Ignition System

[Fat_Wing]

On a 1200 when the coil sparks does it spark both plugs on the coil? In other words is it performing an ignition for the cyclider that is on the compression stroke and a waist spark for the cylinder that is on the exhaust stroke?

I'm tring to figure out what type of custom tachometer will work on my bike. The tack will only be attached to one coil but that coil (I think) is sparking once for every 1 RPM.

Thanks

FW

[Try]

On a 1200 when the coil sparks does it spark both plugs on the coil? In other words is it performing an ignition for the cyclider that is on the compression stroke and a waist spark for the cylinder that is on the exhaust stroke?

I'm tring to figure out what type of custom tachometer will work on my bike. The tack will only be attached to one coil but that coil (I think) is sparking once for every 1 RPM.

Only one cylinder receives a spark from the distributor at a time. Each pair
of spark plugs (1 - 2) (3 -4) has its own ignition circuit.

Great explanation of the Ignition System

The GL1200 ignition control unit electronically varies ignition timing according
to engine speed when the transmission is in 1st through 3rd gears. When the
transmission is shifted into 4th or 5th gears, a gearshift sensor signals
the ignition control unit to electronically vary ignition timing according
to carburetor vacuum.


I think you only need one attacment to your custom tachometer.

[Fat_Wing]

Try

Looking at my wiring diagrams that just doesn't sound correct to me.

This is what I know.
1. Two pulse generators, one ignition module, two coils and 4 plugs.
2. The pulse generators just send a magnetic signal to the ignition module. No big deal here.
3. When the key is in the run the ignition module and both coils get power from the ignition switch.
4. The ground side of one coil goes to the fuel pump relay and the ignition module (blue/yellow wire in my book).
5. The ground side of the other coil goes to the tachometer and the ignition module(yellow/blue wire in my book).

So doesn't all this mean that the coils have to fire both plugs each time the ignition module opens the ground side of the coil?

Thanks

FW

[Dougal]

One coil and pulse unit fires 2 plugs at the same time. The so called wastedspark system used on many of Honds multi cylinder engines.

Dougal

[Fat_Wing]

Cool

That's what I needed to know. So a tachometer hooked up to one coil will need to read one spark for every RPM.

Thanks

FW

[Fat_Wing]

Only one cylinder receives a spark from the distributor at a time. Each pair
of spark plugs (1 - 2) (3 -4) has its own ignition circuit.

Great explanation of the Ignition System

This is a great explanation of a standard Automotive ignition system but Honda GL1200 ignition doesn't have a distributor and is a bit different than the auto one.

The GL1200 ignition control unit electronically varies ignition timing according
to engine speed when the transmission is in 1st through 3rd gears. When the
transmission is shifted into 4th or 5th gears, a gearshift sensor signals
the ignition control unit to electronically vary ignition timing according
to carburetor vacuum.


I think you only need one attacment to your custom tachometer.

Can anyone tell me what the ignition module stratagey is in 1st, 2nd and 3rd gears (engine speed) and then 4th and OD (vacuum).

This is what I know:
1. In 4th and 5th gear the ignition module gets a ground signal from the shift sensor. The module then knows that the trans is in 4th or 5th gear and controls the ignition timming based on carb vacuum (or engine load). Is this an timming advance stratagey or what?
2. In 1st, 2nd, 3rd gear the ignition module doesn't get a ground signal from the shift sensor so the module uses a engine speed stratagey (to advance timming I'm assuming). What is this stratagey? What is full timming advance? And when will it reach full advance, 3000 RPM, 4000 RPM?

[Try]

This is a great explanation of a standard Automotive ignition system but Honda GL1200 ignition doesn't have a distributor and is a bit different than the auto one.

Agree, I was to fast and inaccurate!!

Can anyone tell me what the ignition module stratagey is in 1st, 2nd and 3rd gears (engine speed) and then 4th and OD (vacuum).

This is what I know:
1. In 4th and 5th gear the ignition module gets a ground signal from the shift sensor. The module then knows that the trans is in 4th or 5th gear and controls the ignition timming based on carb vacuum (or engine load). Is this an timming advance stratagey or what?

2. In 1st, 2nd, 3rd gear the ignition module doesn't get a ground signal from the shift sensor so the module uses a engine speed stratagey (to advance timming I'm assuming). What is this stratagey? What is full timming advance? And when will it reach full advance, 3000 RPM, 4000 RPM?

I can't help with this specs, but I found an interesting article about Active Ignition Timing

[Fat_Wing]

I can't help with this specs, but I found an interesting article about Active Ignition Timing

Thats cool info about just how much can go into mapping your timming. Every little bit helps, with power and emissions.

Thanks

I still would like to know the stratagy the GL1200 ignition module uses for controlling timming.

I think it advances it more and quicker in gears 1, 2, & 3 and then for gears 4 and 5 it advaces less so that spark knock isn't a problem.

What do you guys think?

FW

[Try]

Thats cool info about just how much can go into mapping your timming. Every little bit helps, with power and emissions.

Another one: 3D Ignition control

I still would like to know the stratagy the GL1200 ignition module uses for controlling timming.

I think it advances it more and quicker in gears 1, 2, & 3 and then for gears 4 and 5 it advaces less so that spark knock isn't a problem.

What do you guys think?

I have no good answers yet, but I'm looking. Quite interesting stuff.

[Fat_Wing]

I'll take a shot at this FW.

Question A: Can anyone tell me what the ignition module stratagey is in 1st, 2nd and 3rd gears? What is this stratagey? What is full timming advance? And when will it reach full advance, 3000 RPM, 4000 RPM?

Answer A: Total 35 degress advance electrical with the curve starting at approximately 1500 RPM and all in at 3200 RPM.


Question B: What is the ignition module stratagey in 4th and OD?

Answer B: The engine gets another 10 degrees electrical advance at light/medium throttle loads when in 4th or 5th gears for a grand total of 45 degress advance when cruising above 3200 in 4th or 4th gears.

Question C: I think the module advances timing more and quicker in gears 1, 2, & 3 and then for gears 4 and 5 it advaces less so that spark knock isn't a problem. What do you guys think?

Answer C: I believe that the ignition advance curve is fixed and the same throughout all the gears and the only time it varies is in 4th or 5th when the extra 10 degrees of advance is engaged by the ECU.

Vic

Thanks for the good info

FW