Lynn,

This quad he describes sounds just like my set up.....Mine is the 2005 Yamoto 250 4x2 Utility Quad. I have the single CDI with 2 rounded corner plugs (4 pins / 2 pins). I'm still not getting fire on either plug either.

01ssreda4,

Is your a Yamoto 250 by chance? (it's a Kawasaki Bayou clone as best I can tell)....blue in color with hauling racks on the front and rear....twin cylinder, dual exhaust.

Question for you on yours: Can you please have a look at your left handlebar switch assy (start/kill/lights). Take a look at the connector and let me know if it is a 9-pin square plug containing only 7 wires that are male type pins. I would really appreciate it. This may help in my search for a replacement switch assy as mine is messed up internally and I've not been able to find a replacement with the correct plug after a couple months now of searching.

Sounds like we have similar issues here although I am not getting spark on either plug. I'm going to keep a lookout on your thread and maybe with any luck, we can help each other out here.

Roger

 

Wow. There is so much I don't know...

I need to think about the wire colors for the mystery box (which you posted a couple posts after this...). Let me do research and see if I can find anything....

As far as the dual cylinders firing 360 degrees apart I don't think this is an issue. Even the standard chinese one cylinder CDI fires every revolution just before top dead center. On a four stroke this means there is also a meaningless spark generated near the top of the exhaust stroke, which of course does nothing good or bad. But it makes the design of the ignition system much easier, so that is why it is done. Some refer to this as the "wasted spark" design .

So a dual cylinder 4 stroke could ignite the fuel in each cylinder 1 revolution apart (360 degrees) - with an extra spark near the top of the exhaust stroke in each cylinder - without problems. Thus a standard chinese CDI might work when driving two coils since it will fire on *every* revolution.

I hope that makes sense...

 

As a clarification, I was meaning the two didn't fire simultaneously, at least on the power stroke anyway. Since they do run separate triggers wires, my thinking was that this is done to offset the power strokes. Meaning one coil fires one revolution and the other on the second revolution, alternating of course for whichever cylinder in on its power stroke. And seeing as it takes 2 crank revolutions to complete all 4 strokes it made sense in my head. This would be much like a standard modern day automotive engine. However, I am aware of instances where multiple un-needed sparks may be done, mainly for emissions in automobiles so I do not rule out that either. Remember, this is a Honda clone, it is identical down to tolerances i would bet. Simply copying Hondas design for a CDI would remain simple. Everything Honda 250 Rebel (engine/electronics) bolts right to this bike. That is a fantastic source for parts as this bike is hard to locate but Honda rebels are not.

To RA, if you could please snap a few pics of your engine, I can directly tell you if ours are a match. If so, as stated, it is not a bayou engine clone but rather a Honda Rebel 250 clone (motorcycle). I can show in detail the handlebar controls as the bike is currently disassembled. I also have located a parts source that has some remaining inventory for this bike. Does yours look like the pic posted earlier in this thread?

 

No. I'm not talking about multiple spark plug firings near TDC on the *power stroke*. I'm talking about the spark plug firing *once* on *every* stroke near TDC - including on the exhaust stroke. So each cylinder fires near the top of the compression stroke (full of fuel air mixture) and goes bang (making power), and each cylinder also fires at the top of the exhaust stroke (the other near TDC position on a four stroke engine) and does absolutely nothing. There's nothing to ignite and nothing to burn. No gain, no loss... Well, except there is some gain in the simplicity of design. Fire the plug every revolution no matter what, and it will work even if half the sparks are totally wasted on the non combustible exhaust stream....

Since the timing trigger wire to the CDI comes off the crankshaft, and happens once per revolution, there is no information available to the CDI as to which cylinder is at the top of the compression stroke, or at the top of the exhaust stroke. One revolution of the crankshaft is the same as any other. To get compression stroke versus exhaust stroke information you have to have some sort of input from the camshaft position (which spins at 1/2 the crankshaft speed and therefore can conceivably have this info).

Does it make sense what I'm saying? Or perhaps I'm misunderstanding your thoughts .

 

No I gotcha. I'm just a car guy so I can over-think these little engines sometimes. But if what you are saying is correct, I should be able to trigger both coils off the same CDI pin and it should run. However, it begs common sense, why did they not do this from the factory? Why use separate pins? And, would I burn up a single cylinder cdi by attempting to drive two coils at once?

 

01ssreda4,

What I have exactly matches the one in your picture best I can tell. Although, your's is in much better condition it seems..

Here are a couple pics of mine.

I had a pic of the handlebar control and it's plug, but can't find it....I'll have to go take some more pics today and will post later.

 

Okay, I got some new pics of the engine, CDI, left bar switch assy plug to compare. But I am 99% that we have the same type quads here. The first 2 are of course the CDI box. Pic #3 is the left switch assy plug. Pic#4 is the quad side of the left switch assy. Pic#5 is the right side of the engine. The CDI has CM250 right on it, so that pretty much confirms what you said. I ordered a CM250 CDI and am hoping that'll fix my problem.....no spark on either plug.

I'll keep an eye on your thread in case we have the same fix. Here's the link to my thread:
http://forums.atvconnection.com/chin...-no-spark.html

 

Indeed, we do have the same quad. Whatever technical pictures you need I can get you.

 

Do you have the same type connector for your left handlebar switch? I've searched 'til the end of the internet (about 2 dozen different "Chinese Part" suppliers) and cannot find that switch assy with the type connector that I have.

 

Yep, same connector. I have the switch disassembled at the moment as I was verifying that my no run condition was not a faulty kill switch.