Joe Hunt magneto

Schwany said:

Alrighty then. Certainly, easier that putting one behind the cylinders. Very fiddly install there. I've got all the parts to make it possible, but no interest in ever using one again.

Avoid doing a low side in a right hander. Probably not likely to happen on a track day bike unless the motor or rear hub locks up.

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Fast Eddie said:

Yes, as Ken has proved, if it goes down on the timing side it will most likely knock the mag off. But according to those who have done it with the Joe Hunt, that’s pretty much all that happens, the cases etc aren’t really at significant risk it seems.

So re-fitting or replacing the mag will just have to be factored in to the ‘cost of crashing’ equation !

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ashman said:

I have owned my Norton since new, started with points system then first EI a Lucas Rita system lasted 11 month before it crapped itself, lucky not far from home, then replaced it with a Boyar was good till the big fire of 82 bike was off the road for rewire and waiting for the seat to be rebuilt one week later 100 miles from home the Boyar crapped itself, replaced it with another Boyar that was in the bike for over 30 years without any problems except a few battery failures, I have a JH on my 81 Triumph and its was so good, 9 years with 250K km on it with that JH only doing general maintenance, and to now the new 4 rare earth JH on the Norton with over 35k mile on it with out touching it except for taking the front cover off to check on the point and few drops of oil on the points cam felt pads.
My conclusion is the last boyar was good not problems with it except a few batteries letting me down, the boyar was still going when I replaced it with the JH, my Norton is my hotrod bike, built for lightness in the Featherbed frame, worked motor, the JH puts out a bigger spark than the EIs, no battery needed, I was running a battery eliminator to run my lights when I needed to mostly for brake light, I now run a very small battery to have a brighter rear light and brighter head light if I even need it, it starts first kick every time with out failure, yes mine hangs off the side but I really don't care as I have no intention of going down, but I have 2 x on the JH side and only damage was the first time a car turned in front of me and I laid the bike down, sheared off the plug leads in the front cover of the JH, a mate had a spare cover and bought a new cover from JH, the second time down when the Norton spat me over the handle bars in a quick stop for another car and bike fell on the JH side, no damage except to myself, I run soft mounting bolts of the JH so if I did do a high speed slide down the road the JH bolts will break and the JH will leave the bike, they are a solid bit of kit and will survive just replace the bolts.
My Norton is built for lightness, handling, and high revving, it's a very quick bike the JH works great around town and the suburbs, great on the highways and even better in the tight twisties, no matter what revs or speed I do crack it open and the bike just goes without any hesitation at all from low revs to flat out revs, as I have always said no need to retard it to fire the Norton up on first kick every time.
I don't care what most think about the JH hanging off the side, it works for me, I love it hanging in the cool breeze, its simple to work on if you need to, it's very reliable, produces a big fat spark, easy to start and I recon it looks great where it is and if you do go down hard on the JH side you are going to do more damage to your bike and the JH will survive with a few scrapes maybe.
Joe Hunt maggies won me over a very long time ago, set up right they produce one of the best sparks ever, the faster they spin the bigger the spark and the bigger the bang and I will say no more.

Ashley

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jseng1 said:

You


You need a 7/16" crow's foot wrench to loosen the mag nuts. Start with 1/4" nuts then drill and rethread them to fit the studs on the timing case. The 5/16" nuts are too big and a problem when wrenching.

Timing light is not always steady with a magneto - too much loose energy flying around.

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Alan L said:

Obviously the quality and the exact timing of the ignition spark is essential to maximise performance.

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ashman said:

I have owned my Norton since new, started with points system then first EI a Lucas Rita system lasted 11 month before it crapped itself, lucky not far from home, then replaced it with a Boyar was good till the big fire of 82 bike was off the road for rewire and waiting for the seat to be rebuilt one week later 100 miles from home the Boyar crapped itself, replaced it with another Boyar that was in the bike for over 30 years without any problems except a few battery failures, I have a JH on my 81 Triumph and its was so good, 9 years with 250K km on it with that JH only doing general maintenance, and to now the new 4 rare earth JH on the Norton with over 35k mile on it with out touching it except for taking the front cover off to check on the point and few drops of oil on the points cam felt pads.
My conclusion is the last boyar was good not problems with it except a few batteries letting me down, the boyar was still going when I replaced it with the JH, my Norton is my hotrod bike, built for lightness in the Featherbed frame, worked motor, the JH puts out a bigger spark than the EIs, no battery needed, I was running a battery eliminator to run my lights when I needed to mostly for brake light, I now run a very small battery to have a brighter rear light and brighter head light if I even need it, it starts first kick every time with out failure, yes mine hangs off the side but I really don't care as I have no intention of going down, but I have 2 x on the JH side and only damage was the first time a car turned in front of me and I laid the bike down, sheared off the plug leads in the front cover of the JH, a mate had a spare cover and bought a new cover from JH, the second time down when the Norton spat me over the handle bars in a quick stop for another car and bike fell on the JH side, no damage except to myself, I run soft mounting bolts of the JH so if I did do a high speed slide down the road the JH bolts will break and the JH will leave the bike, they are a solid bit of kit and will survive just replace the bolts.
My Norton is built for lightness, handling, and high revving, it's a very quick bike the JH works great around town and the suburbs, great on the highways and even better in the tight twisties, no matter what revs or speed I do crack it open and the bike just goes without any hesitation at all from low revs to flat out revs, as I have always said no need to retard it to fire the Norton up on first kick every time.
I don't care what most think about the JH hanging off the side, it works for me, I love it hanging in the cool breeze, its simple to work on if you need to, it's very reliable, produces a big fat spark, easy to start and I recon it looks great where it is and if you do go down hard on the JH side you are going to do more damage to your bike and the JH will survive with a few scrapes maybe.
Joe Hunt maggies won me over a very long time ago, set up right they produce one of the best sparks ever, the faster they spin the bigger the spark and the bigger the bang and I will say no more.
Don't compare Joe Hunt maggies to any other maggies, for simplicity the JHs are up there with the best, JH/Morris mags are very similar in design the Morris has a lock key cover, but I don't leave my Norton anywhere where it will get stolen, a hidden kill switch is what I use.

Ashley

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Schwany said:

Are you still thinking about hanging the JH ignition lump off the side? (Insert barf emoji here)

Too bad somebody is not making a really small alternator. TriSpark with a wallet sized LiFePO4 battery, a silicon reg/rect, and a good epoxy filled dual coil would do the job if a small light weight alternator was available. All kind of obvious, but anything would be better than hanging a magneto off the side of a track bike. To me anyway.

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Alan L said:

Hi all,
Excuse me if this appears slightly off topic but I have to confess that a lifetime of aviation has given me a pathological hatred of magnetos. For those who don’t know, piston engine aircraft usually run twin ignition systems with two magnetos. The extra efficiency of running twin ignition systems is very obvious with a profound rpm loss and rough running if only one magneto is selected. Of course the engine is designed to rely on two plugs firing so I guess this is not surprising.
The two big names in magnetos are Bendix and Slick. They are fixed timing, physically huge, weigh around 2kg each and rely on points. They are primitive to the point where I’m sure a mechanic in the Royal Flying Corp during WW1 would feel totally at home with them. One or both are fitted with an impulse coupling to provide a hot retarded spark for starting. Interestingly, the plugs have small gaps around 020” which to me would indicate the mags don’t produce a particularly high voltage.
They are totally independent from each other and the aircraft’s electrical system. Their great claim to fame is their supposed reliability, a feature that I have not found to be particularly evident. Depending on brand they have to be fully rebuilt or discarded and replaced every 500hrs.
In the last 30 years or so various attempts have been made to produce electronic magnetos that usually include an advance mechanism controlled by RPM and manifold pressure, as well as retardation for starting. In short, once the percentage power of the engine is below about 70% of maximum, it advances the spark beyond the static 28’ to around 35’.
Most brands have fallen by the wayside. The most recent iteration is called SureFly. I have recently installed one of these. It is not a stand ‘alone unit’ as it relies on the aircraft’s electrical system to power it, therefore only one can be fitted (the second mag is of conventional design) to ensure the engine keeps running in case of an electrical failure. It strikes me as decidedly odd that you can have two magnetos on an engine actually firing at different times on the compression stroke, yet it obviously works. I have to presume that the SureFly must be doing most of the work, as at reduced power settings it is firing before the conventional mag.
It’s great claim to fame, apart from unlimited life is that instead of a single spark, it provides a whole string of sparks over a number of degrees when it fires. There is no question that it adds to the engine’s power and efficiency with improvements of 2 or 3 lt per hour in fuel consumption (Lycoming 360 cubic inch, 180hp). Carburettored engines can be run lean of peak (not really practical with standard magnetos). At higher altitudes, where the engine is running at full throttle, improvements in speed of up to 5kts are possible. A slight disadvantage is higher cylinder head temperatures as a result of the extra power being developed. It is therefore mandatory to have individual temperature probes on each cylinder to ensure that CHTs stay within limits. It should be pointed out that these a genuine and verifiable improvements, not subjective ‘well it feels quicker’ we hear so often when discuss ‘hot up‘ bits we stick on our bikes.
The crux of what I’m saying is this, for over a century we have been lugging around massive magnetos that have not been particularly reliable nor objectively providing the hottest, best spark, yet we put up with it. Being aircraft, change is always glacial and certifying new parts incredibly difficult but nevertheless better parts were available. How a Joe Hunt magneto could possibly out-perform electronic ignition to a degree where it is worth having the lump strapped to the side of a bike is beyond me. To me it seems like stepping back a century.
So, after that long ramble about aircraft, how does this apply to our motorcycles? Obviously the quality and the exact timing of the ignition spark is essential to maximise performance. To my knowledge Trispark was the company that recognised the need to really fine tune our ignition system. For nearly four decades I have used a Boyer and Rita on my bikes but it might be time to upgrade to something more high tech. It is difficult to see that the 4 volt coils and wasted spark could possibly be the best option today.
Regards
Alan

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Schwany said:

Have you ever considered putting this wisdom in a Word file so you don't have to re-type it every few days. lol Just ribbing you. I know they work hanging out there.

That image you posted of the chopped Black Triumph reminded me of the late 1960's. Always liked the look of a chopped Triumph back then. Very clean example.

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Alan L said:

Hi all,
Excuse me if this appears slightly off topic but I have to confess that a lifetime of aviation has given me a pathological hatred of magnetos. For those who don’t know, piston engine aircraft usually run twin ignition systems with two magnetos. The extra efficiency of running twin ignition systems is very obvious with a profound rpm loss and rough running if only one magneto is selected. Of course the engine is designed to rely on two plugs firing so I guess this is not surprising.
The two big names in magnetos are Bendix and Slick. They are fixed timing, physically huge, weigh around 2kg each and rely on points. They are primitive to the point where I’m sure a mechanic in the Royal Flying Corp during WW1 would feel totally at home with them. One or both are fitted with an impulse coupling to provide a hot retarded spark for starting. Interestingly, the plugs have small gaps around 020” which to me would indicate the mags don’t produce a particularly high voltage.
They are totally independent from each other and the aircraft’s electrical system. Their great claim to fame is their supposed reliability, a feature that I have not found to be particularly evident. Depending on brand they have to be fully rebuilt or discarded and replaced every 500hrs.
In the last 30 years or so various attempts have been made to produce electronic magnetos that usually include an advance mechanism controlled by RPM and manifold pressure, as well as retardation for starting. In short, once the percentage power of the engine is below about 70% of maximum, it advances the spark beyond the static 28’ to around 35’.
Most brands have fallen by the wayside. The most recent iteration is called SureFly. I have recently installed one of these. It is not a stand ‘alone unit’ as it relies on the aircraft’s electrical system to power it, therefore only one can be fitted (the second mag is of conventional design) to ensure the engine keeps running in case of an electrical failure. It strikes me as decidedly odd that you can have two magnetos on an engine actually firing at different times on the compression stroke, yet it obviously works. I have to presume that the SureFly must be doing most of the work, as at reduced power settings it is firing before the conventional mag.
It’s great claim to fame, apart from unlimited life is that instead of a single spark, it provides a whole string of sparks over a number of degrees when it fires. There is no question that it adds to the engine’s power and efficiency with improvements of 2 or 3 lt per hour in fuel consumption (Lycoming 360 cubic inch, 180hp). Carburettored engines can be run lean of peak (not really practical with standard magnetos). At higher altitudes, where the engine is running at full throttle, improvements in speed of up to 5kts are possible. A slight disadvantage is higher cylinder head temperatures as a result of the extra power being developed. It is therefore mandatory to have individual temperature probes on each cylinder to ensure that CHTs stay within limits. It should be pointed out that these a genuine and verifiable improvements, not subjective ‘well it feels quicker’ we hear so often when discuss ‘hot up‘ bits we stick on our bikes.
The crux of what I’m saying is this, for over a century we have been lugging around massive magnetos that have not been particularly reliable nor objectively providing the hottest, best spark, yet we put up with it. Being aircraft, change is always glacial and certifying new parts incredibly difficult but nevertheless better parts were available. How a Joe Hunt magneto could possibly out-perform electronic ignition to a degree where it is worth having the lump strapped to the side of a bike is beyond me. To me it seems like stepping back a century.
So, after that long ramble about aircraft, how does this apply to our motorcycles? Obviously the quality and the exact timing of the ignition spark is essential to maximise performance. To my knowledge Trispark was the company that recognised the need to really fine tune our ignition system. For nearly four decades I have used a Boyer and Rita on my bikes but it might be time to upgrade to something more high tech. It is difficult to see that the 4 volt coils and wasted spark could possibly be the best option today.
Regards
Alan

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worntorn said:

I like the self generating aspect of magnetos.
As far as keeping things light, tough to beat EI and a small battery.
To cover the worry of ignition failure on the road, carry a spare ignition.
5.9 ounces!
View attachment 100729View attachment 100730

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Fast Eddie said:

On a road bike yes. The battery is little more than a capacitor in that situation.

Can anyone tell me how big the battery would have to be, including keeping a healthy safety margin, for a track bike sans generator?

Assume a max of 12 x 20 min sessions in a weekend (that’s 240 track minutes, which is very different to 240 road minutes, the bike will perhaps be doing 10-12 mpg for example) plus warming up, being in the waiting area, etc.

Calculations would have to be based on using very high output coils, Dyna or Crane etc.

This is a genuine question BTW…

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cash said:

Wouldn't there be a reduction in friction when using an EI over a mag?

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Fast Eddie said:

On a road bike yes. The battery is little more than a capacitor in that situation.

Can anyone tell me how big the battery would have to be, including keeping a healthy safety margin, for a track bike sans generator?

Assume a max of 12 x 20 min sessions in a weekend (that’s 240 track minutes, which is very different to 240 road minutes, the bike will perhaps be doing 10-12 mpg for example) plus warming up, being in the waiting area, etc.

Calculations would have to be based on using very high output coils, Dyna or Crane etc.

This is a genuine question BTW…

Click to expand...