Boyer magnets.

seattle##gs · Feb 1, 2023

I have a 1972 Norton. Trying to start it is a real bear. Everything is new. Vicious kick back. Once it runs it runs well. I swapped out the Boyer black box. No change. I swapped out the pickup plate...no change. Only thing left is the magnets. used the screwdriver test for the magnets, one side is a little weaker than the other though neither is all that strong. New wiring. New Dual Dyna coil 5 ohm. Vicious kickback. Anybody had a weak magnet problem? Symptoms? Could the Dyna coil be a problem? Never had a problem with Dyna coils
I have a new Shorai battery ...reads 13V.

baldy · Feb 1, 2023

Kick back is usually caused by timing too far advanced. Check both sides on a timing light.

Torontonian · Feb 1, 2023

baldy said:
Kick back is usually caused by timing too far advanced. Check both sides on a timing light.

Yeah , just loosen off the pillar bolts and move the plate a tad until that nonsense stops .

seattle##gs · Feb 1, 2023

I used a timing disc, discovered that 34 degrees with the pointer is actually 31 degrees It is static timed but should be fairly close. Does not account for the vicious backfire

Torontonian · Feb 1, 2023

seattle##gs said:
I used a timing disc, discovered that 34 degrees with the pointer is actually 31 degrees It is static timed but should be fairly close. Does not account for the vicious backfire

Well then replace the steel rotor piece with those small magnets . It's old , right ? Magnets don't last forever . They get weaker with time . Particularly if stored up to a chunk of steel the magnetism can then bleed into . That's why rotors come fitted with Keeper shells , to help stop any potential bleedings of magnetism out . ( Never toss those shells out BTW . ) . Before I learned this , I used the rotor as a way to keep the little bits attached to it and to not lose any .
Treat yourself to a NEW battery and clean up ALL connections to the Boyer pickup plate .

seattle##gs · Feb 1, 2023

I ordered a new rotor today

kommando · Feb 2, 2023

seattle##gs said:
It is static timed but should be fairly close.

No, can be up to 8 degrees out, I changed boxes and the variation in the electronics within their tolerances made it 8 degrees retarded after I checked with a strobe.

baz · Feb 2, 2023

I don't know if this could be your issue but I once did some work on a mates MK3 commando
He'd fitted Boyer ignition and it wouldn't fire at all
It passed all the usual tests statically
But nothing when you kicked it over
In the end I realised that the rotor was not close enough to the pickup
I can only imagine something was wrong with the camshaft?
I made a shim to fit into the taper for the rotor ,this pushed it forward enough to activate the pickup
The bike fired right up

cliffa · Feb 2, 2023

baz said:
I don't know if this could be your issue but I once did some work on a mates MK3 commando
He'd fitted Boyer ignition and it wouldn't fire at all
It passed all the usual tests statically
But nothing when you kicked it over
In the end I realised that the rotor was not close enough to the pickup
I can only imagine something was wrong with the camshaft?
I made a shim to fit into the taper for the rotor ,this pushed it forward enough to activate the pickup
The bike fired right up

I‘m pretty sure that Boyer themselves note that on one of their instruction sheets as well.

baz · Feb 2, 2023

cliffa said:
I‘m pretty sure that Boyer themselves note that on one of their instruction sheets as well.

I didn't know that

cliffa · Feb 2, 2023

Just found it..

”I Have Sparks On Switching On And Off But Not On Cranking
Disconnect the wires from the ignition box that go to the stator plate. With the ignition on, touch these two wires together, making and breaking should produce a spark at the spark plugs. If sparks are present then the ignition box is most likely to be in good order, if none are present the box is faulty. The only units that will not trigger in this way are the Kawasaki KH, Kawasaki S and Suzuki GT units. Check that the rotor magnets are running within the two metal pole pieces. On British machines, if necessary the rotor can be moved out slightly by placing a thin metal shim around the taper. The ignition will not fire if turned by hand at less than 200 RPM.”

The complete troubleshooting guide is here..

Boyer Bransden Electronics Ltd - Fault Finding

seattle##gs · Feb 2, 2023

baz said:
I don't know if this could be your issue but I once did some work on a mates MK3 commando
He'd fitted Boyer ignition and it wouldn't fire at all
It passed all the usual tests statically
But nothing when you kicked it over
In the end I realised that the rotor was not close enough to the pickup
I can only imagine something was wrong with the camshaft?
I made a shim to fit into the taper for the rotor ,this pushed it forward enough to activate the pickup
The bike fired right up

That is a really weird problem, how long did it take to finally discover the problem? I'll check it today.

seattle##gs · Feb 2, 2023

kommando said:
No, can be up to 8 degrees out, I changed boxes and the variation in the electronics within their tolerances made it 8 degrees retarded after I checked with a strobe.

I never rely on static timing...just enough to get it started then strobe it. I have static timed umpty Boyers and noticed a variation in timing even though I make every effort to line up the red dot perfectly in the window. Did not realize there would be a variation tin the electronics themselves.

baz · Feb 2, 2023

seattle##gs said:
That is a really weird problem, how long did it take to finally discover the problem? I'll check it today.

It took a little while for the penny to drop
I was passing a magnet across the front of the pickups and it would spark
But turning the motor, nothing!
As said I don't think this is your problem
Just something to watch out for

seattle##gs · Feb 6, 2023

I replaced the rotor with a new one. Same problem. Ran a wire direct from the battery to the Boyer ..no improvement. Next, I will run a wire from the boyer ground to the battery though I don't expect any improvement. Back to the Dyna coil...any possible way it could be causing problems? Usually they work or they don't. Anyway the podtronics could influence the timing?

hhh · Feb 7, 2023

5 ohms is a little high. I try to aim for 3 and definitely no more than 4.5. The Boyer instructions that state you can run your 12V coils in series is a bet of a stretch, but if they didn't say that, they wouldn't sell as many Boyers. Boyers are very sensitive to power quality. A spring loaded fuse holder is bad because at certain frequencies it will hit a harmonic and disconnect which makes the timing go full advance for a moment until it can resync. BTW, One source of timing advance is the magnetic field increases with velocity, so the crossover point happens sooner at higher RPM. I would guess that weak magnets would hit a point where they won't even trigger below a given RPM. Also, checking both sides is a waste of time as both magnets and both stator coils are involved with the timing for every revolution. If you have a one sided issue with a Boyer, you can be sure it's plugs, wires, or coil (or half-coil.)

seattle##gs · Feb 7, 2023

Weak magnets was the answer, everything good now. Keep this in your files..a lot of Boyers are old by this time.

hhh · Feb 7, 2023

So your replacement rotor yesterday had weak magnets too?

Schwany · Feb 7, 2023

I would not be that surprised if the dedicated ground wire back to the battery didn't fix the issue after the timing was retarded a little. My TriSpark is grounded with a dedicated wire to the battery. Works fantastico. The Boyer works alright, but didn't idle as smoothly.

Too bad I missed this. I have a MkIV Boyer in a box I'll never use. You could have had it for a 1.75 liter bottle of Silver Kirland Tequila. However, you would have had to come to NE Seattle to get it.

Boyer magnets.

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