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Discussion Starter · #1 · (Edited)
EDIT: This is my first attempt on doing a "TECH" so, as I go along and find topics that are important, I'll add and edit.
After searching thread after thread and not finding much help and Trent helping as much as he could, I decided to put together a thread on trouble shooting a magneto.

As Trent said, "They are pretty simple and dependable." He's right, when they work, when they don't....Well, it's head scratching time.

OK, here is the Magneto that I am using on my build, SOLO.


Ya this is a learning curve thing.
After doing a hell of a lot of research I've found out that I have a Joe Hunt Magneto on a Morris Magneto cam chest cover with a Morris Magneto bake lite cover, kinda a mix and match deal.

If you look close at the pic, on the front of the mag there are holes for screws, these hold the coil in place on the forged Hunt style mag case. Although I've never been inside a Morris, they tell me that they have internal screws that hold the coil in place.


A diagnostic tech tip page.
Tech tips

Testing Output with Magneto Installed & Timed:

Leave spark plugs in to maintain a compression stroke. Since the engine will tend to snap through once the compression is overcome, this will properly time magneto thrust cycle. NOTE: Bear in mind that testing without spark plugs installed, along with testing by hand-spinning a removed magneto, may give intermittent output results, since the magneto cycle is begun at a random point.

The above does not apply to the fully automatic M5 and G5 type magnetos, since they are self-timing and self-thrusting at Iow speeds. battery, to the magneto's kill stud can damage coil and/or rotor. Physically check for cracks or leakage (burn spots) on coil, Setscrews holding coil in housing should be snug. Coils are typically either "good" or "dead" Primary coil resistance (wire to ground tang at core) should read around 0.3 ohms. Secondary resistance should read around 13,000 ohms. You will need a meter capable of reading very Iow resistance (tenths of ohms)

Magnetic Rotor: Constructed using alnico and/or rare earth magnets, a very 'permanent' magnetic material. While unlikely, 12 volts to the coil (as outlined above) could damage the rotor's magnetic charge.

The magneto's secondary high-voltage coil is "floating": ground is only used to complete the circuit between the spark plugs. Therefore, spark occurs between one spark plug wire and the other. Use spare spark plugs tied together, or a bridged gap of 0.200 inch (5 mm) or more, to test for sufficient starting voltage. Bear in mind, the slower the motor and/or magneto is turned, the lower the voltage output. We normally test output at a constant speed of 400 engine RPMs, using an oscilloscope to measure voltage. At that speed, output should be a minimum nominal 15,000 to 20,000 volts NOTE: Never run magneto at high speed (lathe, drill press, etc.) without a secondary electrical path; internal cap or coil carbon-tracking can result. Condensor: Can be shorted (no spark), open, or of diminished value, thereby lowering output and/or point life. When in doubt, swap it out. We recommend replacement when points are replaced, as preventative maintenance. OEM type recommended.

Points: Typical life 8,000 to 10,000 miles (15,000 km), unless point itself loosens in holder, or points become pitted or contaminated. Normal service finish is dull gray. The A/C spark at points helps 'burn' themselves clean. NOTE: Resistance, causing no or Iow output, is often the inadvertent result of someone doing a poor points-dressing job. Replace. only with OEM type points.

Morris Magnetos are non-vented units; best results in keeping moisture out are with an uncracked stock type Bakelite cap and cork gasket. Inspect carefully. Keep in mind that if water gets in, it will have difficulty getting out. Additional water may lay on the bottom, under the coil

Component Check:

Other check-points: Disconnect kill wire from stud to isolate any rubbed-through wires, grounded switches, etc., which may be grounding out magneto. Also, note that points leaf spring comes close to one of the points plate hold-down screws: ensure that they do not touch. Typically, this will happen if leaf spring is bent downward, or if wire terminal crimps are stacked, causing the spring to be bent inward when cap is installed Coil: Normally long life. A connection of the motor- cycle's 12 volt system, particularly if you have a battery, to the magneto's kill stud can damage coil and/or rotor. Physically check for cracks or leakage (burn spots) on coil, Setscrews holding coil in housing should be snug. Coils are typically either "good" or "dead" Primary coil resistance (wire to ground tang at core) should read around 0.3 ohms. Secondary resistance should read around 13,000 ohms. You will need a meter capable of reading very Iow resistance (tenths of ohms)
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Discussion Starter · #2 · (Edited)
Spinning it by hand, I was getting no fire so I replaced the points and condenser, after talking to the Morris tech I found out that I had bought the "cheep" set and although they would work, well like they say, ya get what ya pay for so, the high out put condenser and good points are on the way.


Taking the points out, I found out that two of the screw holes were striped out, so a new plate is in order.




This is a right hand points plate, It's my understanding that the Sporsters have a left hand plate.

Keep everything together and sorted.
 

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If you look close at the pic, on the front of the mag there are holes for screws, these hold the coil in place on the forged Hunt style mag case. Although I've never been inside a Morris, they tell me that they have internal screws that hold the coil in place.
The earlier Morris heads (cast) had set screws. The later billet models didn't. All Joe Hunts on the other have them. If it's a billet body, with set screws, it's a later Joe Hunt with rare Earth magnets.

I actually picked up what I was told was a MM74E on the cheap, but had the same situation. Morris base (retardable generator style) with a Hunt billet body magneto (set screws for the coil, rare Earth magnet). After I talked to Dave at Morris (I've had them rebuild two for me in the past), I decided to send it to him for a once over. He's the one that told me the trick about telling the difference. He also told me some other important differences regarding the Hunts and Morris mags. I had him pop in some new points and a condensor and send it back.
 

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Discussion Starter · #4 · (Edited)
Dawg, thanks for the heads up, like I said, I'm learning as I go on this so PLEASE----Everyone that has any info that you can shine on it, feel free to do so. How do you tell if its a cast or billet housing?


Doooogh......After ya posted the answer it hit me, lol....Ya'd think after a machine tool class and two years apprenticeship in tool and die I'd have remembered that....
 

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Discussion Starter · #5 · (Edited)
Kill switch wire removed along with the coil.


Make sure that ya keep all of the insolaters together for this.


After taking it this far, decided to go ahead and inspect the lower end bearing.

The dust cover is crimped in place, take a screwdriver and pop it out.
Old grease and dirt, rolled like it was on gravel, damn glad i
I took it out.



After I took the clip out, I Cut off a hex key and used that to drive the rotor out.

Shit I found.

 

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Well, casting marks versus tooling marks. The one you're holding up looks like a cast body, but both were based on, and even used if you go back early enough, Fairbanks Morse magneto heads. Even the parts are interchangeable for the most part. You could have a Hunt body with all Morris guts, or vice versa. The body of that head is a dead ringer to the one on my Shovel's M5, which is an early cast Morris model with new guts.

I'd send those pics to Dave Shaw and see what he says.
 

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Discussion Starter · #7 ·
Fantastic info right there, Thank You!
 

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Discussion Starter · #8 · (Edited)
The lower bearing is held in with a c-clip.


After taking it out, time to remove the bearing. Gona replace it anyway so a socket and dead-blow hammer will work.


Seen better days.
 

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Discussion Starter · #9 · (Edited)
A little surface rust, should clean up.



Ok, now that it's apart, I can make a list of what needs replaced, order and see if I'm worth a shit on rebuilding this.
 

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Awesome. I have several mags and pieces I need to put some together. Thanks for putting this up. What do they charge to rebuild one. Close price I know you can't give an exact price.
It really depends on what is needed, what you have already, what you're looking to do with it, etc.

For instance, if you have one with a good rotor that they can charge up, but the coil, points, condensor, and bearing need to be rebuilt, it will cost you a couple of hundred bucks. While they're in there, they can put in a rare Earth magnet rotor for a couple of hundred more. One thing to consider is buying used and having them basically refurb it to their new standards. I did that with an M5 setup and basically came out about $600 cheaper than buying a brand new one, and that was with new bearing, seals, rare Earth rotor, points, coil, condensor, install kit (cam cover, gear, screws, pins, etc.). On the one on it's way back now, I will come out about $400 cheaper than a brand new setup (MM74E) and it will essentially be the same, other than the head being a Joe Hunt (the points, condensor, lexan cover are all new Morris and it has a rare Earth rotor already that was checked).
 

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As seen in the pics, it's a straight forward deal. I have never sent a mag anywhere. Get the exploded view and review what you have. Rotors rarely go bad. If I had one that was weak, I would replace with a rare earth anyway.

Sixball
 

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As seen in the pics, it's a straight forward deal. I have never sent a mag anywhere. Get the exploded view and review what you have. Rotors rarely go bad. If I had one that was weak, I would replace with a rare earth anyway.

Sixball
They don't charge a whole lot for the labor and generally they can tell when something is shit and will replace it.
 

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They don't charge a whole lot for the labor and generally they can tell when something is shit and will replace it.
My mags, my labor, so I figgure the labor is free. And I can always tell when something is shit, not just generally. And I can replace it too. Just sayin.......

I'm not telling anyone what to do, just pointing out that mags are pretty straight forward, and the OP proved that with the pics and minimal comon hand tools used to take it apart.

Anyone is free to send it off, or do it yourself.

Mags just seem to be viewed by alot of people as some super complex piece of technology that can only be serviced by Two companies.

My opinion. I'm not wanting to take away from the OP's intention on the thread. It's imformative in showing the simplicity of the "inards" of a mag, yet the topic of sending ones mag off to be rebuilt comes up?

Sixball
 

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My mags, my labor, so I figgure the labor is free. And I can always tell when something is shit, not just generally. And I can replace it too. Just sayin.......

I'm not telling anyone what to do, just pointing out that mags are pretty straight forward, and the OP proved that with the pics and minimal comon hand tools used to take it apart.

Anyone is free to send it off, or do it yourself.

Mags just seem to be viewed by alot of people as some super complex piece of technology that can only be serviced by Two companies.

My opinion. I'm not wanting to take away from the OP's intention on the thread. It's imformative in showing the simplicity of the "inards" of a mag, yet the topic of sending ones mag off to be rebuilt comes up?

Sixball
I gotcha. Honestly, the first mag I had, I sent it to them because I did view it as some sort of voodoo. I sent them the next one because I wanted to have all new guts put in it since it was going to be starting a kick only 100ci Shovel. The next one...well, I thought they've done me right before and I'd kinda like to know what I'm working with.

It's not a fear issue, just trust in a good company. The more I've learned, the more I'll do myself.
 

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Discussion Starter · #16 · (Edited)
The reason I started this post is like Dawg said, I've never been inside one and have always felt like it was some kind of vo-do, high tech, best left to the pro's sort of thing. Well as I have aged, the fear of failing isn't quite as strong as it once was and with no disrespect towards anyone, do I really give a shit what anyone else thinks if I do fail? That plus my Dad's voice is ringing in my ear, "Well ya damn well can't if ya don't try."

Not that it really matters to anyone else besides me, I've been thinking of my best friend, my mentor, my Dad a lot lately. Ya see, he was a man that could/would fix anything/anytime/anywhere, for no other reason then he could and after he was done, he'd have that half grin and sparkle in his eyes, the satisfaction of a job well done. He was also a man that took the time to show/explain what and why he was doing what he was doing while I was handing him wrenches.

So anyways, after the parts get here and I get it back together....
 

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Discussion Starter · #20 ·
Here is what I have for bearings.

TOP; made in Japan, TRI13307E, TXO G
Dust cover on both sides. OD-1.180, ID-.690, HIGTH-.273
Threw Morris, p10 is 37.95.
BOTTOM; made in Romania, PEER, 7109
Dust cover on one side. OD-1.736, ID-.586, HIGTH-.351
Threw Morris, p14 is $24.95.
 
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