Twin Spark Plug Cylinder Head Prototype!

Hi. Actually, I'm glad you dug up that old thread.
Well, the twin plug head will be available soon. Right now I'm making the stage 2 heads which are lower compression than the first series of heads I made. So, now those heads will be called the stage 1 heads. I've decided to make the twin plug head, a twin plug version of the stage 2 head. Once that head design is in production, it will be called the stage 3 head. If twin plugs are used, it will be able to safely operate at the highest actual compression. There are some, like Arrow motorized cycles, who are running extreme engines that require even lower compression cylinder head due to the amount of "supercharging" those engines have from the use of highly advanced intake and exhaust systems. But instead of making a third single plug design head with even lower compression, I thought it would be better to simply add another spark plug. This additional plug will hasten the completion of the burning of the fuel mixture, thus preventing the deadly detonation.
I'm a little unsure about what kind of variations of this twin plug head I should make...
I certainly want to make some heads that actually have three spark plug holes; two for spark plugs and one for a compression release. One would go right on my bike as soon as it's ready!LOL
I'm kinda guessing about this part though; Most people probably won't want a head with three holes, so I think most of them will be twin hole designs, so either you run one spark plug and a compression release, or two spark plugs and no compression release.
Well, anyway, that's my current plan of what will come next.
I've got a ebay listing for the stage 2 heads. There is a image of the combustion chamber, which will be the same shape that the stage 3 head will have.
Thanks for your interest in my products!
-Fred

Hi everybody.
I've received a few requests for a wiring diagram for the twin spark plug head that will become available soon from CR Machine.
I'll try to get some pics of my simple installation, but the wiring diagram is really the most important info. I've been using a DC fired CDI to power the coil/coils.
I have found that a single CDI unit can reliably run twin coils. The coils I use are ones you would find for a small scooter, not the original equipment units we get with our China girl kits.

Hope it's helpful
-Fred

Ah hah!
Yeah, that's kinda funny. It's partly true, indeed.
I've got so much work in the shop machining, it takes a while to cover all the bases. Actually, I was hoping an electrically inclined person here on the forum would put something nice together. I've been thinking about it myself too. The one annoying problem that I have not been successful in solving, is obtaining the appropriate electrical plugs to fit the CDI. What I had to do was break off the white plastic housing and solder wires directly to the CDI. It works fine I guess, but it looks a little low tech.
Well, if worse comes to worse, and people want me to make turnkey kits, which allow you to simply plug the wires in, I can make up a few units and sell them on ebay. No problem. I already have two of the CDI units in stock, just for that possibility.

-Fred

Hi. Well, I don't know any particulars about this CDI, except that it is a DC fired unit. It is a common unit which I've seen sold by several vendors on ebay. Take a look at the picture of it, and I'm sure you will spot the identical one if you search for scooter CDI's on ebay. There is a number of coils that should work fine as well. To be honest, I'm not an electrical expert, like some on this forum, so you won't be able to rely on me for tip top support in this area. You have a picture of the CDI and the schematic. I hope that is good enough for now.

I will try a three hole cylinder head design, but I just don't know if that is going to stay. All these holes will eliminate some of the cooling fins; I'm a little concerned about that. It is a possibility that the twin plug head will only have two holes, so if you want to run the compression release (which I am not making right now), you will have to run just one spark plug.

-Fred

At last, the production twin spark plug head is here!

Well, we've been talking about it for a while, and now they are finally coming off the line!
Within a couple days, I'll have some available. I will start a thread in the swap shop, with details on what they will cost, availability and such.
I've tested it, and sure enough, it works excellent. The bike wasn't detonating at all when I was running the single plug version, so it really is not improving MY performance, but if the engine was tricked out to the max it would probably save it from detonation.
The compression release works really well as a rear brake. Sounds just like a big truck using the jake brake!
I've included a few images of my bike, showing the components for running the twin ignition. Earlier in this thread, I put up an image of the schematic. I'm working on full ignition kits, but with this information, you will be able to build your own.
Hope you like it!
-Fred

Hi Ivan
Hold on now.. Decompression valves have been used in two stoke bikes for many years. They aren't very common now, but they used to be common on dirt bikes of the past. I've been enjoying increased braking ability by using it. It's just the plain truth; I'm not making this up! It sounds just like a jake brake, and it helps slow the bike down. Not by a wee little amount, but by a significant amount you can really feel. I have a simple coaster brake in the rear, and just a small drum brake in the front. The addition of the decompression valve is allowing me to stop twice as fast. Now, I can leave the coaster brake just for emergencies.

-Fred

Hmm, well ok.
I really like how it helps me stop, and it gets attention, like a horn!
-Fred