Britbike forum Forums British motorcycles in general The triple forum T150 wiring polarity

Trying to finish the wiring repair on the T150. It's equiped with a Boyer ignition I was trying to use to determine polarity. 74 service manual section HH

Red is usually + to frame from batt on most British bikes, this says red - to earth what I consider frame ground. As long as red is ground it doesn't matter to me but the Boyer says it must be fed from +
Did they go to that in the 70's for the import standardization or whatever?

You are correct--- red =ground=frame.
On that basis you can connect Boyer + to anywhere on the frame or battery +.
HOWEVER--- in the early days of EI there were quite a few problems with people connecting Boyer + to the frame with paint, grease etc on the frame and not getting a good reliable electrical connection.
So the accepted methodology these days is to connect Boyer + directly to battery +--- thus avoiding any of the possible problems detailed above.
Connecting direct to battery + also means just one connection from black box to battery.
If you connect Boyer + to the frame then with another wire from frame to battery + you have two connections from black box to battery +.
Less connections = less problems.
HTH

You must have misunderstood something so connect according to the Boyer instructions and wiring diagram

http://www.boyerbransden.com/pdf/KIT00054%20(BOX00021).pdf

I use a dc power supply putting out around 13v to check everything's working while I'm wiring and not kill a battery. In the above pic from the section hh in the upper right the battery shows - to red to earth brown blue to +, while the earlier wiring diagram in section h has - to brown blue red to + earth.

The bike had the Boyer unit installed and another Boyer triple ignition in a box possibly older or a spare with the instructions that I using the ignition diagram from. It had no provision for - earth but in a list of tips it said the bit about being fed from.positive. to compound matters there is what looks to be a tympanum Harley reg/rec wired in there. Allegedly the bike ran. Even tho the link failed I'll check the Boyer website for updated instructions.
Edit: no battery was hooked up on the bike when I got it and the wiring was pretty messy, I'm just trying to see whether this guy had it hooked up negative ground. Not even near starting it. Just getting the lights horn and stuff straightened out. The fellow took out the light switch and converted it to a Lucas handlebar switch by using the same switch on both sides, just wading thru the mire.....

I do not know if there is or was a "Harley" version of a Tympanium rectifier/regulator but the one that I have has two yellow wires for the generator output and a red and black wire for the positive and negative output. The case is not electrically connected to any wire.
If that is what you have then it can be wired either positive or negative frame.

With the Tympanium you have the option of connecting your system with either polarity.
For positive Earth you connect the red wire from Boyer to the positive terminal of the first coil and the frame or battery positive. The black wire goes to the negative terminal of the third coil. The white wire goes to your ignition switch.
For negative Earth the red goes to the positive terminal of the first coil and to the ignition switch. The black goes to the negative terminal of the third coil, and white connects directly to frame or negative battery terminal.
On the triple the coils must be 6V, even better with 4V coils. Coils are connected in series with jumpers.

Yes, the battery polarity on that particular diagram is incorrect. + should also be earth/ground.

Tympanum 3135a reg.

Pics from ebay but it's mounted on the rear fender under the coil tray
And looks like what was on my 88 sportster years ago

From the various pictures that I found that is a H*rley regulator. Having only three wires means the case is one output and since it is H*rley, the case is negative. I am guessing it is a zener regulator so it will need airflow to cool it (unless you rarely run high RPMs). You will have to run a wire from the case to the electrical system as relying on fender bolts to a painted frame is not a good electrical connection.

Yeah, after a little adjustment I got the lights working either polarity but if that is grounded (h#rley) - by it's case and is a diode then I might just as well scrap it for a wired version. As I said, wading thru the mire....
So close to putting carbs and exhaust on and hearing this thing!

Supposedly it ran with this setup, so I'm leaning towards the dude having swapped polarity. Which is what this post was originally about. The incorrect diagram hh 19 was what was really confusing me. Nothing like some good old incorrect wiring diagrams! Good thing I got that service manual

Thanks again, titans of the Britbike interwebs!

Not familiar with the Boyer but I think it can be wired either positive or negative ground? Nothing else should be polarity sensitive.

Wired the Boyer as the instructions and got spark with the wire test and positive earth. Ordered a Podtronics to get rid any diode variables.

it has an h4 connector wired in for the headlight. Hoping the polarity won't effect that. Halogen bulb is burnt out considering an LED h4 bulb, being a diode will polarity effect that?
Have an LED in the tr6 specifically for the original Lucas reflector, the T150 has a reflector for a halogen

LED headlight will probably care about polarity. I ended up rewiring my entire T150V as negative ground and used many Honda components and easy to acquire aftermarket. Mine is a rescue, not a restoration. I have a new diagram for it reflecting as-built.

I'm obviously not a purist.

Thanks, pretty much the same here. After going thru I'm 90% sure the bike was running negative ground. Going to move on as is at least till the new rectifier gets here.. going for a nice rider that looks neat and clean.

it's a non matching number bike with a bunch of mods somewhat cafe-d out. Already ditched the clubman bars for some less extreme m style. ( Actually it was b/c the master cylinder was rammed into the gauges and looked like [***] imo)