Why dual bits in a wasted spark system?

Danno said:

Isn't there a wasted spark with dual points? The timing gear is the same and the points are 180 degrees to each other.

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Yes, but there is only one bump on the points cam -so no wasted spark.

comnoz said:

You can actually remove one pickup coil on a boyer plate and jump the connectors and the bike will run fine except it will be hard to start.
I did that one time many years ago to get home after one pickup coil died [fell apart]. I had to roll the bike down a hill to start it. Jim

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Cool.

"Necessity is the mother of invention"

comnoz said:

Not if you have two magnets on the rotor -as Boyers do.

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...which still is "dual bits" as in the inital question.

I was always wondering why none of the developpers of the wasted spark modules which sell in larger numbers spend some thoughts about a properly engineered crank pickup. All of the usual systems go through a gear and a chain and then double the signal to "get cam speed back to crank speed" so to speak - and the only obvious reason to do so is for the sake of convenience.



Tim

Tintin said:

comnoz said:

Not if you have two magnets on the rotor -as Boyers do.

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...which still is "dual bits" as in the inital question.

I was always wondering why none of the developpers of the wasted spark modules which sell in larger numbers spend some thoughts about a properly engineered crank pickup. All of the usual systems go through a gear and a chain and then double the signal to "get cam speed back to crank speed" so to speak - and the only obvious reason to do so is for the sake of convenience.



Tim

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As was pointed out earlier, with pictures, there isn't a lot of room on the alternator side for a ignition. Sure you could find another alternator (ie. Alton) but that just adds to the cost and complexity. And because wasted spark systems work good enough for road work. Any other questions?

swooshdave said:

And because wasted spark systems work good enough for road work.

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As a wasted spark system works better and more stable with a crank trigger and as there is no need to pick-up a cam-speed signal and doubling it to get it back to crank speed this hardly serves as an advantage, doesn't it? :wink:


Tim

Tintin said:

swooshdave said:

And because wasted spark systems work good enough for road work.

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As a wasted spark system works better and more stable with a crank trigger and as there is no need to pick-up a cam-speed signal and doubling it to get it back to crank speed this hardly serves as an advantage, doesn't it? :wink:


Tim

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I said good enough, you said better. Two different things.

Tintin said:

comnoz said:

Not if you have two magnets on the rotor -as Boyers do.

Click to expand...

...which still is "dual bits" as in the inital question.

I was always wondering why none of the developpers of the wasted spark modules which sell in larger numbers spend some thoughts about a properly engineered crank pickup. All of the usual systems go through a gear and a chain and then double the signal to "get cam speed back to crank speed" so to speak - and the only obvious reason to do so is for the sake of convenience.



Tim

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The big problem is "one size does not fit all" and as you know clearances are a bit tight in the street Commando. Every different drive system would require a different pickup system.

I do build crank trigger ignitions on a special order basis to use with the MSD programmable ignition module.
It is the best there is for performance engines -but it's not cheap.
I can build them with VR pickups or Hall sensors.
VR sensors are simply a coil of wire and a magnet so they are durable and not heat sensitive.
Hall sensors contain silicone transistors so they are heat sensitive and more prone to failure, but they are not sensitive to the alternator's magnetic field so they are usually what is necessary on the streetbike. Jim