Redax Generator and Ignition upgrade to Laverda Jota 180 series 1

There has to be a return path for the high voltage spark plug circuit, which is why a single coil has to be earthed through its mounting. It may not matter with the double coil because the other spark plug provides the return path.  

It doesn't make much difference which way you wire the 12V primary side of the coil. There is a preferred direction for the spark to jump across the gap (I forget which way it goes) but on a double coil, the current goes in one spark plug and out the other, so one of them will always be backwards.

Cam
 
The bike wouldn't start heading home up the coast after a Snowy Run,no spark,sorted after tightening the coil mount.Added nilocs,suprised they were not there, to the mount,and use them for anything since.
 
Thanks guys, will strip back the paint on the ends of the mounting tubes on the frame then. Plan is to start the motor this weekend :)
Just picked up a selection of coloured LEDS I ordered for the idiots lights [came from Tassie :o] so next job is to figure out where and how to install them.
If your looking for LEDs this place is a great source for them        http://www.ledsales.com.au/catalog/index.php
 
Dellortoman said:
There has to be a return path for the high voltage spark plug circuit, which is why a single coil has to be earthed through its mounting. It may not matter with the double coil because the other spark plug provides the return path.  

It doesn't make much difference which way you wire the 12V primary side of the coil. There is a preferred direction for the spark to jump across the gap (I forget which way it goes) but on a double coil, the current goes in one spark plug and out the other, so one of them will always be backwards.

Cam
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Um, OK I'm not an electrician of any kind, but I would have thought the spark plug was earthed to the engine and no return circuit per se was required?
 
motoddrob said:
Thanks guys, will strip back the paint on the ends of the mounting tubes on the frame then.
Click to expand...

I ran an earth wire front to back on the bike so that earthing through the frame was only secondary. Connected it to one of the mount bolts inside the headlight, then heading back to the -ve pole on the battery via the mount bracket for the coils. Also have one from the tail light assembly and from the mounting bolt for the starter motor. No problems with earthing from any part of the circuit now.
 
G'day Davo

Basic electrical theory for dummies:  :D

For electrical things to work, electrons need to flow in a circuit from the source, through the appliance and back to the source. A bit like the links in your bike chain, they go around and around.

In the case of a spark plug, the coil is the source of electrons. For the purpose of this explanation, let's not worry about why or how it's a source of electrons. We'll just follow an electron.

The electron leaves the coil, travels aling the HT lead to the centre electrode of the spark plug. It then jumps the spark plug gap to the earth electrode and then into the metal cylinder head. It can't hang around in the engine, it has to get back to the coil. So it travels through the engine to an engine mounting, where it finds its way into the frame. To get back to the coil from the frame it must go through a coil earth connection. That's why single coils need an earth return connection.

 
Dellortoman said:
G'day Davo

Basic electrical theory for dummies:   :D

For electrical things to work, electrons need to flow in a circuit from the source, through the appliance and back to the source. A bit like the links in your bike chain, they go around and around.

In the case of a spark plug, the coil is the source of electrons. For the purpose of this explanation, let's not worry about why or how it's a source of electrons. We'll just follow an electron.

The electron leaves the coil, travels aling the HT lead to the centre electrode of the spark plug. It then jumps the spark plug gap to the earth electrode and then into the metal cylinder head. It can't hang around in the engine, it has to get back to the coil. So it travels through the engine to an engine mounting, where it finds its way into the frame. To get back to the coil from the frame it must go through a coil earth connection. That's why single coils need an earth return connection.
Click to expand...

I think that is pretty much what I said  :D
 
Damn engine is rubber mounted!! though I do have an earth lead from motor to -ve.
Likewise Davo, have an earth wire running to the tail light as well as the front end connecting the switches, h/lights and instruments. Never bothered earthing the frame as everything had a direct connection back to the -ve. So I'll run an earth to the frame then for the coils.
Thanks for the explanation for dummies Cam, when it comes to electrics I'm a complete dummy, though I've impressed myself so far as everything I've connected so far works except for the horn, but it did work when I first wired it. Probably a dodgy earth on the switch as I haven't properly connected it yet. Currently playing with LEDs, bright little fucker they are too
 
motoddrob said:
So I'll run an earth to the frame then for the coils.
Click to expand...

Just splice a wire (or cut that existing earth wire next to the coils and put in a ring terminal on each new end and connect them both to the mount bolt) in from the mount bolt for the coils to the earth wire you already have running back from the headlight rather than stuff the paint on your frame.
 
Dellortoman said:
Sorry Davo, I thought were questioning the need for the coil to be earthed.
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Nah, it was just my poor interpretation of what you wrote, thinking you were saying that a direct connection from the plug back to the coil was required rather than the earth through the engine. And I'm not even from Tassie  :-[
 
Not the quickest on calculus etc meself but...

If the primary ignition coil is correctly connected then upon induction ,the spark plug centre electrode is the negative post and the outer the positive. The actual flow of electrons at spark is from the inner ( hotter ) to outer electrode ( cooler ) electrode .

Because of Benjamin Frankllin ( who quite honestly was a dope ! ..only kidding and got it wrong), we say by convention that the current is flowing from positive to negative. However the electrons in a circuit carry -ve charge and definitely go the other direction ie from -ve to positive.

So, in the secondary coil the high induced voltage results in an electrical pressure at the centre electrode of many 1000s of volts...This ionizes the fuel air mixture and facilitates the jump ie spark. Interestingly the gas mixture becomes part of the electrical circuit.

So, the electrons jump the gap...The current by convention is said to flow in the opposite direction.  

Individual electrons don'ts race around the circuit ..There is a net direction of movement a bit like someone shoving a domino in the domino trick,

joe

 
Gotta weigh in here. Electron flow & the necessity for a complete circuit applies to a battery. Tek coils, single or dual, do not need to be grounded. The plastic case is insulated so the high voltage seeking a ground only travels out of the tower and to the grounded spark plug (path of least resistance). There is no connection between the mounting point of the tek coil and the internal windings; if there were a connection the voltage in the coil would exit on that path and not out of the tower and would be considered a short circuit to ground with no spark @ the spark plug.
 
I have zero idea about any technical stuff but I had a couple of hard to start events during a 4 day ride and on the way home I stopped for fuel and lunch and the bike wouldn't start at all.Tried bump starting with no result so pull a plug and found no spark.This is 60ks from any big town and I am on my own at a petrol station.I start wiggling connections with no result and then I tightened the coil mount and suddenly I had a nice big spark.Loaded up the gear and pushed the button and I was off,zero glitches after that.Spoke to John Wilson about it and got a smile and nod but no com formation about this,just happy to get home on its own steam.
 
IAG said:
Gotta weigh in here. Electron flow & the necessity for a complete circuit applies to a battery. Tek coils, single or dual, do not need to be grounded. The plastic case is insulated so the high voltage seeking a ground only travels out of the tower and to the grounded spark plug (path of least resistance). There is no connection between the mounting point of the tek coil and the internal windings; if there were a connection the voltage in the coil would exit on that path and not out of the tower and would be considered a short circuit to ground with no spark @ the spark plug.
Click to expand...

That makes sense to me :D 
 
Single-output coils have one end of both primary and secondary windings connected together. That common point provides the return path for the high tension.

Dual output coils do not have this feature. As Cam said, the return path is via the second spark plug.

bazzee
 
The secondary coil is in series with earth...I'm not making it up  :LOL:

lets find some " common ground" on this  ;)


joe
 

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