Wasted spark?

[Bill Owens]

Does a 2004 Stone with hydro motor use the wasted spark type ignition?

[Kiwi_Roy]

I doubt it, usually on singles or twins I think where the cylinders go up and down in unison


Update
LowRyter know a lot more about this
The only bikes I'm familiar seen the NSU Supermax and Kawasakis
I don't think the Brit bikes use it.
I doubt any bikes with 180 or 270 degree cranks use it

[Huzo]

I doubt it, usually on singles or twins I think where the cylinders go up and down in unison


Sent from my shoe phone!

Under the "cone of silence chief"

[LowRyter]

Practical examples of 'wasted spark'[edit]
This system has been widely used, including such engines as the Mitsubishi Evolution 4G63 engine, Mercedes-Benz M104.94x, M104.98x, M104.99x I6 engines; Buick V6 engine 3800 LN3 and newer, Harley-Davidson V-Twin, air-cooled BMW Motorcycles, 1948 Citroën 2CV, Mazda B engine, Chrysler V10, GY6 engine, Volkswagen Mark 3 2.8 VR6 (other than 2.0 ), Saturn Corporation 4 cylinders, Toyota VZ engine 5VZ-FE V6, and Chrysler 1.8, 2.0 & 2.4 engines. Some Ford engines also do. Many Honda and Kawasaki motorcycle and PWC engines also follow a similar design, to allow for a smaller number of more powerful coils to replace a larger number of smaller coils in the same limited space.
In practical use, a V-6 engine would only need three coil packs instead of six. Each individual coil fires the spark plugs in two cylinders simultaneously, the spark plug in one cylinder on a compression stroke where the power comes from, and the spark plug in the other cylinder on an exhaust stroke.
Single cylinder use[edit]
Most single cylinder [four-stroke] engines use the wasted spark system in order to capitalise on the simplicity and reliability of the flywheel magneto. These engines need a flywheel to run smoothly, and the heavy current-generating magnets help provide the momentum while delivering a zero-maintenance drive to the ignition system. Bolted to the end of the crankshaft, this flywheel rotates twice for each compression stroke.

https://en.wikipedia.org/wiki/Wasted_spark

[fotoguzzi]

Under the "cone of silence chief"

for those under 60 or so who may not get the reference,


https://www.youtube.com/watch?v=g1eUIK9CihA

[Kiwi_Roy]

In practical use, a V-6 engine would only need three coil packs instead of six. Each individual coil fires the spark plugs in two cylinders simultaneously, the spark plug in one cylinder on a 

How would a V6 be configured, surely two pistons have to reach TDC together No?

[Bill Owens]

Thanks Foto. I am almost 61 and was thinking WTF. Back to the  reason for  my original question, I have an aftermarket tachometer from a British
company ETB that is not externally adjustable and is clearly market on the back for a 2 cyl. It has always red exactly twice the actual RPM.

[Bill Owens]

Kirby,
I have just been to ETB website and there current tachs are adjustable, however if you look for there older model and the installation page for those older tachs, no go.

[ITSec]

How would a V6 be configured, surely two pistons have to reach TDC together No?

If the V6 crank has a piston pair every 120 degrees, it would be fairly smooth and would have two pistons at TDC every 1/3 of a rotation (though they would be just a tiny bit apart in timing between the left and right bank). Arguably it would run smoother still if each piston was 60 degrees apart, but that would make the crank and cams more complex, and eliminate the chance to use this technique. Ya pays yer money and ya takes yer chances!

[LowRyter]

the early Buick V6 were 90 degree config.  A V8 minus two cyl.
Later Buick modified the crank with splayed throws to get a 60 degree firing order in the same block. 

[Old Jock]

I would also very much doubt it

There are 2 types  of wasted spark systems that can be fitted as aftermarket ignition system on Guzzis

You can have a wasted spark system where the wasted spark occurs when the other cylinder requires a spark for ignition. Usually on a distributor mounted, single sensor, double trigger system. Lucas Rita for example uses that configuration

OR

You can have a wasted spark system where the wasted spark occurs 180 degrees out from the same cylinder requires a spark for ignition. Usually on a crank mounted, double sensor, single trigger system. Sachse for example.

The first type is prone to causing blowback, igniting the mixture on an open inlet valve on one cylinder.

If RPM is high then the burning mixture is just usually sucked back into the cylinder and feels like the bike has missed a beat. HOWEVER if the RPMs are low, when at idle or worse when starting, the mixture flows back through said valve, float bowl catches fire and Presto Cooked Goose.............I think Pete has some nasty pics somewhere to press home the point, I believe that system was a Silent Hektik.

John 

[Kiwi_Roy]

That sounds pretty weird John

[Bill Owens]

Kirby,
Actually the tach was already installed on my Triking when I bought it. I should probably mention it also has the 15M ECU, and yes only works on one configuration.

[Rough Edge racing]

 Wasted spark on V twin bikes? Millions of 45 degree Harleys in the past...Don't know if they still use it...The main advantage is it simplifies the ignition system...Disadvanta ges in performance engines comes from coil limitations...All the aftermarket electronic ignitions for vintage British 360 degree twins use wasted spark....

[Howard R]

My '96 Sport 1100 has a wasted spark system, as will almost any carbed Guzzi with Digiplex ignition, identifiable by the sensor mounted on the bell housing.  On my Sport, there are 4 lumps on the flywheel which are picked up by the sensor, mounted in the area below the right carb.  (Actually, one lump is split into two, as it has to have some way to make one part of the signal look "different" so the Digiplex box can figure out TDC and not just how fast the engine is turning.)  Since the box can only see crank position and not cam phase, it fires each cylinder every time it calculates TDC is coming up.  In theory, the extra spark on the exhaust stroke doesn't hurt anything.

Howard

[Bill Owens]

I just found this info on the ETB website.

3. Will the tachometer work with my vehicle's ECU (Electronic Control Unit)?

Our standard tachometers normally work by taking a signal either from the negative side of the Ignition Coil or from the ECU.

Unfortunately, there is no "standard" signal output from ECU's and they can vary greatly from manufacturer to manufacturer, however our Mk3 tachometers will work with the majority of them and can be calibrated by the user accordingly. If there is no output from the ECU, then the RPM signal can always be taken from a coil pack or  an individual coil (if it is a coil per cylinder setup).

So perhaps all I need to do is connect to - on a coil instead of the ECU.
Won't know for a while as I am cleaning up a number of electrical issues,I prefer not to start it up during cold anyway.

[Howard R]

I just found this info on the ETB website.

3. Will the tachometer work with my vehicle's ECU (Electronic Control Unit)?

Our standard tachometers normally work by taking a signal either from the negative side of the Ignition Coil or from the ECU.

Unfortunately, there is no "standard" signal output from ECU's and they can vary greatly from manufacturer to manufacturer, however our Mk3 tachometers will work with the majority of them and can be calibrated by the user accordingly. If there is no output from the ECU, then the RPM signal can always be taken from a coil pack or  an individual coil (if it is a coil per cylinder setup).

So perhaps all I need to do is connect to - on a coil instead of the ECU.
Won't know for a while as I am cleaning up a number of electrical issues,I prefer not to start it up during cold anyway.

Do you have two coils?  If so, and if the tach has some way to select operation for a single cylinder four stroke, that should work just fine.

[Bill Owens]

Howard,

The issue is that it is labeled as being for 2 cyl but when connected to Ecu indicates EXACTLY twice the actual RPM

[Bill Owens]

And yes I have separate coils

[Kiwi_Roy]

Have you tried it with the tach connected to just one of the coil primaries instead of the ECU
I'm wondering if the ECU has a double output for the tach but two dedicated ones for the coil.

[Bill Owens]

Roy,

   See my last post above. I am going to contact ETB directly. there also might be a solution that involves addition of 1n 4007 diode.

[Bill Owens]

Sorry, 3rd up

[Sasquatch Jim]

2 stroke ignition system on a 4 stroke engine.
In the days of points condenser  ignition a set of points only had so many sparks in them.
Wasted spark single engines used them up twice as fast.

[Dukedesmo]

Wasted spark on V twin bikes? Millions of 45 degree Harleys in the past...

90 degree Ducati V-twin, at least the old carburettor versions (900SS, Monster etc.) with the 2 pickups on the flywheel have wasted spark ignition.

[MadMike]

My Harley Davidson Ironhead Sportster was a waste of a spark...
er I mean had wasted sparks...you know what I'm trying to say...

[Bill Owens]

It seems that I can't get a definitive response about a 2004 1100cc Stone with a 15M Ecu, but I am learning about Triumphs, Harleys , Ducatis and others that I have never owned, and more than likely , never will. Guess I will borrow another Timing light, hook one up to each side and see if I can blind myself in both eyes at the same time.

[Sasquatch Jim]

  And if you can, what will you do with the spare spark?

[rodekyll]

I just installed a digital tach on my 15M system.  I connected it to the tach output.  Set to 2cyl it gave me what I figure was 2x rpm.  Set to 4cyl it's accurate.

Doesn't answer the question, but it implies that the ecu is firing twice.  It's not feeding both coils at once though.  If it did that we wouldn't care about left/right plug wires.   

Maybe someone over at the guzzidiag topic knows.

[Bill Owens]

I just installed a digital tach on my 15M system.  I connected it to the tach output.  Set to 2cyl it gave me what I figure was 2x rpm.  Set to 4cyl it's accurate.

Doesn't answer the question, but it implies that the ecu is firing twice.  It's not feeding both coils at once though.  If it did that we wouldn't care about left/right plug wires.   

Maybe someone over at the guzzidiag topic knows.


Sweet,  That is getting damn close. Still do the timing light think if I can find another one to borrow.

  And if you can, what will you do with the spare spark?

   



Oh I don't know, maybe light another dubbie, maybe a bean fart.

[pressureangle]

I doubt it, usually on singles or twins I think where the cylinders go up and down in unison


Update
LowRyter know a lot more about this
The only bikes I'm familiar seen the NSU Supermax and Kawasakis
I don't think the Brit bikes use it.
I doubt any bikes with 180 or 270 degree cranks use it

Harley-Davidson used wasted spark since the beginning of time. 45 early on one, 45 late on the other.