Restoration of a Bosch ZEV magneto

[duffeycycles]

Pre-'17???? 100 years old in 2016

[10E]

BoschZEV
Congratulations on your friends performance, and your rebuilt magneto he used. It is no easy task getting an old bike across the country given the Cannonball rules.
My magneto performed perfect too, no attention required, even in two days of heavy rain. Never missed a beat.
This magneto has approximately 11,000 miles on it without any attention to it except for points, the majority of those miles being under quite extreme condition ( 8 hrs a day, non stop riding etc) Speaks wonders for the Bosch design and for a stellar rebuild by a man who knows Borsch mags. ( I don't mention his name, out of respect for him) because I believe, due to age he is not looking for any new work.

I have a question, i hope you can answer. Like all mechanical/electrical devices, they can and will let you down at the most unexpected moments. With that in mind.
If you had a total loss ignition set-up installed on the bike (coil/ spark plug wires/ 12 volt battery) in the event the inner parts of the mag failed(armature etc but the mag still turned freely) could it be rigged in a way where you flip a switch and run power from the battery through the mag points to the coil.
I would really appreciate it if you could say if this is possible, and how one would wire this back up system. If not possible I would love to know why not.
I do quite a lot long distance solo riding out in the sticks where cell phones don't work. I don't carry a spare mag. The spare is at home ready to be overnighted if needed. I've been very fortunate in regards to spark, but wouldn't mind have a simple back up spark.
Also, could you mention the pros and cons of lubricating the mag. Type of oil, viscosity, how much, frequency etc.
Thank you in advance.

Your idea for a bike for the 2016 Cannonball is intriguing. Not quite sure from your writing how much you want to charge ( credit) for one mag rebuild.
Since the first Cannonball Run things have changed. Morriss Mags have a very good Bosch replica. My friend Dave Kafton has run the mag twice across the country with no troubles what so ever. There is another Bosch replica too, I don't know anything about this mag. They are both in the $1,200/$1,500 range which I think is a reasonable price for this device.
My 14 HD has over 30,000 miles on it essentially with the same mag the bike came with (except for rebuild) the original owners name is scribed inside the points cover "Young Spindler April 14 1914" Enough said.
I wish you all the best on your bike build. You are correct, now is the time to start work on the 2016 Cannonball. I can tell you this, two days after getting home I was already planning the next Cannonball, and a good long run or two before it. Got some serious climbing to do next spring, 4 passes on The Rockies.
It is a wonderful way to see the USA and it's people.
Regards
Victor Boocock

[BoschZEV]

My magneto performed perfect too, no attention required, even in two days of heavy rain. Never missed a beat.
This magneto has approximately 11,000 miles on it without any attention to it except for points,

Victor,
Thanks for your post. Your experience with the reliability of a properly restored magneto nicely highlights the point I have been making, that these devices are fundamentally quite sound and so there is no excuse if a rebuilt one fails.

Also, could you mention the pros and cons of lubricating the mag. Type of oil, viscosity, how much, frequency etc.

Lucas recommended lubricating their points rubbing block every 3000 miles using oil. I use a more modern silicone-based lubricant sold as Lubricam and would apply a dab at 3000 miles because it is so cheap and so easy to do, although it probably wouldn't be needed. Petrochemicals rapidly erode tungsten points and Lubricam has both a lower vapor pressure and a higher viscosity than any standard organic grease which is why I use it.

Lucas, which also uses the same type of ball bearings, helpfully suggests not bothering to regrease them until the magneto undergoes a general overhaul. But, they neglect to mention at how many miles that might take place. Here I use Sta-Lube high temperature disc brake bearing grease because it is formulated to withstand a much more hostile environment than the grease ever will see in a magneto. Of course, since I have the necessary electromagnet to recharge the magnets, if I had my friend's magneto back in my garage for any reason I'd disassemble it and regrease the bearings at that point just on general principles. But, because of the quality of this grease, normally I wouldn't start wondering about the grease in any magneto I rebuilt until at least 10k miles. Note that I attached a tag to the oil cup on my friend's magneto warning him not to put any oil in it because it only would wash away the higher quality grease that was actually taking care of the bearings.

I have a question, i hope you can answer. …If you had a total loss ignition set-up installed on the bike (coil/ spark plug wires/ 12 volt battery) in the event the inner parts of the mag failed(armature etc but the mag still turned freely) could it be rigged in a way where you flip a switch and run power from the battery through the mag points to the coil.

The answer is an unqualified 'yes' but…

In fact, such "dual use" magnetos were made a century ago, but the switching has to accomplish two things. It has to switch the points into the total loss circuit while simultaneously switching them out of the magneto circuit. Otherwise the 12 V battery would be across the ~0.5 Ohm primary of the magneto whenever the points were open (drawing 24 Amps until the coil melted). This raises the issue of dwell since a magneto fires when the points open while a standard points/coil system fires when they close. The latter needs to have a long period with the points open to give sufficient time for the current in the coil to saturate (given by the ratio of its inductance L to its resistance R), which becomes increasingly important as rpms rise. Anyway, yes, it could be done.

Your idea for a bike for the 2016 Cannonball is intriguing. Not quite sure from your writing how much you want to charge ( credit) for one mag rebuild. … Morriss Mags have a very good Bosch replica. My friend Dave Kafton has run the mag twice across the country with no troubles what so ever. There is another Bosch replica too, I don't know anything about this mag. They are both in the $1,200/$1,500 range which I think is a reasonable price for this device.

I've seen the Morris magneto mentioned on the web but it doesn't show up on their web site. The other one is advertised in the AMCA magazine. I have no experience with either but if they are reliable, and if someone doesn't care about maintaining authenticity, $1500 is certainly less than I would have to charge/credit to justify the time required to properly rebuild an authentic one.

Rebuilding some unspecified number of magnetos in exchange for the parts to build a pre-'16 bike for the next Cannonball is not any sort of standard business offer. But, to the extent numbers can be applied, I suppose we're talking the equivalent of ~$2.5-5k each in trade for parts. What one would get would be their magnetos rebuilt by someone with a Ph.D. in experimental physics who was elected Fellow of the Institute of Electrical and Electronic Engineers for work on magnetic materials and who has over the past fifteen years assembled what is almost certainly the most extensive magneto "R&D facility" on the planet. Whether or not it is "worth" the equivalent of $2.5-5k to have a magneto rebuilt by anyone certainly is a valid question, but it's a bargain compared with my consulting rate. However, my offer isn't about money, it would be to give me an interesting project to do and write about for 'The Antique Motorcycle' (i.e. build a pre-'16 bike from parts; my most recent article on TIG welding is in the current issue).

You are correct, now is the time to start work on the 2016 Cannonball

Exactly. If six months from now someone reads this thread and decides to take me up on this, it will be too late.

[10E]

BoschZEV
I really appreciate your immediate response to my questions. I need time to decipher your answer and come up with a working model. I am pretty much illiterate about electrics but have lots of friends who will interpret you answer into action.
As you say, if Lonnie decides on a pre-16 for a 2016 run, the majority will have Bosch magnetos. As discussed, they do have options in regards to spark generators. But, if you don't have spark, and possibly a back-up system you will not complete the run with a perfect score---if that is ones goal.
One can limp in on one cylinder, fix a flat tire etc and still make the full days ride. No spark, dead in the water.
There are of course catastrophic failures that are unpredictable with 100 year old materials, not much you can do with plain metal fatigue.
I can tell tales of very unusual experiences that would have stopped a motorcycle dead in its tracks and yet nothing untoward happened and I obliviously continued on my way. Incidents that happen on the Cannonball or long distant riding on a daily basis. You have to experience to believe it.
Not all of them are connected to the motorcycle.
This Cannonball, my wallet fell from my clothing somewhere in the middle of Kansas. got to the next gas stop, no wallet, A Cannonballer gave me $20.00,
got to the lunch stop, my fellow team member, Dave Kafton came up to me and gave me my wallet. A farmer had flagged him down ( we were not riding together) saying he found the wallet on the side of the road, when he looked in the wallet he saw my name . How many times would that happen in a life time.
This is the kind of stuff that happens when you are standing on the edge of a volcano.
Don't give up if your plan doesn't come to fruition. I know someone who was willing to rent a qualified motorcycle for 2014 Cannonball (for a fee) leaving the rider with little risk, but of course, no motorcycle ownership at the end of the run. Perhaps another way to riding the Cannonball.
Thanks again and all the best on your project
Victor Boocock

[BoschZEV]

if Lonnie decides on a pre-16 for a 2016 run, the majority will have Bosch magnetos... if you don't have spark ...you will not complete the run with a perfect score... No spark, dead in the water.

That's why there's a chance that someone reading the details of the restoration of my friend's Bosch ZEV might decide my offer makes sense:

http://www.britbike.com/forums/ubbth...733#Post446733

Don't give up if your plan doesn't come to fruition

Not to worry. To call it a "plan" implies more thought than I've actually given it.

Even though I started this present magneto thread only last year it is already #7 in views (and climbing toward #5 within a few weeks) out of all 292 threads in the 'Electrical' forum, indicating a lot of interest in this topic. This brings to mind something else that I'll mention. For several years in the mid-'00s when I was involved with the AMA/AMHF they had me give hour-long magneto (also carburetor) seminars at Vintage Motorcycle Days, and I've also given related talks in Europe and Japan. Two years ago the now-former Blackhawk Chapter asked me to do a magneto seminar at their annual meet, but I already was committed to be somewhere else that weekend. Anyway, I have a talk packed with visuals, sectioned magneto bodies and armatures, a full portable magneto repair toolkit, handouts, etc. in case some chapter is interested in hosting such a troubleshooting and repair seminar for their members at an upcoming meet. I would waive all speaker fees, but it would require covering actual out-of-pocket expenses (i.e. airline ticket, motel, and rental car if one were necessary).

[10E]

BoschZEV
I think all could benefit from a seminar on Magnetos. I will mention it at our next club meeting.
My friends are puzzled by your statement "while a standard points/coil system fires when they close".
Are they confused about this system, or is this a typo.
They are going crazy trying to know the truth. Appreciate your response in advance.
I have a rebuilt spare mag. so I am ready to go to work on setting up a bench test, but need more information on how to isolate the points etc from the mag coil and any other needed information when switching from mag to battery . Any chance of a schematic.
I talked to my friend about a rent a bike for the Cannonball. He's open to a discussion. If interested.
Looking forward to your response
Victor Boocock

[BoschZEV]

My friends are puzzled by your statement "while a standard points/coil system fires when they close".
Are they confused about this system, or is this a typo.

Yes, it's a typo. I had originally written something longer but at the last minute edited it down resulting in that error.

If you simply connected a "standard" battery and coil system to the points of a magneto the ~0.5 Ohms of the magneto primary would be in parallel with the points and the current would divide itself between those two routes according to the relative resistances. If the resistance of the points was very much less than 0.5 Ohms the parallel path wouldn't matter, at least as far as current flow when the points were closed, because most of the current would flow through the low resistance points. However, when the points opened, instead of the current being interrupted, the magnetic field collapsing, and a spark being generated, the current would just reroute itself through the magneto's primary. Now the 12V of the battery would be directly across the 0.5 Ohms and 24 Amps would flow through the magneto generating I^2R = 290 Watts of heat in its coil. If the points are open ~20% of the time as they are with the cam that's in my friend's Bosch ZEV the average heat would be ~60 W. You know how hot a 60 W light bulb is, so imagine the temperature it would reach if covered with insulating varnish and in an enclosed space. That's why the magneto's coil would have to be switched out of the circuit at the same time an external battery system was switched in.

Any chance of a schematic.

I have a very nice schematic for this purpose, and normally it would be easy to upload, but it's a little complicated at the moment. I'll see if I can post something later today or tomorrow. But, the engineering problem you face in trying to accomplish this is that the points in a magneto rotate with the armature while the cam is fixed. It would be much easier if they were fixed and the cam rotated, like in a car's distributor.

[BoschZEV]

Magneto_Battery.jpgI edited/combined two schematics to show both systems side-by-side. The "only" things you have to do are remove the portion of the circuit in red on the left and then connect the points (in green) to the corresponding part of the circuit on the right. Of course, complicating matters is the portion of the circuit in red is the bolt that holds the points to the armature, and the points on the left are rotating at a few thousand rpm while the ones on the right are stationary.

[10E]

BoschZEV
Thank you for the schematic and explanation.
I will work towards making a back-up ignition system using your principles.
Thanks again
Victor Boocock

[BoschZEV]

I will work towards making a back-up ignition system using your principles.

I wrote an article on my extensive toolkit in 'The Antique Motorcycle' a few issues ago so it's not that I don't expect things to break. However, although someone might have a spare carburetor or piston in a chase van on a cross-country ride, few people head out with such parts in their saddlebags expecting to need them for roadside replacement.

I realize electricity is a perplexing subject for many motorcyclists, but there is no reason the electrics can't be at least as reliable as any other part of a motorcycle. You said your current magneto has 11,000 miles on it without problem. I would suggest to people considering having a backup electric system that rather than hoping a "belt and braces" approach might keep the electrics working, where neither the belt nor the braces has passed inspection, it would be better to concentrate on having a proper belt in the first place. As you have experienced yourself a proper belt, er, I mean, magneto, will be reliable for many thousands of miles.

At best, whatever your friends do when messing with your magneto to equip it to also run a backup battery ignition system won't inadvertently make your magneto less reliable. But, my worry is that it will. Still, if you do proceed with this, please don't forget to post photos of what the modification looks like.

[10E]

I wrote an article on my extensive toolkit in 'The Antique Motorcycle' a few issues ago so it's not that I don't expect things to break. However, although someone might have a spare carburetor or piston in a chase van on a cross-country ride, few people head out with such parts in their saddlebags expecting to need them for roadside replacement.

I realize electricity is a perplexing subject for many motorcyclists, but there is no reason the electrics can't be at least as reliable as any other part of a motorcycle. You said your current magneto has 11,000 miles on it without problem. I would suggest to people considering having a backup electric system that rather than hoping a "belt and braces" approach might keep the electrics working, where neither the belt nor the braces has passed inspection, it would be better to concentrate on having a proper belt in the first place. As you have experienced yourself a proper belt, er, I mean, magneto, will be reliable for many thousands of miles.

At best, whatever your friends do when messing with your magneto to equip it to also run a backup battery ignition system won't inadvertently make your magneto less reliable. But, my worry is that it will. Still, if you do proceed with this, please don't forget to post photos of what the modification looks like.

BoschZEV
What damage is possible when trying to set up this type of system. It would be good to know before firing it up.
The scenario is-- Riding by myself, the mag quits on Utah on Hwy 50, the armature shaft still rotates, your 98 miles from anywhere, the cell phone doesn't work, you only see another person every 45 mins. and they don't always stop to help. In 10 mins the back up is working and it gets you back home 1000 miles away. or it gets you to the night stop where a back-up mag can be delivered, if needed.
This is not a dream, I've done it three times, without trouble. Maybe the 4th time, next spring, I won't be quite so trouble free.




Whoops-- All change, maybe.
Whilst my mag as proved to have been rebuilt in the correct manner and still continues to spark reliably I still maintain that trying to finish a Cannonball day or get to home base after a 400 mile day it would be a great help having a quick change back-up system.

Having a "proper belt".
Keeping in mind if the 2016 Cannonball is a pre-17 event there will be a lot of magneto bikes entered. For the best enjoyment of the riders it would be great if the problems of the 2010 magneto problems are not repeated.
You have covered a rebuild that would help prevent this from happening. Riders would do well to at least read up on your articles whilst there is is good time to take it all in and get their mags in good order.
I was talking to 2014 Cannonballer Joe Gimpel about mags and other things too.
He mentioned something that really shook me. He said he thought many of the 2010 riders had mag problems due to the fact that they used the wrong bearing grease. He saw disassembled mags with High temp moly grease in the bearings ("this grease will conduct electricity" Joe said) Only dielectric grease should be used in a magneto otherwise arcing of the bearing and besides pitting of the balls, will lead to other problems.
To a non informed Joe's thoughts made a great deal of sense, and I believe I read some where that Mr Bosch went to a great deal of trouble by installing a device to help eliminate this problem.
I know that condensers appeared to be part of the problem too, but non the less if Joe is correct, The un-informed people may have never stood a chance of a reliable mag.

Just to throw a spanner in the works. We talked about a back-up system. He mentioned he had made one for his Bosch mag in the past, and used it. ( batt. and coil set-up)
His system, using isolation parts etc uses the existing points assembly. He said it worked fine, in fact, he lent it to a friend 2 years ago whilst his mag was being re-built, in Germany. and the back up system as been working ever since.
Would appreciate your feeling about both the grease issues and Joe's back-up system.
The reason for this conversation is I would like to see all Cannonballers and others have the least amount of trouble with mags
Regards
Looking forward to your reply
Victor Boocock 10E

[tfburke3]

BoschZEV
What damage is possible when trying to set up this type of system. It would be good to know before firing it up.
The scenario is-- Riding by myself, the mag quits on Utah on Hwy 50, the armature shaft still rotates, your 98 miles from anywhere, the cell phone doesn't work, you only see another person every 45 mins. and they don't always stop to help. In 10 mins the back up is working and it gets you back home 1000 miles away. or it gets you to the night stop where a back-up mag can be delivered, if needed.
This is not a dream, I've done it three times, without trouble. Maybe the 4th time, next spring, I won't be quite so trouble free.




Whoops-- All change, maybe.
Whilst my mag as proved to have been rebuilt in the correct manner and still continues to spark reliably I still maintain that trying to finish a Cannonball day or get to home base after a 400 mile day it would be a great help having a quick change back-up system.

Having a "proper belt".
Keeping in mind if the 2016 Cannonball is a pre-17 event there will be a lot of magneto bikes entered. For the best enjoyment of the riders it would be great if the problems of the 2010 magneto problems are not repeated.
You have covered a rebuild that would help prevent this from happening. Riders would do well to at least read up on your articles whilst there is is good time to take it all in and get their mags in good order.
I was talking to 2014 Cannonballer Joe Gimpel about mags and other things too.
He mentioned something that really shook me. He said he thought many of the 2010 riders had mag problems due to the fact that they used the wrong bearing grease. He saw disassembled mags with High temp moly grease in the bearings ("this grease will conduct electricity" Joe said) Only dielectric grease should be used in a magneto otherwise arcing of the bearing and besides pitting of the balls, will lead to other problems.
To a non informed Joe's thoughts made a great deal of sense, and I believe I read some where that Mr Bosch went to a great deal of trouble by installing a device to help eliminate this problem.
I know that condensers appeared to be part of the problem too, but non the less if Joe is correct, The un-informed people may have never stood a chance of a reliable mag.

Just to throw a spanner in the works. We talked about a back-up system. He mentioned he had made one for his Bosch mag in the past, and used it. ( batt. and coil set-up)
His system, using isolation parts etc uses the existing points assembly. He said it worked fine, in fact, he lent it to a friend 2 years ago whilst his mag was being re-built, in Germany. and the back up system as been working ever since.
Would appreciate your feeling about both the grease issues and Joe's back-up system.
The reason for this conversation is I would like to see all Cannonballers and others have the least amount of trouble with mags
Regards
Looking forward to your reply
Victor Boocock 10E

As Bosch ZEV stated the spinning points and condenser in the bosch mag,at least in my FFVRS,complicate things.With no wires to the spinning points I see no way to make this work to switch over to battery coil ign.without extensive modification.
However a mag with fixed points and spinning cam are easily converted to wasted spark or a distributor,but in my opinion not a road side switching situation.
Tom
Tom

[BoschZEV]

What damage is possible when trying to set up this type of system. ...
The scenario is.... In 10 mins the back up is working and it gets you back home...

Yes, I realize that's the scenario you're hoping for. My own hoped-for scenario also would have a gourmet cook drive by during those 10 minutes and serve a delicious snack while my butler dealt with the ignition system. But, the reality is more likely to be that the system your friends cobbled together would look good but would fail in short order taking an otherwise perfectly functional magneto with it because of some defect in the design/implementation that hadn't been apparent.

I was talking to 2014 Cannonballer Joe Gimpel about mags and other things too... He said he thought many of the 2010 riders had mag problems due to the fact that they used the wrong bearing grease. He saw disassembled mags with High temp moly grease in the bearings ("this grease will conduct electricity" Joe said) Only dielectric grease should be used in a magneto otherwise arcing of the bearing and besides pitting of the balls, will lead to other problems.

I'm sorry to say this about your friend but this is a case where a little knowledge is a dangerous thing.

If you look at the schematic I posted a few days ago you will see a connection to ground (earth) of the primary coil on the armature. This is needed because the current from the spark plug needs some way to get back to the primary after jumping the gap in order to complete the circuit. If you look at the following link in my restoration thread you will see this ground connection is provided by the sliding contact of a carbon brush on the back of the rotating points plate:

http://www.britbike.com/forums/ubbth...359#Post450359

If that brush weren't there and if the outer race of the bearings weren't insulated from the body of the armature, the path the current would take would be through the outer race, through the balls, and through the inner race to the shaft of the armature. Even though that current is small, it happens ~2000 times/minute so it would slowly cause pitting of the balls and race. This much your friend got right. However, that brush is there. But, this isn't the only thing he got wrong.

Although molybdenum disulfide grease has some electrical conductivity, it is very small. Still, grease slathered between the body of the magneto and making contact with the balls would carry some electrical current in parallel with that being carried by the carbon brush. However, when a current is faced with the choice of two parallel paths it divides in proportion to the resistances of those paths. Because the conductivity of the moly grease is so small, the resistance of the "ball bearing" path would be very large so the current through that path would be very much smaller than that through the brush. Because of this, the time required for this tiny current to cause pitting would be huge.

This is to be contrasted to the concern I'm sure your friend had read about but had misunderstood. If the bearing had been installed without an insulating cup between it and the housing the current would have the choice of a path through the carbon brush and an entirely-metallic path through the bearing. If that were the case, most of the current would take the lower resistance path through the bearing.

However, he got it even more wrong than the above since the dielectric grease he told you to use isn't designed for lubrication of bearings, but rather for one-time uses like lubricating a spark plug boot so it slides on easier, or smearing over an aluminum electrical connection to keep it from oxidizing. While I don't recommend moly grease for a magneto, using dielectric grease to lubricate the bearings would trade the essentially hypothetical failure mode of pitting that with moly only would happen after many tens of thousands of miles, with the very real failure mode of rapid wear of the bearings due to use of a completely inappropriate grease.

To a non informed Joe's thoughts made a great deal of sense, ... He mentioned he had made one for his Bosch mag in the past, and used it. ( batt. and coil set-up)
His system, using isolation parts etc uses the existing points assembly.

I would have to see photographs of the system Joe said he built before I could comment on it because as tfburke3 wrote:

With no wires to the spinning points I see no way to make this work to switch over to battery coil ign.without extensive modification.

Also,

I would like to see all Cannonballers and others have the least amount of trouble with mags

My sentiments exactly.

[10E]

BoschZEV
Thanks for the continuing advice and opinions.
Quick question.
What type and grade etc. grease do you use on the armature ball bearing races.?
Thanks in advance
Victor Boocock
PS if you have mentioned it in the past posts I must have missed it.
More to come on the back up system.

[BoschZEV]

What type and grade etc. grease do you use on the armature ball bearing races.?
PS if you have mentioned it in the past posts I must have missed it.

I did mention it in an earlier post but I'm happy to repeat the information. I use Sta-Lube high temperature disc brake bearing grease because it is formulated to withstand a much more hostile environment than the grease ever will see in a magneto.