Ignition Coil Voltage

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350-v-twin
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Re: Ignition Coil Voltage

Post by 350-v-twin » 21 Jun 2017, 15:42

DALORIAN wrote:I am checking the pick up coils and find that they are about 107K ohms to 111K ohms . I don't know if this is correct or not but seems a bit high. also I tried to take the pick up coils off from the camshaft by taking the locknut and the allan screws off but it's stuck and I did not want to damage it by forcing it. I don't know if it needs some kind of a puller or what ?
Sorry, but this completely wrong. I'll explain: measuring the ignition coil, is the ignition coil of the alternator:

Image.

At the top rhs of the engine, a black cable comes out of the engine casing. Inside are 4 wires: 1 red,2 yellow, 1 green. The green one is connected to the fusebox. Take that green wire off the fusebox and measure the resistance (in Ohm), against the mass. You should read something between 180 and 300 Ohm. I have measured many used coils. There were all 220 Ohm. Now below 180 Ohm it will be difficult to start the bike

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Re: Ignition Coil Voltage

Post by DALORIAN » 21 Jun 2017, 22:01

Now , just wondering if the cranking voltage of that green wire sounds about right . It cranks pretty slow with the battery I have but does 30 volts AC without running the engine sound correct ? Also , is there anyway to check the red pickups with a meter ? Thanks

DALORIAN
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Re: Ignition Coil Voltage

Post by DALORIAN » 21 Jun 2017, 23:36

Does that 30 volts AC make any since ? Is this about right or should I worry about the input voltage ? I don't want to waste time with anything that I should not. I imagine the faster that the rotor goes on that ignition coil the more voltage that it will produce but just cranking normally is what I am interested to know the voltage on?

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Re: Ignition Coil Voltage

Post by 350-v-twin » 22 Jun 2017, 11:16

Now, just wondering if the cranking voltage of that green wire sounds about right. It cranks pretty slow with the battery I have but does 30 volts AC without running the engine sound correct ? Also, is there anyway to check the red pickups with a meter?
Forget the battery: the original ignition system has no connection with the battery whatsoever. I'll ask a friend about the output of the green wire. 30 Volts sounds a little low to me, but I'll check.
Does that 30 volts AC make any since ? Is this about right or should I worry about the input voltage ? I don't want to waste time with anything that I should not. I imagine the faster that the rotor goes on that ignition coil the more voltage that it will produce but just cranking normally is what I am interested to know the voltage on?
As stated above: I'll ask a friend who perhaps knows the output of the green wire.

As far as I know you cannot measure the pickup (either red or black). What I should do is to measure the resistance of each red wire. Both readings should be more or less the same, as inside the pickup there are 2 coils. 1 coil per cilinder.

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Re: Ignition Coil Voltage

Post by DALORIAN » 25 Jun 2017, 02:30

The pickups measure around 610 ohms one way only on diode check , so they are quite uniform . . This is quite stumping , because not anything that obviously bad . ```````````````````````````````````

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Re: Ignition Coil Voltage

Post by 350-v-twin » 25 Jun 2017, 19:12

I have tried to make up a complete checklist for both ignition and carburettors. Work down this list systematically, then there's a good chance you get your bike running :mrgreen:
Invitation to forum members, if you can add to this list, please do!

Note: never connect the transducers to 12V, as it will destroy them permanently.

Part I: Ignition

1) Spark on the sparkplug? Yes, sparkplug shows a spark, but engine won't start.
Possible solutions:

a) Check the ignition timing with a strobe (timing of the spark at tdc).
b) Set the gap between the electrodes at 0.5mm. Standard gap of 0.7mm of new sparkplugs is too big for black transducers.
c) Take off the magnet of the pickup, turn it 180 degrees and put it back.
d) The red pickup cable with the markering "1" should be connected to the transducer of the front cilinder (see picture 1 below).

Image

e) Pickup housing mounted the wrong way around (hardly possible). The arrow in the plastic housing should be at the down lhs corner (see pictures 2 and 3 below).

Image

Image

If this does not work, check the flow of petrol, part II.

2) No spark!
Possible solutions:

a) Coil of the ignition blown. Should measure app. 220 Ohm or more (max. 300 Ohm), but no less than 180 Ohm.
b) Transducer(s) blown or bad connections.
c) Please pay attention to all earth conncections. The earth connections on the frame should be bare metal. Make sure of this after a frame was painted or powdercoated. Also the earth connectors of both transducers should be bare metal.
d) Make sure the earth wires of both transducers are not broken. Use fine sandpaper on the connectors for a good earth connection.
e) Black earthwire of the pickup should also have a good connection to earth.
f) Magnets of the flywheel too weak.
g) Sparkplug cable oxidised on the side of the transducer, or on the side of the sparkplug.
h) Sparkplug cap broken.
i) Sparkplug broken.
j) Electrodes of the sparkplug should have a 0.5mm gap.
k) Mess-up electric connections.
l) Check the ignition switch. From the ignition switch 1 green cable goes to the fusebox. Take off only this green wire from the fusebox and try to start the engine.
Note 1: Only thing in this case: if the engine starts, you cannot switch it off with the key. Instead take off a sparkplug cap, or both.
Note 2: When you use the ignition key to switch off the engine, you connect the ignition coil to earth. So if the ignition switch is broken, the connection to earth is kept and you won't have a spark.


Part II: Flow of petrol/gasoline

3) Engine won't start
Sparkplug does have a spark, all possible problems with the ignition have been investigated.

Possible solutions:

Petrol/gasoline
a) Old petrol/gasoline in the fueltank. It has been standing too long. Take out this stuff and use fresh petrol/gasoline. Also take off the float bowls of the carburettors and throw out the petrol/gasoline.
b) Check the electrodes of the sparkplug after start attempts. They should at least be wet of petrol/gasoline.

Fueltank
a) At the bottom of the fueltank dirt, rustparticles block the flow of petrol. Clean out.
b) The venting hole of the fuelcap is blocked. This blocks the free flow of petrol.
c) Filter of the fueltap is blocked with dirt. Clean out.
d) Filters of the Dellorto carbs are blocked with dirt. Easy to find. Take out the bolt of the cover on which the fuel line is connected. Below these covers there is a small plastic filter.

Carburettors
a) Water in the carburettors/floatbowl. Empty out the floatbowls.
b) Old fuel has turned into a kind of gum and has blocked the jets. First indication: thick green layer of gum stuff in the floatbowls.
c) Clean out jets.
i) use compressed air (never use sharp tools),
ii) clean out in an ultrasonic device,
iii) leave soaking in diesel fuel for a while.
d) Level of fuel too high or low, check out the floatlevel. Float could even have a leak. If there is fuel inside a float (hold it against light), replace it for a good one.
e) Float does not cut-off the flow of petrol due to a poor fitting float needle. This "drowns" the engine.
f) Engine sucks "false air". Check rubber parts between the cilinderheads and carburettors on cracks etc.

DALORIAN
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Re: Ignition Coil Voltage

Post by DALORIAN » 28 Jun 2017, 01:49

If anyone has a cranking voltage of the green wire to ground in AC volts please let me know. I don't want to pull the whole ignition coil off and rebuild it if 30 volts AC to ground on the green wire is sufficient to power up the red pick ups and the red dot boxes . It would be nice just to know if I need any work done to the coils before I start replacing everything.

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Re: Ignition Coil Voltage

Post by 350-v-twin » 01 Jul 2017, 13:54

Just received a message from my German friend: 30V from the pickup should be allright, like also the 225 Ohm resistance of the ignition coil.

DALORIAN
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Re: Ignition Coil Voltage

Post by DALORIAN » 03 Jul 2017, 01:15

you mean from the ignition coil , 30 volts should be okay ? Well , that gives me some kind of an idea now. I have to determine how to diagnose the boxes and the pickups . I just checked it again and sure enough it is about 25-30 volts AC coming directly to the right hand box when I disconnect the green wire and put a meter directly on it. I guess that there is no real accurate diagnosis on the red pick ups or the boxes with the red dot aside from replacing them ? If anyone has been successful in testing with a meter or anything really it would be nice . I would hate to order all this and find out it's something else. Thanks for your help.

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Re: Ignition Coil Voltage

Post by 350-v-twin » 12 Jul 2017, 21:52

Did you get your bike running?

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