For those that ask, because they're looking to add a Tachometer.
Here is a topic that I've seen with differing opinions by most everyone. What ignition type is the Road Star? Dual-Fire, Single-Fire.

Does our ignition system fire on the exhaust stroke? Thus giving us Two pulses/fires per complete piston cycle.
Or does it only fire once on the compression stroke? Thus giving us a single pulse/fire per complete piston cycle.

Or perhaps the terminology dual-fire, single-fire is related to how the (a) coil operates, since that's where tachs hook up is on the coil?
Dual fire ignition systems, A single coil would fire cylinder one on compression stroke, then fire cyclinder two on compression stroke. Thus the coil would produce two pulses per two crankshaft revolutions.


And for a single fire system (coil), the coil only fires on the compression stroke.
In single fire mode one coil is connected to the plug(s) of one cylinder only. Each cylinder receives sparks independently and only at the firing point in the compression stroke. Thus the coil would produce 1 pulse per two crankshaft revolutions.

I believe the coil on our R*s fire only on the compression stroke.


Can we as a forum with all the +10 years of R* experience finally nail this down and post this as a closed subject? I mean the R* has been out for quite some time now. I have been going by the statements/posts of some very experienced members here(moderators and bike mechanics). But other senior and experienced R* owners have different answers. Let's get this answered. Please?

Pfluegerak wrote:
For those that ask, because they're looking to add a Tachometer.
Here is a topic that I've seen with differing opinions by most everyone. What ignition type is the Road Star? Dual-Fire, Single-Fire.

Can we as a forum with all the +10 years of R* experience finally nail this down and post this as a closed subject? I mean the R* has been out for quite some time now. I have been going by the statements/posts of some very experienced members here(moderators and bike mechanics). But other senior and experienced R* owners have different answers. Let's get this answered. Please?

First, let me explain the difference in the two kinds:

A single fire ignition can be compared to the type you had on your car when it had a distributor. The distributor was rotated at camshaft speed which is 1/2 engine speed and therefore only fired the plugs on the compression stroke.

On the dual fire system, which the Road Star has, the signal to fire the plug is generated by a pickup coil at the crankshaft thus there is a signal with every rotation of the crankshaft. On this system the plug fires both on the compression stroke and the exhaust stroke. It's a very simple system and doesn't affect plug life at all. Also, our engines don't rev fast enough for there to be any worry about voltage buildup.

Hope this helps.

Scott B.

texasscott1 wrote:
Pfluegerak wrote:
For those that ask, because they're looking to add a Tachometer.
Here is a topic that I've seen with differing opinions by most everyone. What ignition type is the Road Star? Dual-Fire, Single-Fire.

Can we as a forum with all the +10 years of R* experience finally nail this down and post this as a closed subject? I mean the R* has been out for quite some time now. I have been going by the statements/posts of some very experienced members here(moderators and bike mechanics). But other senior and experienced R* owners have different answers. Let's get this answered. Please?

First, let me explain the difference in the two kinds:

A single fire ignition can be compared to the type you had on your car when it had a distributor. The distributor was rotated at camshaft speed which is 1/2 engine speed and therefore only fired the plugs on the compression stroke.

On the dual fire system the signal to fire the plug is generated by a pickup coil at the crankshaft thus there is a signal with every rotation of the crankshaft. On this system the plug fires both on the compression stroke and the exhaust stroke. It's a very simple system and doesn't affect plug life at all. Also, our engines don't rev fast enough for there to be any worry about voltage buildup.

Hope this helps.

Scott B.

Ok Scott. Confirm you're saying our R*s fire both on the compression stroke and exhaust stroke. Thus giving us two pulses per complete piston cycle.
I assume all years for R*'s are in this configuration? Thank you for your response.

Harleys have a dual fire system. The spark plugs in both cylinders are fired at the same time. One cylinder is on the compression stroke the other is on the exhaust stroke.

R* have a single fire system. The spark plugs are only fired on the compression stroke.

Dioc

This discussion already calls for a beer and it's only 6:30 in the mornen

When I added my Baron's Tach, I found out the hard way that our Road*'s are single fire!



BillD in Michigan

DocShadow wrote:
Harleys have a dual fire system. The spark plugs in both cylinders are fired at the same time. One cylinder is on the compression stroke the other is on the exhaust stroke.

R* have a single fire system. The spark plugs are only fired on the compression stroke.

Dioc

I guess the disscussion is not over. But I agree with Doc. Our bikes have 2 coils and 2 plug wires per coil that only provide spark to one cyl each. I do believe our coil could be used as a dual fire if it was used on a bike with only 1 plug per cyl. But on our bike it is only a single fire. Because each coil only provides spark to 1 cylinder. If I am wrong please correct my thoughts.

Anyone that has adjusted their valves by the service manual will note that there are TWO timing marks. One for each cylinder so the R* is a SINGLE FIRE system. If you doubt that pull a plug from each cylinder and stick a screw driver in them and hold the screw driver metal part in each hand and have some one crank it over. Then you can tell if you get zapped by one or both.

Curt wrote:
Anyone that has adjusted their valves by the service manual will note that there are TWO timing marks. One for each cylinder so the R* is a SINGLE FIRE system. If you doubt that pull a plug from each cylinder and stick a screw driver in them and hold the screw driver metal part in each hand and have some one crank it over. Then you can tell if you get zapped by one or both.

I'll take your word for it

CHICKEN!!!!!!!!!!!!