 03/22/13 3:07 pm
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Originally Posted by Red Lapierre
The trick part will be how to get it apart with out ruining it...
Judging from quite a few boxes of parts that I have seen, many people did not master the trick. Getting the armature out without damage is the first task. It's easy if you first remove the pickups and the necessary screws. In particular, the two emergency gap screws that stick down into the slip ring have ruined more slip rings than all other causes combined.

Removing the armature should not require any force. If you feel resistance, it's almost certainly because you forgotten to remove something. If there is resistance, don't push/pull harder; stop to find what is causing the resistance. If it's because you failed to remove both safety gap screws, they will break the slip ring.

Re: Magneto question [Re: Red Lapierre] #482459 03/22/13 4:57 pm
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Red, do you mean the condenser or capacitor?

Bill


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Re: Magneto question [Re: Red Lapierre] #482484 03/22/13 7:08 pm
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Magnetoman Not sure how to get the spark plug contact apart.My mistake should of said slip ring.
I was talking getting the armature apart not get it out.The 2 screws that hold armature together are under the slip ring so you have to pull slip ring off to get to them and the wiring from coil to slip ring is attached if the screw were put in from drive side you could get at it easy.
Boomer
Condenser is what in book but I think they both have the same function store energy.

Last edited by Red Lapierre; 03/22/13 7:12 pm.

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Re: Magneto question [Re: Red Lapierre] #482496 03/22/13 7:45 pm
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Originally Posted by Red Lapierre
Not sure how to get the spark plug contact apart.My mistake should of said slip ring.
Take a look at the following:

http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=458761#Post458761

In fact, if you haven't already done so, it would be worth your while to go through that entire thread before proceeding. There are some detail differences between it and the Lucas you're working on, but overall they are quite similar.

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