Boyer Electronic Ignition Suspect

Hi Guys. I have recently purchased and restored my 1973 850 Roadster. The bike came with a single Mikuni carb and Boyer electronic ignition. I have a recurring intermittent problem where the engine dies for no reason.

The engine compression is good there are no Intake leaks or other unusual issues detected. The bike starts in 3 to 6 kicks with the choke - and once off choke - settles down and idles well.

The problem starts when out about 3 miles - the engine coughs through the carb, backfires through exhaust, loses power and dies. Pulling to the side of the road, I can kick it back to life where it will run a minutes or two before the problem recurs and it dies again. This stalling and restarting recurs two or three more times and mysteriously goes away and the bike runs fine for the next 10 miles.

This pattern occur each time I take the bike out. That said, I have not ventured out more than 10 miles.

On other occasions, as I approach an intersection with throttle closed the engine will start to falter as if it is going to die. If I rev it the engine backfires and sometimes dies or sometimes it recovers and idles well. Again, this doesn't happen every time and it doesn’t seem to have any particular reason or do I do anything specific to correct it.

I believe the Boyer electronic ignition is suspect and considering A new Tri-spark. But before I pull the trigger, thought I run this by you all for your thoughts.

A search on Accessnorton will turn up some well known failures of the Boyer.

along with the trispark. i had 3 of them fail and replaced it with a boyer micro digital. the pazon sure fire will work OK with new amals or a single mikuni BUT it does NOT have the idle stabilization like either the trispark or micro digital. i am DONE with trispark and the sure fire.
https://www.accessnorton.com/NortonCommando/ign-question.27960/
see this post.

JimC said:

A search on Accessnorton will turn up some well known failures of the Boyer.

Click to expand...

Don't always suspect the Boyer as it could be anything the real problem most have with Boyer is broken wire at the pick up, most other times they are pretty reliable, mine was on my bike for over 33 years without any problem, could also be a bad coil they run good but as soon as they get hot they can play up as you discribe, or something else electrical, sometimes could be carbie troubles and think its electrical, I be looking at a broken wire at the pick up first, but what ever you have to trouble shoot to find the problem one thing at a time.

Ashley

It doesn’t take anything to look. Mine was misfiring. Turned out the plug wires weren’t pushed into the coils all the way. Start the engine, stand to the side and give it a rev. Look for spark arcing from the low tension terminals to the plug wire.

With Boyer ignition every connection has to be tip top
The battery and charging system also has to be tip top
If you are thinking of buying trispark why not buy elektronik saches it's the same spec but without the drama

Earthing is just as important as the feed, I add a dedicated wire from head back to battery. Also if the coils resistance is too low the box overheats and stops providing sparks.

Thanks guys for the replies. I essentially rewired the entire electrical and confirmed all crimped connections. The only wiring I didn’t replace were the handlebar controls and wires. I replaced the 2 coils with CNW replacement single coil. Everything looks well connected including multiple grounds. One thing noted was the PO had stuffed foam rubber pads into the points cavity I suppose to take up space and insulate the Boyer magnetic conductor wires from vibration. I removed the foam and didn’t replace. Is this something that is common with Boyer and should I replace the foam rubber?

What Kommando said re earthing the engine. Someone here posted a while back about how additional grounds (earths) indicated a misunderstanding of basic electricity or the Commando wiring system since (he said) the OEM wiring harness provides adequate grounds.

Humor me (and Kommando) and install a dedicated ground to the engine using a wire/ring connector attached to an existing bolt that screws into the engine.

William Gleason said:

Thanks guys for the replies. I essentially rewired the entire electrical and confirmed all crimped connections. The only wiring I didn’t replace were the handlebar controls and wires. I replaced the 2 coils with CNW replacement single coil. Everything looks well connected including multiple grounds. One thing noted was the PO had stuffed foam rubber pads into the points cavity I suppose to take up space and insulate the Boyer magnetic conductor wires from vibration. I removed the foam and didn’t replace. Is this something that is common with Boyer and should I replace the foam rubber?

Click to expand...

The foam was there to try and stop the wires fracturing
They commonly brake at that point

Confirm direct ground - a dedicated ground wire connected to the head and positive (ground) terminal on the battery?

William Gleason said:

Confirm direct ground - a dedicated ground wire connected to the head and positive (ground) terminal on the battery?

Click to expand...

Yes, the harness should already have an earth wire running from the engine and into the harness but its hidden and some way from the head and electricity does not pass through barrel base gaskets well or hold down bolts on painted barrels, so a red wire direct from head steady hold down bolt back to battery is best. A dual coil makes this less of a requirement as the spark goes out one side and returns the other but if you change to single coils later and forget then you could have problems.

I fitted an allegedly 3 ohm dual coil ie the min ohms the Boyer will take, it was actually 2.9 ohm and this was low enough to cause heating up of the box, twin 6 volts coils of 1.7 ohms each giving 3.4 ohms total cured that issue.

William Gleason said:

One thing noted was the PO had stuffed foam rubber pads into the points cavity I suppose to take up space and insulate the Boyer magnetic conductor wires from vibration. I removed the foam and didn’t replace. Is this something that is common with Boyer and should I replace the foam rubber?

Click to expand...

Failure of the Boyer stator plate soldered connections is a common problem on Commandos as mentioned by others so I suggest you remove the pickup plate and check the soldered joints on the rear of the plate and also that the cable tie is fitted before replacing the foam.

When checking the Boyer pick up wires a continuity check must be done. Vigorously shake those wires with the ohm meter connected.

Again, what Kommando said and remember, the spark plugs 'ground' to the engine. If the engine is not well-grounded there is a tendency to get coil/wire arcing to the frame.

Also check the ignition pickup wires where they pass through the timing case from the points cavity. I've had wires chaff through the insulation and short to ground there.

I would check the fuse holder.. especially if its the original one for glass fuses...

Perversely the earlier Boyer pickup with screw on terminals dosent seem to suffer from this problem

Thank you for all for the valued replies. I now have a check list that I will follow and report back. What are the thoughts on simply replacing the Boyer with another e-ignition system? Also, how would a carb issue play into this? Would a carb issue follow the pattern described? Thanks again for al, the support

JimC said:

A search on Accessnorton will turn up some well known failures of the Boyer.

Click to expand...

Other than the well known pickup wire problem, which has a simple fix, Boyer is the one electronic ignition that has run reliably for decades on scads of different bikes.
It's probably the most reliable EI of them all.
I have 30 year old Boyer on my Commando. Works perfectly, I've never touched it in 16 years of use. It was installed by Pokes cycle in Seattle for the previous owner in 1988.
I did tidy up their kind of messy wiring job after the SS oil line chopped it apart a few years ago, but that had nothing to do with the Boyer Company.

What voltage is showing in your battery when the misfiring occurs?
Also check your ignition switch for poor contact (they corrode internally) and any kill switch for unintentional grounding.

Glen