Current on coils?

phliper · Sep 6, 2015

Hi to all,

I am on the way to finish restoring my 74 850 roadster. Tried to start it, but it seems that there are no sparks in the cylinder. Is there a way other then removing the spark plug from the cylinder and kickstart the bike, to verify if there is electricity comming from the coils witch I replaced by 2x6v.

Thanks,

Phil

L.A.B. · Sep 6, 2015

Points? Or electronic ignition (if so, which type)?

phliper · Sep 6, 2015

Electronic ignition

L.A.B. · Sep 6, 2015

phliper said:
Electronic ignition

Which type/make?

74ok · Sep 7, 2015

you can use (if u have) a timing gun to check for spark

phliper · Sep 7, 2015

L.A.B. said:
phliper said:

Electronic ignition

Click to expand...

Which type/make?

I don't know, is the ones that were on the bike before the restoration process began... There is nothing written on them.

L.A.B. · Sep 7, 2015

phliper said:
L.A.B. said:

phliper said:

Electronic ignition

Click to expand...

Which type/make?

Click to expand...

I don't know, is the ones that were on the bike before the restoration process began... There is nothing written on them.

Description?
Pictures?

phliper · Sep 7, 2015

I changed the old electronic ignition from Boyer for a new one. The red connects to the + of the primary coil, the black to the - of the secondary coil. There is a wire from the + of the primary to the - of the second. The white wire connects to the positive ground of the bike. There is also a wire from the + of the primary coil to the positive ground.

I did a test with a multimeter, and on 200 ohms, I got 2.3. Which seems to be ok.

Still no spark.

Any ideas.

L.A.B. · Sep 7, 2015

phliper said:
The white wire connects to the positive ground of the bike.

Boyer box white is negative so it should be connected to the white/yellow or white/blue negative wire (from the kill switch button) not connected to ground for positive earth/ground.

http://www.boyerbransden.com/pdf/KIT00053.pdf

19) Connect the white-blue wire (the one removed from the ballast resistor) to the white wire from the transistor box.

However, if possible, connect the Boyer white directly to the white/yellow, the basically unnecessary white/blue wiring section will then be bypassed.

phliper · Sep 7, 2015

Thank you LAB! I will try this after supper

phliper · Sep 8, 2015

Did the thing, plug the white with the yellow/white (and did a test with blue/white), no luck, no sparks. Still have 2.3 ohms on the multimeter.

If I have 2.3 ohms, do this means I got current? No...?

L.A.B. · Sep 9, 2015

phliper said:
If I have 2.3 ohms, do this means I got current? No...?

2.3 Ohms where, exactly?

Are you getting 12V at the white/yellow to white (Boyer box) connection (ignition ON)?

If so, and if both box and coil reds are securely grounded, then try going through the test procedure: http://www.tioc.org/boyer/boyertestnewweb.htm

phliper · Sep 12, 2015

So, I have done a lot of tests and here are the results :

On the multimeter :
Batterie : 12.9v (20v option on the multimeter)
Coils : between the - and the + 2.6 ohms (200 option)
Boyer electronic : same as supposed by Boyer testing procedures
Coils and spark wire (the red stick is on the + of the coil and the black stick is at the end of the wire : 8.9 (200k ohms option)

This might be my problem? I read some thing about this value being faulty if under 10. That is was supposed to be between 10 to 25. Is that right?

My spark plugs are brand new.

Thanks again for helping me!!

L.A.B. · Sep 13, 2015

phliper said:
Coils : between the - and the + 2.6 ohms (200 option)

"2.6" Ohms seems slightly high (although you did mention 2.3 before but didn't say where the reading was taken), a "6V" coil should typically give a reading of around 1.9 - 2.3 Ohms measured across the primary terminals.

phliper said:
Boyer electronic : same as supposed by Boyer testing procedures
Coils and spark wire (the red stick is on the + of the coil and the black stick is at the end of the wire : 8.9 (200k ohms option)

This might be my problem? I read some thing about this value being faulty if under 10. That is was supposed to be between 10 to 25. Is that right?

No, not in my opinion, as the secondary readings should be somewhere around 5 kOhms (20k setting).

As you said you measured from the end of the (HT) spark wire I suggest you disconnect the wires and re-check the coils.

A known good standard (17M6) Lucas 6V coil taken from my spares box measures 1.9 Ohms, primary, and 4.92 kOhms secondary.

What make/type are the "6V" coils?

Are you absolutely certain power is reaching the Boyer box (12V at white/yellow)?

phliper · Sep 13, 2015

Sorry, error from my keyboard, it was 2.3 ohms taken on the multimeter, on the primary coil, between the + and -. Same thing on the secondary coil, 2.3 between + and -. The red stick on the + and black stick of the multimeter on the -.

L.A.B. · Sep 13, 2015

phliper said:
Sorry, error from my keyboard, it was 2.3 ohms taken on the multimeter, on the primary coil, between the + and -. Same thing on the secondary coil, 2.3 between + and -. The red stick on the + and black stick of the multimeter on the -.

Good. It shouldn't matter which way around the "sticks" (probes) are as the coil readings should be the same either way-but what we really do need to know before we can progress any further is if battery voltage is definitely getting to the Boyer box (from white/yellow)?

phliper · Sep 13, 2015

L.A.B. said:
Good. It shouldn't matter which way around the "sticks" (probes) are as the coil readings should be the same either way-but what we really do need to know before we can progress any further is if battery voltage is definitely getting to the Boyer box (from white/yellow)?

After testing the white/yellow. I got 10.5 volts between the wire and the frame.

Any other ideas? I am running out of ideas!

L.A.B. · Sep 13, 2015

phliper said:
After testing the white/yellow. I got 10.5 volts between the wire and the frame.

If as you said you were getting 12.9V at the battery then 10.5V does not sound all that good. Perhaps try running a jumper wire from the battery(-) to Boyer white?

phliper said:
Any other ideas? I am running out of ideas!

Have you tried doing the "scratch" test as described in the Boyer troubleshooting article: http://www.tioc.org/boyer/boyertestnewweb.htm

Did you re-check the coils as I suggested? If so, what were the results?

It could just be that the Boyer box (or pickup) is faulty?

phliper · Sep 13, 2015

I should have mist your suggestion about testing the coils with a different test. What is that test?

phliper · Sep 13, 2015

L.A.B. said:
If as you said you were getting 12.9V at the battery then 10.5V does not sound all that good. Perhaps try running a jumper wire from the battery(-) to Boyer white?

Tried the jumper and I got 12.9 direct a the white Boyer, still no luck of getting a spark with the spark plug.

Current on coils?

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