Britbike forum Forums British motorcycles in general British motorcycles in general DOooh ! I DID’NT I kill my Boyer… 🤪 !!

I’ve been moving through steps that led to other things then and working on them,… which has resulted in 3 afternoons of fettling to get this long dormant A65 running. It DID start, Hi RPM, Other thread ended with, … stuck slide.
Sometimes it seems like I am testing Murphy’s Law. The carb work required the air cleaner off. So all back together, tickle and expect a 1 kick start… Not! Kick away, Flooded? Kick away, Spark? Plugs out, check, no spark. Makes no sense, maybe low battery now? Not really low, at 11.8 with head/T-lite on, should spark. Decided to test the coils with power on and jumper wire to act like breaker points. Coils are HOT!! How can that be….? Power shows on the input, but the circuit would need a ground…. ? So, now I know to be careful with air cleaner clamp position!!
The result is after removing the short, still no spark. I think I fried the Boyer with hi current flow over an extended period of looking for the issue. If it Can Happen, It Will happen….. GRrrrr!

KC,

Reminds of Murphy's Laws of Combat! Just a couple from a long list of greats.

Murphy's Laws of Combat

"If the enemy is in range, so are you."

"If your attack is going well, you have walked into an ambush."

"The easy way is always mined."

Sorry, about your Boyer, if that is what happened.

I like to sit them as low in the clamp as possible, but without touching the case, these look like they are quite high up? the position of those clamps can also have an effect of the angle and how high or low they sit when mounted.

P.s. whats the crack with the spade terminal on the + side of the wire? second look it could be a flag terminal?

Id also look at checking the primary and secondary widings of the coils. You might have actually cooked the coil that wasn't touching the clamp, depending on how it is/was wired.

Also, when you find the problem, look at rotating the coils so the terminals are not near anything metalic

AGREED! Thanks.

Hi Kc,


Apologies,” the crack” being “what is with the…” or “what is going on there”. It was one of those where I clicked submit and then thought… ahh it’s a flag terminal, I initially saw the blob of soldered wire poking out at the left.

Nothing wrong with using your own made loom, I make my own and when I start chopping and changing things it’s cheap enough to make a new one or modify what I have.

If the coils are oil filled they will likely be ok. I used to be a sod for leaving my ignition on when I was running points, I’d come back to the bike with 1 hot coil and a flat battery, they were PVL coils and still work to this day. Bloody brilliant coils in that respect!!

For a 6v coil you want about 2-2.2 ohms for the primary windings resistance,
For a 12v coil you want double that.

Secondary windings resistance will be around 9k ohms, less important but with checking just the same. You could get anything like 15k ohms and it would probably still work ok. 9k is about common with the ones I have checked.

Once you know the coil is ok, you can take the plugs out and rest them on the cylinder head. Switching the ignition on/off in rapid succession should send the black box to send a spark to the coils/plugs when the ignition gets turned off, alternately disconnect the stator wires to the little stator plate and brush. Them together with the ignition on would cause a series of sparks to occur.

If you have that, then you should be good to go.

Thanks for the values as a ref. I’ll be back on it after the week-end. Have a new AGM ordered just cause this one is old enough to be ready anyhow, and get that ? Off the suspect list.

KC,
I have an extra Lucas 6CA points plate.

Hah!! 😂 ……back in the Pit Stop days, I remember “Points will get you home” was a rally cry!! Thanks for the memory!

I specialize in “Yestertech”

Thanks Allan,
Checked both 6 V coils individually: As noted, Primary shows 2 Ohm on each. Secondary shows OPEN on both, testing from the plug wire socket to the - or + terminals. They were Very hot, so not surprised at results, but wonder how the heat from the cooking primary damages the fine wire secondary windings. New coils coming, and a new battery also. I have a spare Boyer, and after killing one on a bike before, THIS time I mounted the box and connectors so they are accessible for replacement!

Not really my bag on how these things can fail, but probably the excess heat going through the secondary windings has caused it to act like a fuse and pop??? Just a guess, I really don’t know.

If you have a condenser, a simple test would be to mount a condenser to the positive side of the coil, have a wire from the condenser hanging freely

Connect a wire from the negative side of the coil to a battery.

Connect another wire, but from the positive side of the battery to the threads on the spark plug. (Which you want connected to the ht side of the coil)

Use the loose bit of wire from the condenser you can touch directly against the battery, on-off-on-off in rapid succession. The plug should spark as you’re crudely simulating a points ignition system.

If it does then fit some clamps to the coils in the same place as they were when fitted to the bike and connect another wire from that to the positive side of the battery.

This will then show if the coil is shorting out internally.

not sure why your coils would be bad from killing the Boyer ?
Because your description sounded like the black (negitive ) output from the box was shorting to ground
( through the air filter )
( which would have paralleled and bypassed the coils completely) as a lower resistance path .
... maybe the ground path through the air filter wasn't good enough to fry things instantly ?

Quote old python.
I have a theory........
All Brontosaurus were thin at one end, thicker in the middle and thin at the other end.



The Boyer's output momentarily shorting to + earth will blow the output transistor instantly, they normally fail short circuit,
this will then permanently switch the coils on which will cook them. The internal joint between the primary and secondary
windings may have failed at this time.



https://www.google.com/search?q=python+brontosaur&oq=python+brontosaur&aqs=chrome..69i57j0i15i22i30j0i22i30l2.13839j0j7&sourceid=chrome&ie=UTF-8#fpstate=ive&vld=cid:a9aea158,vid:-dj_X3vexak

I have to be clear about the Boyer: After the coils were shorted to ground at the air cleaner clamp I could not get any spark. Think I mentioned that. Since it’s been a rule that the coils MUST have enough resistance to limit the current through the Boyer (2 six volt coils in series), having a direct short to ground would certainly be a bad Boyer experience.
I guess I could try it again with the new coils just to be sure still no spark, but do not think the old Boyer is OK. It will cost nothing to try the old box, and will not hurt coils in a limited time test. I’d be surprised if I can save it. Will report here just for follow up.

Have a look at the Boyer Troubleshooting guide Here

Apparently switching the ignition off and on should produce a spark if all is well.

Thanks for the LINK!

Yes. It had done that IGN. On/Off in the past when testing and did get spark. It did Not after the hot coils issue. I tried that 1st before moving on to other ideas. When the new coils are in place, will try that again.

As advertised……. New coils show 2 and 7,000 Ohms.

I like your multi meter prop stand.

DIDN’T Kill the Boyer!! Just the Coils!
Interesting that the current that was enough to kill the coils was not sensed by the Boyer!! Just lucky Iguess.