Coil over Plug Conversion?

[Bob Young]

Has anyone here considered/tried a coil over plug conversion?
Over on another site (Concours Owners) there is an active thread about such a conversion. Seems like it could be adopted for the GS1100 G's.
I looked in the search feature and didn't find anything, but then, maybe I didn't go far enough.
Thanks for any replys,
Bob Young
bytes88@nctv.com

 

[BassCliff]

Hi Mr. Bob Young,

Are there any advantages to this setup? It looks unnecessarily complicated (more failure points) for these simple, reliable motorcycles.

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BassCliff

 

[Guest]

Hi Mr. Bob Young,

Are there any advantages to this setup? It looks unnecessarily complicated (more failure points) for these simple, reliable motorcycles.

I was thinkin the same thing. Whats the point?

 

[BILLDIGIOIA]

Just questions and curiosity

Just questions and curiosity

You have one coil feeding two plugs and that while one cylinder is firing on a power stroke the other cylinder is wasting a spark near bottom dead center. So if you adapt your system, you would be splitting the firing signal between two coils firing two plugs, instead of one coil firing two plugs. And here is my question, given that the electrical system on a Suzuki is one step up from Lucas, the prince of darkness, will splitting that firing signal between two coils make it too weak to run either coil?

Second question, placing a coil on top of, or in very close proximity to your air cooled engine/cylinder head and directly connected to the engine vibration and heat, wouldn't that shorten the coil's life appreciably? Note that your coils are presently connected to the backbone and there is air movement around and below the coils and vibration is dampened by the frame.

 

[Suzuki_Don]

You have one coil feeding two plugs and that while one cylinder is firing on a power stroke the other cylinder is wasting a spark near bottom dead center.

The wasted spark is not at BDC (bottom dead centre). For instance a coil fires cylinders 1 and 4 and both of these pistons rise and fall together so there is no way that one can be at TDC and the other at BDC for the wasted spark. While one cylinder is on the compression stroke then its corresponding cylinder is on the exhaust stroke: i.e. #1 on compression then #4 on exhaust stroke.

The wasted spark is at TDC on the exhaust stroke of the other cylinder and this also helps reduce the emmissions going to the exhaust system. Any unburnt mixture gets cleaned up here as the wasted spark does it job on the exhaust stroke.

 

[BILLDIGIOIA]

I stand corrected and better informed.

 

[Suzuki_Don]

I stand corrected and better informed.

No Worries Bill. We are all learning something or other.

 

[Bob Young]

Coil over plug

Coil over plug

Thanks for the replys. An interesting comment was made regarding "air cooled" engines.The coil over plug conversion has been done successfully on Kawasaki in line fours and they may have been liquid cooled. The advantage is no plug wires; the igniter fires each plug (which has it's own coil). But I haven't used the coil over plug set up, so I'm not really sure how well it works, although the Kawasaki folks are pleased. There is a "hand made" wire harness and connectors that need to be built, but given the ability of most motorcycle modifications, shouldn't be hard to do.
But the possibility of an air cooled engine verses a liquid cooled may be a consideration. To me, the benefit of not having to replace the plugs wires and possibly the coils would be a good reason for this type of modification.
Just thinkin'........