6v to 12v and then electronic ignition

[B Murphy]

Hi
I've looked at the forum messages about going from 6v to 12v but can't find what l'm after. I'm looking for an easy plan to follow, going to 12v from 6v and then installing a 12v boyer electronic ignition, if anyone has any links if possible please.

Just one question though, when connecting the alternator green/yellow and green/black together to make the 12v, what do you do with the green/yellow that has been chopped?

The bike is a 1959 C15 with distributor, positive earth.

[JulianS]

The plan would depend on which voltage regulator you are going to use. They will come with some instructions. See link to Boyer Powerbox;

http://www.boyerbransden.com/pdf/PBOX00108.pdf

having joined the green/yellow and green/black from the alternator the green/yellow which you have disconnected and which goes to the ignition switch is redundant.

[berniej]

Hi B,

Lots of options out there in Google land but I would recommend getting a copy of Rupert Ratio's book on the BSA singles (engine).
As well as a huge amount of excellent tech info he also covers options for converting to 12V including circuit diagrams.

As Julian says, there are a number of options for the rectifier/regulator electronics but the basic principle is similar.

I'm currently doing the same with my B40 which (I think) will have exactly the same wiring as your bike. When done, the 'E' option for emergency starting will be redundant as the full alternator output will be fed through the rectifier/regulator to the new 12V battery so 'I' is the option for starting.

You haven't mentioned if you're also switching to -ve earth but it shouldn't be an issue if you do - this is a good idea if you want to go with LED lighting as most (of the good ones) are currently -ve earth.

Apart from a new 12V coil I don't think that you will have to make any other major changes (except for the blubs!!).

Cheers,
Bernie

[B Murphy]

Do you know if this 12v MB9U AGM battery (mentioned in "which battery") will fit the C15.

[B Murphy]

Hi Julian

I'm confused now, this will be first ever attempt at installing one of these, I've always stuck with points.

I have the Boyer Micro MK1V kit for the distributor model. When you say depends on "voltage regulator" do you mean the black ignition box which comes in the kit.

On the wiring plan in the instructions it states a P. Box with alternator wires going to it. Is this the small aluminium rectifier which is already on my bike.

Do I have everything in this kit that I need or do I have to buy these other things i.e. voltage regulator and P.Box.

[JulianS]

The Boyer Powerbox, which rectifies the alternating current from the generator and regulates the voltage is separate from the ignition box which controls the sparks.

On the original 6 volt setup there is no voltage control, the rectifier you have is just a rectifier it does not regulate voltage.

There are other units available which rectify and regulate the alternator. Not to be confused with dynamo regulator.

Link takes you to the single phase Boyer, not cheap;

www.britishbikebits.com/boyer-bransden-power-box-single-phase-triumph-bsa-norton-royal-enfield

[B Murphy]

Thanks Julian, now ordered.

[B Murphy]

Just out of interest, has anyone else installed one of these to their C15 distributor model.

[SUPERGRUMPS]

I have a C15 which has been converted to 12v, quite straight forward and worth the effort, if just for the easily obtainable bulbs and batteries. I have toyed with converting to electronic ignition, but  is it really worth the bother,. I will be watching this space to see if anybody replies to your question, regards

[B Murphy]

Well I converted the C15 to 12v and installed the electronic ignition. It started up first kick but I still had the cough and stall issues, so at least I knew it was a carb/fuel issue. I had brought a brand new Monobloc and a new concentric but could not get it running right, changing jets, carb off... on... off......so I bit the bullet and installed a brand new £23 free post from China OKO carb and wow the bike now runs like a modern bike. The throttle response is fantastic, no coughing, spiting, stalling. I'm not saying Amal are rubbish just saying I wished I found OKO carbs sooner in life.