[Hobbydad]

Can I use an electronic tach on my '11 C5? I've installed them on cars with both points and electronic ignitions, but I haven't got a clue on the bike. Do I need a particular design, for the single cylinder, or for a 4 stroke? Where would I hook it up on the EFI bike? I'm looking at something styled like this, doesn't have to be this particular model:

http://www.cruisercustomizing.com/mini-tachometer/part/BC-49-0293

They talk about dual fire, single fire, ect.. I'm lost, lol.

[jartist]

Something like that should work fine. Hooks up to the ground wire on the coil. The main thing to know is whether the uce sparks on every revolution or every other revolution when you are looking for one or it will show half the rpm or double if you get the wrong one. Anybody have any info on that?

[Ducati Scotty]

Yes, you can hook up a tach BUT you may have some trouble.

I think Dual Fire refers to an ignition system in a four cyclinder motor that fires on every rotation of the engine, rather than every other rotation.  I believe the concept is to fire as the exhaust gasses are leaving to help burn anything unburned.   This matters because you're now getting twice as many sparks as usual and the tach needs to be able to accomodate that.

Also, most evey tach I've seen is for a twin.  You're basically trolling the Harley accessories world.  As far as I can tell some of these can be set to work for more cylinders but not fewer.  I haven't found an electronic tach for single cylinder bikes yet.

Best bet is to call the vendor and ask for what you want, make sure it will work with a single cylidner four strok engine before you buy it.

Scott

[rbelyk]

I found this one, says you need to install an adapter which is included
http://www.baronscustom.com/catalog/display/245/index.html
after rereading it I don't know if it would work

[ace.cafe]

The dual-fire(wasted spark) ignitions allow you to use a tach that is set up for a single fire twin engine, on your single cylinder engine.

For example, on the Iron Barrel bikes, the stock ignition uses points, which are a single fire system which fires every other revolution of the crank. It would need a tach for a single cylinder engine that is single fire.
When we change over to the Boyer electronic ignition, it is a dual-fire ignition, sometimes known as a 'wasted spark" ignition This fires on every crank revolution.
So, you can use a tach made for a single-fire twin, when using this Boyer on a Bullet, because it gives two sparks for each 4-stroke cycle.

So, if your UCE engines have a wasted spark(dual-fire) system, then you can use a tach for a single-fire twin  on it.

[barenekd]

The dual firing ignition system do it because it's easier (cheaper) to set up the system. On a four cylinder engine with a flat crank, two pistons are up at once it only takes one signal to fire them both. The one with compression lights the fire. The other is a wasted spark. By the time the cylinder on the exhaust stroke fires, the exhaust gases are gone. A vertical twin with both pistons rising and falling together, most old English twins, could use the system too.
Bare

[Ducati Scotty]

I don't think UCE is a wasted spark ignition.  My VOM/tach isn't reading double what I expect.

And thanks for clarifying that the dual spark thing is just lazy engineering

Scott

[Hobbydad]

From what I can gather it looks like the majority of these tachs are dual fire, and require an adaptor to be used in a single fire configuration. So I'd need the tach and the adaptor to make it a single fire v-twin tach, that should work with or EFI ignition system, if I understand this correctly.