CJ750 toolbox
Dariusz Weicha's M1M The Red Pig goes electronic

So you are tired of dealing with the points, or like me, you want to avoid dealing with them in the future?... My solution was to install the Boyer Bransden Electronic Ignition Mark 3. Your engine will run better, smoother and cooler!

I will tell you what steps I took to install it on my Red Pig, but I can’t take any responsibility for your installation. All CJ’s are different. It worked in my case, but you take your own risk for altering your CJ’s original set up! I can only tell you what I did…


There are two versions of the ignition kit, one is analogue the other one is digital. I chose the analogue version for its simplicity and the lower price. I am also convinced that it is perfectly sufficient for a "low performance" (no offence intended) kind of a bike like CJ.

I ordered my Boyer set from Rocky Point Cycle in Ohio (phoned: 937-376-9792, asked for Stan) and paid about $100 including shipping. The kit was originally for a Twin Norton or an Atlas motorcycle. Stan was very helpful in answering my questions and making sure I got something I could work with.

I started my project by removing the entire CJ distributor assembly from the engine block. I unscrewed all the little bolts and removed the condenser and the points plate. Then I removed the inside bob weights by taking the springs off and pulling the weights off the studs with pliers. They slid right off.

Then I removed the rivet holding the universal joint connection together. I grinded the rivet off and pushed it out.

I made sure I didn’t lose the little swivel pin that made the actual universal joint connection. Now I could take the camshaft right out of the distributor assembly.

I noticed that the two studs that used to hold the bob weights were riveted in place and that I needed to drill them out from the back to remove them.

Once I got rid of them I was ready for threading the top of the camshaft with a 5/16, fine thread dye. I went very gently, back and forth, using a lot of cutting oil. I went as far as I could, without stripping the threads I just cut. The steel was soft and the job was very easy.

Now I got the shaft ready to receive the magnetic rotor from the Boyer Ignition Kit. But the rotor turned out to be a bit too deep and was lifting the stator plate.

I needed to cut off the flange at the bottom of the rotor.

Once this was done I could screw the rotor right on my newly threaded shaft with the magnets facing up. Since the shaft rotation is counter-clock-wise on a CJ, the rotor shouldn’t loosen up by itself, but I decided to secure it with a spring washer and a 5/16 fine thread hex nut anyway.

I was ready now to slide the shaft back into the distributor cup, where I found it originally and put the stator part right on top.

With the coils facing up I placed it the same way I would be placing the old points plate in the cup. I rotated the rotor to see if it rubbed against any parts of the stator. If it did, it would mean that the stator was not perfectly centered or the rotor sat too high. One could lower the rotor by girding more of the flange off on its back side. This should be done very carefully though... I grinded off too much and had to use a flat hex nut to raise it again.

When this fitting was done I was ready to reassemble the shaft universal joint connection and use a nail of the appropriate thickness as a rivet for the joint holding ring.

Once done with this, I mounted the stator plate inside the distributor cup with the same screws I took of the original plate. I needed to drill two small holes on the perimeter of the stator to attach it the way the old points plate was attached. The factory cut slots on the stator did not fit the CJ holes. I moved the stator plate around to make sure the rotor didn’t hit it or didn’t rub against it. Once the stator was perfectly centered I tightened the screws.

I was done with making my electronic ignition assembly. I connected the yellow/black and the white/black wires from the transformer box into the corresponding stator wires. I did not like the supplied bullet connectors and used small twist connectors instead. I could have soldered them together as well. I had to make sure they were tucked away from the shaft and there was no strain on them.

I slid my new electronic ignition assembly back into the engine block and made sure the gears got properly engaged.

The other wires from the transistor box I connected in the following fashion:

The white wire – all the way out to the battery negative terminal.

The black wire – to the negative terminal of the coil or to the black wire that used to attach to the old condenser.

The red wire – to the positive terminal of the coil, joining the positive wire coming from the ignition switch. The latter wire was already attached to the coil under the original set up, so I didn’t need to look for it.

I was ready to run a check. I took the spark plug wires off, installed old spark plugs, grounded them, turned the ignition on and watched if when kicking the bike or using my electric starter I got a nice, fat, blue spark. I did, so now I needed to work on the timing.

I looked through my flywheel peep hole and set the flywheel to 36 degrees BTDC (well, it is not actually what I started with, but it is what I should have done!). The ignition assembly needed to be aligned accordingly. There are two static timing holes on the ignition stator. One before the magnet passes the coil and one after. I used the one before (up stream of the rotation if you will).

Without moving the engine flywheel, I rotated the ignition assembly to see the top of the magnet screw through the hole in the stator. I tightened the ignition assembly bracket and the mounting nut on the engine block, replaced the original plastic cover and started the engine. It worked like a charm! Originally I started my tuning according to the Boyer recommendation for Norton with setting the flywheel to 30 degrees BTDC, but after playing around with a timing light I got to conclusion that setting it at 36 degrees BTDC was the right way to do it for a CJ(unless I read the instructions wrong).

If you are curious how I figured out how 36 degrees turns out to be 6 degrees, here it is.

Well, the base for it is that the factory holes in the Boyer ignition stator are drilled at about 31 degrees BTDC. But if you set your flywheel at that angle, there will be almost no advance at all – both will be at about 30 degrees BTDC! And you want to be 6-8 degrees BTDC at idle and 30 degrees BTDC at max rpm’s. To make sure my way of thinking was right I had to check it with the engine running.

When using a timing light with the advance control feature I had to remember that the advance angle showing on the timing light is double of that showing on the flywheel marks. It is due to the timing light counting each spark as a full revolution, but in case of many bikes both spark plugs fire at the same time, every half of the revolution. So if I wanted to get it right to 6 degrees BTDC in idle (at about 1000 rpm, which on the timing light showed as 2000 rpm), my timing light had to show 12 degrees when the flywheel mark was showing steady at 0 degrees… If I didn’t use a timing light with the advance feature, running in idle the strobe should flash the flywheel at 6 degree mark. When I revved the rpm’s to about 4000 the mark would be 30 degree BTDC.

Again, using the timing light with the advance feature and mark 0 on the flywheel, my timing light had to be set to 60 degree advance to see mark 0 on the flywheel at 4000 rpm’s.

So when I got it all set up and tuned the way it should be, and looked at what angle the top of my rotor magnet screw appeared in the stator hole – it was at 36 degrees on the flywheel!

And it makes perfect sense since these holes are drilled at about 30 degrees and you want to be 6 degrees BTDC.

My final touch was fabrication of a little bracket to hold the transistor box close to the ignition housing.

Now my Red Pig purrs like a happy kitten!

It rides smoother and, believe it or not, the engine sounds better! I can idle at 800 rpm and I don’t have to worry about it dying in traffic.

I highly recommend doing it!


For kit orders within the USA I recommend:


For troubleshooting and additional info I recommend:


and http://www.britcycle.com/Manuals/33101inst.pdf

Negative ground installation clarification can be obtained at:


For general info on the Boyer Ignition units: