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VW generator conversion for Chief: Let there be light!

Moderators: Curt!, Pa

Posts: 41
Location: Lakewood, Washington USA
With near 1000 miles on the ’46 Chief engine break-in I’ve come to realize that the “high output” generator with regulator isn’t putting out much more than my ’39 Chief generator with cut-out. I have a pair of driving lights which I can’t use or I’ll drain the battery. The only other extra electrical load on the ’46 Chief is a pair of rear marker lights. I figure total draw is about 20 amps and the generator is lucky to be putting out 15-18 amps. I remember hearing about a VW generator conversion which would double the output and so did a search and found very little to go on. I was able to obtain a VW generator and matching regulator rated at 7 volts, 45 amps, negative ground which I figured would do the trick. Cost: $20.00.

The VW generator’s dimensions were almost exactly the same as the Indian Autolite generator. The only real difference was the VW generator being slightly smaller in diameter (about 1/32nd”) but I knew it would fit into the generator holder even if I had to use a shim to make up the difference.

The main problem was going to be rotation of the armature for although both the Indian and VW generator show a clockwise rotation, you have to mount the VW generator “backwards” for it to fit in the Chief’s frame. Thus, the back end of the VW generator (normally with a large cooling fan attached and mounted inside the VW engine shroud) on which you have to mount the generator pulley would be rotating counterclockwise. I checked both generators by “motoring them” (attach positive lead to hot side of field, attach other field lead to armature lead and attach negative lead to generator body). Both motored in the opposite direction to their intended generating direction and in opposite directions to each other.

Since the flow of current in the field determines polarity, I figured that swapping the two ends of the field as they connect to the regulator would generate the right polarity with the VW running opposite its intended rotation. In essence this ran current backwards through the field to compensate for the armature running backwards in the generator. I had to solder on small wire extensions to the field leads so they could reach across to the other leads position on the regulator. I put it together and motored it again and….Bingo….it rotated just like the Chief generator.

Then it was just a matter of pulling out the armature, chucking it into my lathe and cutting the pulley shaft down to the same diameter as the Chief pulley. I also had to file down the key and slightly file open the key slot in the pulley so they would mate snugly. I then cut off the other end of the armature shaft…the end that would have normally been used on the VW for the generator pulley. I mounted the VW generator with the regulator pointing downwards: there isn’t sufficient room to mount it upright. I also had to insert a thin piece of brass shim (.015") about 1” wide and 5” long between the generator body and mounting bracket to ensure a snug fit.

The results were absolutely great! The battery charges to 7 volts regardless of the load and even with all the lights on there is still a slight maintenance charge. If the battery is run down, say at a traffic light, the generator charges it right back up and then goes back into a maintenance charge. With full load, the generator will charge at about 30 mph in 3rd gear. When riding with less than a full load (i.e. driving lights off) it will do even better. Even with all lights off, the current is regulated so you don’t have to worry about boiling off your battery.

I know it may seem sacrilege to use a VW generator on and Chief but I ride my bikes year round and performance and reliability are key. It also looks great too coming very close to the original Autolite in appearance! I guess I could have opted for a 12 volt upgrade to the Chief generator or even gone to an alternator. However, for $20.00 and a little bit of experimenting I have solved this common problem. I suspect that the Bosch electronics will be a lot more reliable as well. My biggest surprise was that Bosch was able to pack that much power into such a small package. I have a ’39 Plymouth with a 35 amp generator that has to be twice that size! VW also makes a 30 amp generator but I’d stick with the 45 amps: lots of reserve power means you can use higher output bulbs.

Posts: 41
Location: Lakewood, Washington USA

Here's some photos of the VW generator conversion for my '46 Chief. I think it looks a lot more authentic than alternators or some modern replacements. I don't know that there is any great benefit changing over to 12 volts unless you are greatly increasing wattage. There may be some savings and flexibility in obtaining light bulbs but how often do your replace them? You can even get 6 volt halogen bulbs for vintage/antique cars and bikes. Essentially 6 volts can do anything 12 volts can do: it only takes twice as much.

Posts: 3010
Location: Central Illinois, USA

Without any doubt, a Bosch looks much, much more acceptible than an alternator or billet-finned-end conversion: That's why I have a Bosch regulator on my standard CE!

The only problem I ever had with Bosch generators was finding one.

Not only are they scarce here in central Illinois Bug boneyards, they are expensive (three times what you paid, last time I searched in the '90s).
And when I ordered one from an auto parts vendor, a double-ended van model showed up...dead in the box! (They took it back, but could not replace it..)

I believe Wilson Plank has worked up 12v conversions for the Bosch, and adapts them for Scouts as well. But frankly, as I posted on the concurrent thread in this forum, one could cut to the chase and get a real Autolite from in either voltage.

We both need fake endcovers that have the 'trefoil' bearing cover like an Autolite, to keep the dust out of the Bosch, if nothing else!


Posts: 41
Location: Lakewood, Washington USA
Hi Cotton:

The 12 volt VW generators are nearly 4" wide and will not fit into the Chief generator mount so they are out as an option. The 45 amp 6 volt generator I used is less available than the typical 30 amp 6 volt generators which at least here are pretty common and cheap....there are very few cars on the road today that they fit! I may try the same conversion on my 1939 Chief with a 30 amp VW generator just to see how well it works although the stock Autolite generator/cut-out set up currently works fine.

Posts: 6
Here in Northern Europe we have been using a 12volt bosch generator type for years.

The generators were installed in Opel, Saab V4 and probably a few more cars.
The generator body have to be turned down a few millimeters. New cast autolite lookalike endmounts are available in Sweden.
Also some have made an endcover from plastic/lexan for hiding the stock endcover.

While the bosch generator have worked most of the time over the 60000++ kilometers I've ridden since 2002, there are some issues.

1. The 12volt generators needs to much (if you actually ride the bike everywhere..including in the city) rpm to start charging.

- I've tried using a toothed belt with altered ratio instead of the stock setup. This works if you select proper pulleys. You don't want to spin the generator too fast, and some of the pulleys are too soft.

- Currently I'm running 4 neodym magnets installed inside the generator. This works great, however there's still no charging at idle.. but in REAL-LIFE it works ok.

2. External regulators.. have cables flapping in the wind and I haven't found a proper regulator yet. Also I've had problems with the mounting brackets and shorting inside the housing.

- Electronic regulators. I've burnt out 2 regulators (from some kind of tractor). I bought my generator as a complete kit from Sweden, but have replaced almost everything. The regulator was installed inside an original regulator housing, and the field shorted out every now and then. The ceramic type fuse holder melted. Lot's of problems... have been running a mechanical regulator since last year.
In sweden they are using a modified regulator from an mid '90s Volkswagen alternator, which they say work "perfect". I gave up trying to get information on how to wire up this regulator..
Now I'm waiting for a BOSCH electronic regulator ( 30019) which was sold as a replacement for the old mechanical regulators. I hope this south America made regulator is of german quality and work on an old motorcycle. The best solution is probably to install a custom made regulator which one of the Norwegian riders make, and I hope mine will be ready soon. This regulator is adjustable and made especially for the indian's electrical system( current draw, vibrations, small battery etc...)

- Mechanical regulators... as long as they are in good shape, they usually work. However, my generator is rated at 25A max (300watts). But the Indian's electrical system is probably just burns 120watts (10 amperes) with a full battery. The bosch regulators are rated in amperes. I've tried a 15A regulator and a 25A. The 25A is too much, and when readjusting the voltage I found the regulator to cut out the field at just above 2000rpm. In the long run it burnt out the platina points in the regulator...or I believe that's what's happened. The 15A regulator didn't regulate the 25A that well, especially when the battery was full.. the headlight was flashing at higher revs .
For my sport scout I got a NOS 15A bosch generator with endmounted mechanical regulator. So far it looks like this works like a charm. The charging kicks in early, and it regulates the voltage really good! I will not upgrade this with an electronic regulator until the mechanical one fails..

If I find more of these generators I will buy and stock them, I've given a few away to other indian riders already...

Anyway.. if one want to ride lots of miles with these old machines... one will find that theory don't always reflect real-life.
I often hear about "quality parts".. is this a "visual museum quality" or do the parts actually survive thousands of miles of rough roads.
I got tired of spending time and lot's of money (add 60-80% in shipping/ taxes ) on replacing "quality" parts all the time. Now I only trust myself and the few dealers/ riders that actually (ab)use the parts/ bikes they build. Bikes for actual riding requires a totally different parts quality than bikes that only see a few miles (mostly on a trailor).
Sometimes the "riding quality" parts are more expensive, but it's worth it in the long run.

About everything is wrong with the eastern europe brakeplate I got this winter.... really shitty quality...
However, I'm amazed how the Kiwi supplied chain adjustor have held up to the bad machining on the brake plate. The adjustor is now quite bent due the mis-machined brakeplate, but it hasn't broken after almost 4000 miles of abuse and long days of riding. That's the kind of quality I want and need if I'm going to continue riding my bikes everywhere.

Me at the North cape (71 degrees north) some weeks back..
3200 miles trip back and forth( on twisty bumpy roads with <40mph average speed) on a 9,5 day trip..including a vintage motorcycle meeting in the weekend.
Yes...I had problems with the mechanical voltage regulator on this trip.... wanted o install an alternator after that trip...


Posts: 3010
Location: Central Illinois, USA

The South American (Argentine) Bosch regulators have served my customers well.

Identical units that arrived in Accel boxes were dead upon arrival.

I have no explanation, other than many Accel products that I have dealt with were below expectations.


Posts: 604
Location: Largo, Fl

If ya'll want a charging system that you can get at the junkyard for $15 (or even from a DUMPSTER) and NEVER have to touch your charging system again just go Toyota! The ways to mount them are whatever you come up with. Here are 2 examples and I could show you at least 3 more ways that are Slightly different from these! Simple and BULLETPROOF!!

Posts: 77
Location: Espoo, Finland

"Now I'm waiting for a BOSCH electronic regulator ( 30019) which was sold as a replacement for the old mechanical regulators."

Where are you getting this?? Company I work for is a distributor for Bosch, but I couldn't find this.

Do you have a Bosch part# for this unit??


Posts: 6

Had a BBQ with 8 of the English Indian club guys tonight. They are on their way home from Finland.
Several bad things happened on the way home from the Indian rally, 2 crashes and 1 indian burned up..

I couldn't find the regulator either, using direct lookup to the importer..

I read that the regulator is going out of production, but the vintage VW beetle stores seems to list them.
Most of them buy direct from Mexico I guess.

Here are the bosch # 9 190 040 099E
There are some on ebay, I found one in Germany.
I would guess the vintage VW dealer nearby have them... but it's probably 2-3 times more expensive than ebay..

Posts: 77
Location: Espoo, Finland

Ok, have to try Ebay then...That's what I suspected.


Posts: 6
Still waiting for mine to show up from Germany...and I'm leaving for the Nordic Indian rally tomorrow..
I have a backup mechanical regulator to install in case it doesn't show up in time.

Been working on the sport scout the last few evenings/ nights, and it should be ready for the 750 kilometer ride this weekend.
A friend will be riding the sport scout, it's easier to handle for a near first time indian rider.
I had to tighten the generator sprocket on this bike, but it shouldn't move now.
If I start the bike when warm with lights and everything on, the generator lights stays on for like 25 seconds.
At idle the generator charges:) If I can find another one, I may put one on the chief.. the 15Ampere generators seems to work better than the 25A:)

Posts: 1002
Location: Ojo Caliente,NM,USA
If you can find it the Bosh 0 190 215 039 740 it is a very robust unit designed for motorcycle use.It has a much faster responce time and is very vibration tolerant. The only drawback is that it must be adjusted as it comes set around 12v for no battery use so you must adjust it to between 13.2v and 15.2v depending on your needs.

Posts: 51
here comes a bunch of BOSCH 6 Volt generators together with a new BOSCH regulator. They all will fit on the old Autolite bracket, as the guy says. He will ship worldwide.


Posts: 6
Hello again!

I finally got the regulator last night.
Had to pay almost $20 in "tax handling", in addition to the taxes!!

Anyway, the regulator seems to work fine! The ampmeter don't jump like when running the mechanical regulator.

However, the regulator housing was larger and more bulky than expected.
For now I have the regulator mounted under the seat, between the upper rearframe tubes.
That should work for the rest of this season. Rode the chief to work today, just to check that the charging works ok.

Went on a ride this weekend also..added a youtube video : ... ture=email

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