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Last year I answered a question on one of the Indian boards about a 101 that had been converted to 12V. It had a Dyna S single fire ignition and was drawing all of the generator output for the ignition, which didn't allow slow riding or headlight use. The question was from Jerry Hatfield, who had just had his Scout rebuilt as a 52 incher with electronic ignition by Butch Baer and converted to 12V. I assumed that this large of a current draw would either be caused by a shorted control unit, which would preclude starting or incorrect primary resistance in the coils. Jerry wrote back and asked if I would work on the bike, though I tried to get him to let me talk him through the repair. I had just pushed my old shop down and started building a new one just before the Cierro Grande fire started last year. |
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Jerry's 101, with seat wrapped to protect it - from me! |
| This, combined with an unusually heavy snow season last winter, caused my shop to be just a pad with a few poles sticking up. Jerry talked me into working on it anyway sometime in January or February. So I borrowed a corner of a shop in a nearby town and got to work. After a coupla hundred emails Jerry met Michael Breeding and me in Santa Fe for dinner with Show and Tell (check out the past Blueprint Project for an overview of Jerry's next project). After dinner we took his bike to Espanola and unloaded it and I got my first look at it. Butch's machine work was spectacular. The Dyna looked like it belonged there and the machining and welding to allow drysump oiling was way above first class. | 
What's Jerry up to? (click photo and find out) |
| The next morning we hooked up the battery and promptly let out all the smoke! (electrical theory fans take note all that stuff they taught about electrons and EMF was wrong - electricity is really just smoke running through wires; let the smoke out and it doesn't work) The reason it had quit running was that the voltage regulator was completely melted. I disconnected the regulator, but we had seen the last gasp from the battery which wouldn't even consider taking a charge and obviously had damaged plates. I did a quick check of the primary resistance. The coils showed 2.7 ohms primary resistance which sounded very low. A little simple math, amps = v/r, gives 4.4 amps per coil or 8.8 amps total draw (I know that it isn't constant but close enough) which agreed with the complaint. The old Chief generator that was on this bike was rated at 10 amps after conversion to 12V and the regulator was a Bosch unit. I then retired to the house to do a little research and Jerry headed for Texas. | 
Dyna S single fire ignition unit |
| A little
research revealed that the Dyna S was supposed to have a primary resistance
of no less than 3 ohms for racing and 5 ohms for street use. So I started
looking for coils that were advertised as compatible with the Dyna S. At
this point, my main concern turned from function to form. Every coil I
found looked ugly compared to the Yamaha coils that were on it. Their mounting
bracket looked right at home on the 101, so I decided to correct their
primary resistance with a external resistor and see if they were damaged.
I addressed the regulator first, since the Bosch regulator that was on it was a B circuit 12V regulator. The battery was small, so I decided to go with my longtime favorite Bosch regulator for a no-battery Sportster. It is a favorite because of its robust design and quick response. However I had cleverly lost the Bosch number for this unit. In my world, buying at a fancy motorcycle boutique is out of the question. So, being the clever guy I am, I used my wits and begged at the Flathead Power Tech Talk board till Hooter gave me a number that would work at JP Cycle. Not as cheap as having the Bosch number (0 190 215 039 740) but better than the boutique. |
The Flathead Power "Tech Talk" board has an Indian section in addition to H-D Flatheads & Knuckleheads. Well worth a visit! |
| I installed
the regulator and polarized the generator, then jumpered a 2 ohm Chrysler
ignition resistor between the coils and the ignition switch. (Stole a battery
from another project.) On the first kick I was rewarded with a running
engine and some positive amperage on the gauge. A quick check with the
Fluke showed that the regulator was set at 12V which would be correct for
no-battery but would never charge a battery which requires 13.2V minimum.
Since the battery was small and in a hot location I adjusted the regulator
to 13.5V, but there still wasn't enough spare amperage for the lights but
real close. At this point at least it didn't require half-throttle to break
even.
I went searching for a 3 ohm resistor, but nothing that would suit the 101 seemed available. After a bit of searching, I found that NAPA offered a 5 ohm resistor that looked like a ignition resistor externally. I then started soldering the turns of resistor wire together to reduce the resistance (clever, huh?). After each coil I shorted I tried to start it and when I finally found a resistance that would run I broke out the oscilloscope and checked the secondary voltage. Then I shorted more turns until it would put out 30KV into an open circuit. The resistor ended up at 2.7 Ohms. The three ohms I wanted dropped the voltage too low for there to be any advantage over points except the lack of maintenance. Then I fabbed a bracket for it and bolted it on. |
Yahama coil with resistor bracket-mounted on top
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| A quick
test ride (15 miles) confirmed that I was on the right track. Any reasonable
road speed produced a charge then the charge dropped back to zero just
like it should. Then I tried a larger generator pulley that Jerry wanted
to try but decided that it needed the 2" pulley. We then decided to replace
the broken headlight switch with a double post double throw switch that
followed me home off a fire truck. I fabbed a cover plate and mounted the
switch. Not quite original but it works every time.
It ran and charged good so I rode it the almost 20 miles to my house and told Jerry to come and get it. He wanted to go for a ride in the mountains (we have lots of these) so we picked a date. The week he was supposed to come up I rode it to dinner down the road and on the way back it died like the switch was turned off and wouldn't start. So I pulled the plugs (very hard to kick) and checked the spark. Looked great - nice blue spark - so I pushed it home and went into desperation mode. Cleaned some rust out of the carb - rechecked the spark - kicked till I could bearly walk etc. etc. So I wrote Jerry and canceled. Needed time to think. The next weekend I brought the Fluke home and rechecked everything - primary voltage, fuel, watched the plugs fire again - nothing but the occasional single pop. So I hooked the scope up to view the primary wave form and kicked it over with the plugs in. AHA! The primary voltage fell to about 2V every time the bike shook. I could turn the battery off by hitting it with my hand. Another battery and all was right with the world... Or at least with my world. |
Not a circuit diagram - it's the route we took for a weekend's test-riding
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| Jerry
showed up with his Four so we could ride over the weekend before he took
the Scout home. Since Jerry's doing a book on Rollie Free, Michael brought
his Vincent Black Shadow.
After a leisurely breakfast up the road we rode to all the mountain villages where the pavement stops, trading bikes several times. The Shadow was a real surprise. All the old road tests I had ever seen berated the handling and brakes, but this bike handled great and the brakes were above average for its age. It actually reminded me of a Guzzi Lemans (with stage three engine) I once owned. Unfortunately Arthur (Mr. Arthur Ritus) reminded me why I sold the Guzzi (that had nearly the same riding position). |
Michael's Vincent, which he brought along in honor of Rollie Free, legendary Indian and Vincent racer |
| The four was a pleasure and very easy to ride... Until I reached down to grab the shifter and downshift as we climbed a mountain behind a very slow truck pulling a hay bailer. Unfortunately I also grabbed the plug wire, which let me know of it's existence a coupla hundred times. A four will continue to climb a mountain (and shock the hell out of you) on three cylinders. My favorite was the Scout but I am a little biased. The next morning Michael couldn't make it, so we rode to Sebidia which we had missed the day before. Everything was working so good that I decided to ride over to the dirt road down the Rio Grande Gorge, but after looking at it we decided that the Scouts brakes weren't up to it (external contracting rear). | 
Jerry's "Bubeck Replica" Four, with Vard telescopic forks |
| We decided to ride up the dirt road to the high bridge and into Taos for lunch. After five miles of trying to keep up with Jerry on the four I totally understood why the Vard fork was a favorite (Jerry contributed a "ride impression" of the Vard fork to the VI List - you can find it reprinted in Indian Choppers Corner Part 5). About halfway through Taos I noticed that Jerry wasn't back there so I waited a while and then went back to look. He was on the roadside with a flat, but at least it was right across from a restaurant. After lunch we tried to find something to fix it with (fix a flat etc) to see if we could limp it home. No luck. So I rode back to get the pickup. The afternoon showers fired up on the way back and it rained on me three times and hailed once before I got home. But despite all that, it was a great weekend. Even if it did end in four-wheels instead of two. | 
Ojo landscape |
