[brucewr0@gmail.com]

advice needed to change from 6v pos earth to 12v neg earth on my feb 1980 350 bullet. i have a boyerbransden 12v 00064 electronic ignition and am ok with that as instructions included. also have a i presume a 12v alternator and stator 3 wire  but have to make the bike 12v neg earth. there is already a KBPC 6/12v regulator fitted. besides the obvious bulb changes i know i need a battery/coil but beyond that i run out of knowledge. can anyone help with instructions.  thank you

[AzCal Retred]

Hitchcock's in their on-line parts book says the 1980 machine has a 6V alternator. The good news is that there is nowhere to go but up.
https://www.hitchcocksmotorcycles.com/partsbook-pages/9259

I have no idea what a KBPC 6/12v regulator is or its operating capacity.

The smart money is to get the Lucas rotor. stator & regulator. This gives you 120 watts of output and matched components. Your system gets a clean start & double the wattage output of the OEM 12V/60W system.
https://accessories.hitchcocksmotorcycles.com/accessory-shop/High-Output-Alternator/15594
https://accessories.hitchcocksmotorcycles.com/accessory-shop/Charging/15429
https://accessories.hitchcocksmotorcycles.com/accessory-shop/Powerbox-cat/37670

The question I have is why are we installing an electronic ignition? Points work great on these low compression, low output dinosaurs. The same stack of lash-filled timing gears drive the distributor so you aren't going to see any more accuracy. Performance won't change. If spark goes away on an electronic ignition you can't field repair it.

It'll be the best part of $300 USD to "upgrade" to 12V and pretty much all you'll have to show for it is maybe better lighting.

I would get a copy of the Snidal book, download the Hitchcock's online manual and learn to keep the old girl running as is until the existing 6V rotor, stator or reg/rec finally die a natural death. THEN I'd look into slapping on a 12V system. In the meanwhile you can accumulate at your leisure a modern, stock 12V rotor, stator, reg/rec & spark coil at the best deal you can find. And you'll still need a new 12V battery that fits your battery box.

[brucewr0@gmail.com]

thank you.
more thought and reading coming up.
regards

[stinkwheel]

I have limited experience on this but from my general knowledge about electric/electronics, the only thing on these bikes that really cares much about the polarity is the regulator/rectifier.

If you have a 3 wire alternator, I'd suggest getting a modern regulator/rectifier unit and hooking it up to the reg/rec in the conventional manner and attaching it to a 12v battery with the negative to the common earth and the positive to the fuse/switchgear. The alternator is putting out AC anyway, the rectifier will rectify it and output DC positive to the to the positive wire. I've even found that most standard japanese reg/rec units have bolt holes which line up exactly with the captive nuts on the folded flat steel frame brace under the seat. I have one off a ZX6R on my trials bike.

It's not uncommon for people to do a 6 to 12V conversion on other bikes by simply fitting a 12v voltage regulator and swapping the voltage sensitive componants like bulbs. The alternator is still outputting the same amount of power, just regulated at a higher voltage.

You'll need a 12V flasher relay, horn, bulbs and possibly ammeter. If you retain the points ignition, you'll ned a coil and condenser.

The wiring and switchgear is all fine because when you double the voltage for a given power output, you half the current so you are well over-spec in that respect.

The ammeter may well be ok, as mentioned, you'll be running half the amps. I'm not sure how it'll react to the higher voltage. You'd need to swap the wires over from one post to the other if you don't want it to swing the other way

[brucewr0@gmail.com]

thank you for that .
i inherited a 12v neg earth boysen electronic ignition and new alternator / stator in the box of bits came with the bike so after much research this morning i only have to purchase a solid state regulator/rectifier swap my bulbs battery etc.  there is a new alternator fitted so as you say i,ll see what it puts out when i get going. i have the extra new one as back up.
 no indicators so pretty simple.
only cost me the new reg/rec $90 as all bulbs/battery/coil had in the shed anyway.
regards

[AzCal Retred]

I like the idea of a practical reg/rec test. If the 6V stator makes about 20VAC open circuit when you rev it a bit you are probably there. The 12V stators hit about 30V, but you should just need (1.41 x 14) to hit top-up numbers. Worst case you already have a 12V reg/rec in the parts drawer.

You'll need to bootleg in a 12V battery for the test. Fused 10A jumpers & #16 wire or better from the 12V reg/rec to a handy car battery will get you by for a test. If it works, it'll be pushing 13.5 V or more back to the battery at 1500 RPM or so, THEN you have the guts of your new system for the price of a reg/rec. Good test for that KBPC 6/12v regulator!
Just put the stator AC to the 12V reg/rec and run the 12V battery jumpers to the test rig car battery. Let the 6V (+) ground battery run the ignition normally for the test.

There's no real difference between 6V & 12V for insulation purposes, wiring is usually rated 60V to 300V anyway, way beyond what it'll ever see. 12V Load currents will be 1/2 of their 6V counterparts.

The ammeter just knows current. IF the OEM 6V reg/rec puts out 60W, the 12V version will be half that, so the ammeter will just deflect less. As Stinkwheel says, you'll need to reverse the polarity IF you go negative ground.

Test it - you already have a reg/rec in hand, right? If it will charge a 12V battery at 13.5V - 14V when above idle, that's good enough. Then build your (-) ground system.

[stinkwheel]

Don't get me wrong, you'r KBPC will probably work fine, along with whichever regulator you want to use but it seems way simpler to me to just use an all in one reg/rec unit designed to do exactly what you are wanting as one unit with one set of wires. Three yellows to the stator, red to positive, green to earth. Black (if fitted) to a switched live such as the supply to the flasher unit or rear brake switch or (as I've done in the past) just loop it back to the red.

[Mr_84]

I’m always impressed with the knowledge on wiring and electrics you guys have .
 I’m always taking note as my Bullet may have a hopped up motor but the wiring is bog stock ,but giving no trouble.
 I will keep listening so when trouble arises I might have a clue , cheers team 👍

[Raymond]

As Stinkwheel says, you'll need to reverse the wires on the ammeter or it will swing the wrong way. I learned that lesson when I bought a 1970 TR6 650 - last of the pre-OIF Triumphs. The electrics were the worst I have ever seen on a bike, PO had re-wired the ammeter so that as bike drained battery, the ammeter gamely made a +ve of the situation. POs day job? Owns and runs an electrical shop . . .

I'll make a positive of the situation - had to completely rewire the bike, an exercise which taught me a lot about m/c wiring. Didn't quite prepare me for the Bullet's AC & DC system though.

[Paul W]

I’m very happy to leave my 2004 350’s AC lighting and DC everything else well alone. No idea why they designed it that way but it works fine and the only reason I could think of to change the headlight to DC would be to allow an LED bulb to be fitted. But there is so little room in the nacelle that I’d never bother to try, bearing in mind that I seldom need to ride the bike by night.