Vincents were originally 6V positive ground. It's recommended on machines coming out of long term storage to confirm the exact polarity. As generators ordinarily need servicing, now is the time to convert to negative ground. Though magneto ignition obviates total reliance on one, modern traffic conditions necessitate some sort of Daytime Running Light in urban settings and thus the need for a nominal but reliable charging system. With the arrival of LED lighting and halogen retrofits, a stock Vincent charging system - especially with a Lucas E3L retrofit - is very adequate when a few small mod's are made. If servicing your generator now is the time to ensure your cam spindle plate is anchored securely to the top of the engine cases. With the generator removed, you will note a large recessed slotted screw (MOO3 - G334), check to ensure it is tight.
- Headlight: If you have a U.S. spec Series C Vincent, it will have a Miller split-band (very rare) 7 inch sealed beam as shown on the Red Rapide which was originally a U.S. (GE3044) sealed beam of high (4.5amp on low) draw and thus only a Lucas E3L/electronic regulator on a magneto equipped machine can be expected to cope in an urban setting. But, with the standard 3 alignment eared mount land, there are many non-original modern alternatives available through the classic car industry. I'd recommend a 6 volt halogen with the lowest rated low beam available if you're running a Miller D6 generator, of a Lucas E3L, the more readily available 35W low beam will not tax your system.
If your machine is a late series B or non U.S. C, it will be equipped with the Miller bulb reflector setup. Standard was 24W/36W incandescent which is adequate for general use if the reflector in good form. A 6V halogen retrofit is available in the U.K. via the Vincent Owner's club magazine MPH but will tax a Miller D6 in urban riding. I have adapted a late model Wipac reflector as found on mid 60's British bikes to the Miller lense which provides more bulb optionsin the 24W low beam range.
- Headlight Switch: original (and quality reproduction) Miller switches have 4 positions - Off, CH, Hi, Lo - which offers a convenient option for those residing in motorcycle DRL (Daytime Running Light) states or desiring an added safety measure of running their machine with only the headlight on. Wiring your headlight circuit into the CH terminal provides headlight only operation in this mode while preserving the functions of the Hi Lo positions...just be certain to turn it off on magneto wired machines as this circuit is live with engine off.
As a measure of how far voltage regulation has come since Vincents were in production, that CH position on your light switch? That stands for Charge, selecting this position enabled one to manually provide battery voltage directly to the field coils of the generator to ensure maximum output.
- Tail Light: The original tail light is entirely inadequate, no improved incandescent/halogen bulb arrangement can be made to work, the stock housing is too small to dissipate the heat. Though made in the U.S. by bulbsthatlast4ever, it is currently available only through the Vincent Owner's Club Spares Scheme. This unit is a drop in requiring only you solder two tiny leads to each of the copper tabs. It pulls a fraction of the amps of the original and is far brighter.
- Electronic Regulator: Bob Kizer’s superb electronic regulator, the PODtronic, is an easy retrofit in the original Miller case. Be sure to get his alloy bracket for mounting unit on its side in the case and save yourself a few minutes fabricating one. You’ll need to flash your field coil occasionally if your machine sits extended of time because, even though extremely efficient when operating, it does require .75 volts to excite initially compared to as little as .25 - .50 on mechanical regulators.With an electronic regulator, you are in a position to take advantage of modern superior battery technology, see Battery below. Wheras 6V mechanical regulators cut out a 6.6 to 6.75V, PODtronics limit at 7.25 which befits modern sealed battery technology. As AGM batteries have a standby rate of 6.8V as opposed to lead acids, as available for a Vincent currently, can be as little as 6.2V so you will benefit with brighter lights in general. Wiring is simple: red is regulator output and routed to your ammeter, yellow is to the armature brush, green to one end of your field coil wire and black is ground to the generator case.
- Generator (Lucas E3L): Though not original to pre D machines like the Miller, Lucas E3L’s are close in appearance and, despite their maker’s dysmal reliability record, very robust,reliable and long lived. Replace the non-sealed bearing - at a minimum - on the brush plate end as it is impossible to completely seal with the felt distance piece provided and results in a buildup of brush effluence which may cause the commutator gaps to fill and result in your commutator glazing over. If your brushes original, note the spring rates if planning to change them, some reproduction springs far to strong resulting in rapide brush wear. It is more important you have full brush contact with the commutator than high spring tension, radius them carefully.
If performing the simple conversion to your generator to enable using a PODtronic,
it is advisable to "motor" your generator to confirm you've got the polarity
right for correct rotation and to flash your field coils. In the process of setting up your generator to run most electronic regulators you will have one end of your field coil exiting the generator housing, the other will be attached to the armature brush. To motor, attach that field coil wire to the generator housing and then the negative side of the battery (neg ground system) and the armature wire to the battery positive. The generator should turn over smoothly at about 100rpm or so with no notchiness. If run hot, Lucas generators are prone to slinging the copper segments loose which in turn will short against one another. If you have a generator acting oddly and the brushes are worn at an angle even though their carriers perpendicular to the commutator, that is a sign the segments have parted and are centrifuging outward at higher engine rpm. Doug Wood can provide a rebuilt replacement on your core.
- Miller Generators 02/09 Update: A good Miller D6 as originally fitted wired in series to a PODtronics electronic regulator running a 24/36W headlight, LED tailight and two speedo bulbs is perfectly capable of keeping your battery charged in city/urban riding. For extra insurance, replace your original rubber case 8amp lead acid battery with a replica battery case and install a PowerSonic AGM battery for extra reserve.
- Battery: With the arrival of 6V LED lighting and if retaining a magneto ignition, for average use, a 6 volt (converted to negative ground) electrical system is very adequate. Currently, there is only one traditional reproduction lead acid battery on the market suitable to the specific size required for a Vincent. Besides prone to leakage at the terminal posts from poor construction, you run the risk of venting for which the Burmabrite alloy fenders are susceptible to corrosion. Fitting an electronic regulator enable use of an AGM (Absorbed Glass Matt) battery (I do not recommend use of an AGM/jell battery with a mechanical regulator). Here is a reproduction Exide rubber battery case hollowed out to take a Werker 12AH 6V battery stood on end, available at BatteriesPlus. The most challenging clearance issue is battery length (now height, as stood on end). Using a 1 inch hole saw, you will need to completely clean the battery case floor flat, eliminating the ribs. As spade connectors are not adequate as the primary anchoring point for your harness in this application, make up brackets anchored to the old lid to which your harness can be affixed as illustrated here.
Caution: AGM batteries have rather specific charging protocols compared with standard LA batteries, specifically where initially being brought into service as well as topping off and maintaining on standby. It is highly recommended you purchase a quality battery charger like the Battery Tender Plus by Deltron rather than "make do" with trickle chargers. A digitally controlled 3 step charging algorithm avoids overcharging thus potentially doubling service life on these batteries when maintained in this manner.
A few notes on batteries and the benefits of using AGM's. A fully charged 2 volt cell (of which there are 3 in a 6V battery) is 2.15V which times 3 cells equals 6.45V fully charged. A cell is considered fully discharged at 1.9V (5.70V total) meaning there's only .25V per cell or .74V total between full charge and discharge. Likely traceable to production shortcomings, available replica LA 6V batteries for Vincents and other vintage machines vary widely in their final standby voltage after being charged and put into services, often it may be as little as 6.25-30V at a lower AH rate than originally specified which only narrows your duty cycle range. Powersonic AGM batteries will not only tolerate routine charge levels of 7.25V (the cutout specified on most electronic regulators) but standby voltage routinely rests at over 6.55V providing you with extra margin and higher charge density yield a greater AH rate.
Note, your battery acts as a capacitor for your electrical system and in that role works in concert with your regulator to buffer voltage spikes. To avoid excessive duty cycling of your regulator/generator a general rule of thumb is not to fit a battery rated at less AH than your generator's rated average output. The capacity of single AGM batteries/battery packs which can be fitted within hollowed out Exide-type rubber case batteries are as of 2010 limited to 12AH @ 6V and 7.2-7.5AH @ 12V. These capacities are adequate for Miller D6 and Lucas E3L generators but not advisable the Alton A.C. generator. John Healey sells a soft rubber case reproduction of the Exide which is slightly taller in which you may manage to squeeze batteries of larger capacity but as it has clearance issues with the underside of the rear spring boxes on both my machines, I've not fitted one/able to specify battery specs for it.
- Wiring Harness: The pre-D Vincent wiring harness is very basic. Unless your newly purchased machine arrived running and all systems operational, it is advisable to replace it with one of your own making or the superb reproduction offered by John Healey. The original harnesses did not provide a dedicated ground to the largest energy consumer - the headlight - instead, relying on the headlight bucket achieving ground through the mounting brackets, FF3/FF4 to the headstock and then UFM where the battery ground wire is connected.. 6V requires double the amperage for the same load as 12V and many rewiring/patches have been done with inadequate gauge wire. At a minimum, you want a heavy run from your generator to the ammeter, then switch and to the headlight along with a dedicated ground back to the battery ground which should be anchored to a small screw at the left side rearward end of your UFM under the fuel tank.
- Fuses: Vincents did not have any fuses fitted originally but it is advisable to install one as you have several locations at risk of shorting, the horn circuit for which the wires are constantly live and the brake/tail light wires which run inside the lifting handle and can potentially break around the fender flap pivot. For a magneto equipped 6V system, though 10A entirely adequate, to reduce heat from such small circuit gauge, a 15A is better and is the recommended capacity for a PODtronic regulator. As seen in the Electronic Regulator section above, mine is installed in the battery ground circuit just aft of the UFM attachment point where it can be conveniently pulled when the machine is stored.