We have a 2007 Kawasaki Prairie 360 4X4 that runs extremely rough ( spits and spudders etc) at 1/2 Idle. At first, we thought
that perhaps it was in limp mode, however it WILL go into 4 wheel drive (its not suppose to if its in limp mode). We have been working
on this for over 3 months now and have yet to figure out the problem & we are desperate for help. I spent two weeks talking via emails
to a tv tech with over 25 years experience and still can’t pinpoint the problem. I would appreciate any suggestions or ideas any of you might have, short
of pushing this thing off a cliff!!

Background: Prior to this issue that we are having now, the machine had been running perfectly fine. UNTIL our last trip riding it my 4wheel drive stopped working after a day of riding.
Upon further inspection we figured out it was the 4x4 rocker switch that needed replaced & also the 4x4 actuator. I replaced that with new parts and it was fine. Ran fine. No issues.
No rough idle. The machine sat for about 24hrs before I was able to put everything back together. JUST prior to putting it back together, we tested it one more time to make sure all
was running fine and the 4wheel drive worked….. That is where all the problems started. The machine starts with no issue, but runs at very rough idle at 1/2 throttle (Video posted below)

Below is what we have done so far:
1. Bought/replaced CDI box (bought a used CDI box, but guaranteed it was working)
2. Bought/replaced speed sensor.
3. Bought/replaced 4x4 rocker switch
4. Bought/replaced 4x4 actuator.
5. New K&N filter
6. New Plug
7. Cleaned carburetor
8. Reset Belt multiple times ( but still flashes & wont go out)
9. We installed a spark plug tester: with the machine running/idling the spark is continuous and fine..HOWEVER as soon as you rev it up to 1/2 rpm the spark breaks down and the light starts flashing on the spark plug tester. This should rule out any issues that I could possibly have with the carb.

~ All the fuses check out fine.
~ Battery is fully charged.
~ All the wiring is good as far as I can see.
~ The belt cover switch is on the right position.
~ It goes into gear fine.
~ tried running it with the regulator disconnected -still runs rough
~ removed Drive Belt Failure Detecting Switch to test -still runs rough
~ disconnected The Reverse Position switch- still runs rough
~ disconnected Green Wire to ignitor- still runs rough
( during all these test the belt light still flashes continuously and runs the same way at 1/2 throttle & above)

The last thing Im considering replacing is the Ignitor and perhaps buying another CDI box ( since the 1st one we bought was used). It was also suggested that it could have jumped timing, however this does not make any sense since its starts fine, no rattling and it was completely running fine prior to us taking it apart to fix the 4x4 switch and actuator.

CLICK HERE TO VIEW VIDEO OF MACHINE!

 

Okay, a few questions. Does this happen only when warm or cold as well? Now based on this statement below I have a few thoughts:

HOWEVER as soon as you rev it up to 1/2 rpm the spark breaks down and the light starts flashing on the spark plug tester.

Let's say it is attributable to spark. You have already replaced CDI and it might be possible that it is a bad used CDI. I have only known them to either work or not but anything is possible. No let's look at 2 other items that impact spark. Your coil might be weak and when asked to provide more spark (at higher RPM), it fails. These are cheap to replace. The other area I know could fail would be the pickup coil (in the stator housing). You can ohm that out to see where it stands. If borderline it could be working at idle but failing at higher RPM's I've had Bayou's with no spark situations fixed by replacing a pickup coil.

Timing is easy to check so it is worth a shot. I have seen tight valves cause this too but it would be strange to "happen overnight"

Hope this helps.