I bought this quad non-running a while back. It ended up having an idle jet clogged, so I replaced the carbs and it has run fantastic since. Until now.....

Details: I think this is an older 4 wheeler, its a hunting style with racks. It has an inline twin cylinder. It has 2 carbs (one feeding each intake), 2 exhausts (one coming from each cylinder head port), and two coils (one feeding each plug). It is a copy of an older Honda Rebel 250cc engine from what I have gathered through my research. Honda rebel parts look identical and fit the bike with no issues. It has a foot shift (one down, 4 up) just like a motorcycle. The reverse is cable pulled and the mechanism is located in the rear end. It has one cdi box that has the two separate plugs (6 total pins I believe) with the plugs with the rounded edges. It also has a 9 pin square connector going to another box similar to a cdi but it doesn't seem to be connected to the coils and I don't know what it does or where to get a replacement.

The problem: I first started getting intermittent no start and/or dying while riding conditions. They would go and come occasionally with no changes made to the bike. It finally started running very rough consistently.

The diagnosis: I diagnosed it as the passenger side plug not getting fire. I suspected the cdi, so it was replaced with one off ebay. Still no fire. I then suspected a coil and/or wire issue. I checked the wire and found a blockage. I traced it to the boot (for some reason a short would not show through the boot). So I ordered some new coils with wires. Still no fire. This whole time the drivers side will fire. So I took a black with yellow stripe and green wires off the driver coil and put them on the passenger side and it would then fire. So for some reason the passenger coil is not being told to fire. I traced the black with a yellow stripe back to the cdi box and check continuity and both coils showed good wiring. I checked both greens for grounds and no issue there either. I'm not for sure if this cdi I bought will even fire a second coil as most china bikes seem to be 1 cylinders now-a-days.

What's my next move?

 

I've never seen of of these quads. So I'm just guessing...

Look at the following link:

http://www.hondarebelforum.com/image...ng_diagram.jpg

Note in this Honda Rebel wiring diagram the 6 pin CDI (2 connector - 4 pins and 2 pins) has *two* outputs to drive the coils individually - both are yellow/black wires. This is quite different from the standard 6 pin CDI where the same connector has only one pin for the coil drive and *two* ground pins.

Recently there was a post from another two cylinder quad where both coils in parallel where driven from a single CDI output wire (from the same 6 pin CDI connector pattern). This is confusing to say the least...

I'm wondering if your original setup was one that needs separate outputs from a special CDI. If true, it makes sense that when you plug in a generic CDI with only one coil drive output you only get spark on one coil.

So what are the colors from the wiring harness on the CDI? Do you have two black/yellows?

Again, I really don't know. I'm just fishing for clues to the puzzle .

 

Right, the picture you posted is how mine is setup. Individual wires on individual pins running the two separate coils. I'm thinking the china CDI box I went to replace it with is for a single cylinder bike. I cannot find a 250 twin cdi box, but honda rebels CDIs are easy to locate. I may go with a genuine Honda part. I saw the other 250cc thread and it sounds like he may have a similar engine to mine.

 

I also have the nine pin unit that appears similar to a cdi but Im not sure of its purpose/function. Curious......

 

This is what it looks like. Mine is solid white, painted by me.

 

I've also seen twin cylinder wiring diagrams where the two coils are driven from a single CDI output wired in parallel. I would think this scheme wouldn't be optimum for a number of reasons, but since the wiring diagrams exist there is a possibility that it will work. If it were my quad I would try moving the second CDI output wire in the harness and tie it in parallel with the first. The see if you get spark in both cylinders...

 

Remote modules usually have nine pin connectors and they tie into the ignition system. But I've never seen one of these on a 250cc quad.

So what are the wire harness colors on this nine pin connector?

 

My remote module has a similar connector to this as well. It is located under the seat. This box is located up in the front near the cdi box and other ignition related items.

As for the colors, I will have to check and get back to you.

For the firing of the coils, if they fired off the same wire, that would mean they fired at the same time, and I know the pistons don't cycle together. You can tell by the way the motor runs that they fire the mixture 360 degrees from each other. I'm pretty confident the honda coil should fix the problem. But, time will tell.

 

Here's my alarm box and connector:

 

Here is the mystery box on the left, and the ebay replacement cdi on the right (noted to only be about 2/3 the size of the one I took off).

Looking at the connector on the mysterious box, the wires were:

Yellow
Red/yellow stripe
Green/blue stripe
Blue/red stripe
Middle pin was empty
Green
Green/blue stripe
Black/white stripe
Black

8 wires on a 9 pin square connector