Recent Posts  By   (Read times)

2009 Kymco Agility 125, 12,000 km

On my drive home last week I came to a stop and noticed a sudden drop in my idle. The engine did not die, but it was pretty close. I kept the revs up while at the stop. Everything off idle is normal and it drives fine. Prior to this, the idle was normal. Seemed like a sudden change. It was raining during the 45 minute ride, but I've had it worse weather without issues.

This morning I started it up and it has the normal high idle (auto-choke works). But, after the warm up, I pulled out and it died at the next stop I made. Still had a low idle.

I have never done any adjustment to the carb or anything else on the engine. New plug ~2,000km ago, though the original plug still looked fine. New air filter around the same time.

Wondering if a carb adjustment is in order? Or valve adjustment? Could a bad auto-choke be causing this? Just seems weird that it happened all of a sudden instead of a gradual change.

Any info would be appreciated!

Sounds good! I didn't think it would be too big of a deal, just wanted to check. JR, those numbers I gave were at idle; I forgot to see how it responded to varying RPM. It could be I just checked it before the RPMs dropped down after the startup.

I'll keep the auto choke on the white wire. It seemed to do the job just fine, the engine settled down to a nice idle.

Best part of this upgrade is how steady the charging voltage is...it was sitting at around 14.2 VDC is wouldn't vary at any RPM! The battery was still charging so it may be more, I'll keep an eye on it.

Great sounds good! Yeah, I have no idea why they have it wired up the way they do (grounding the trigger wire).

I'll disconnect and the rest will be easy. I went through all the wiring yesterday to make sure there weren't any surprises when it came to the re-wire; this was the only one.

Have a make a run to get some wire, and I am still waiting on some connectors from digikey. Then I'll be able to get this project done with!

Thanks for the help!

I guess I should have been more succinct with my last post. I understand completely how the kill wire is wired and works, but the issue was the existing connection of the trigger wire circuit to the ignition switch.

If you look at the wiring diagram you will see that the L/Y wire (highlighted in cyan) from the trigger coil is wired to the CDI AND the N.C. terminal of the ignition switch. This grounds the trigger circuit when the key is off.

The N.C. terminal on the ignition switch is what I want to use for my kill switch, but it is already occupied and I don't know if connecting to it (without disconnecting the trigger wire from the ignition switch) will cause any problems.

I hope that makes more sense now.

That's good to hear! That will simplify the install of the new AC CDI a bit. All I will have to do is hook up the AC power wire from the stator, and disconnect the B/L wire from the CDI plug (which was originally used for DC power on the DC CDI).

Thanks!

Getting ready for some rewiring on the 11 pole upgrade and DC-to-AC CDI conversion. Quick question about the kill switch.

With the existing setup (DC CDI), the kill switch functions by grounding the PICKUP COIL TERMINAL (TRIGGER WIRE) on the CDI.

The AC CDI has a terminal devoted to the kill switch (ground terminal to kill). But, I was wondering: Will grounding the TRIGGER WIRE with the AC CDI still result in killing the ignition?

If it does, then it will save me some rewiring because the circuitry to ground the TRIGGER WIRE already exists, and I can just leave the kill switch terminal on the AC CDI disconnected.

I could swear I ran across something on the forums that said it would, but I can't seem to find it again...

Before I respond to your entire post/instructions, I think I need to gain a better understanding how the stator/flywheel/pickup coil work together. It seems I am confused with some terminology and how the engine timing is accomplished.



So I was using "Trigger Coil" and "Pickup Coil" interchangeably because I thought they were the same thing, but from the sounds of it they are two separate components....? I thought trigger/pickup coil was referring to the coil mounted outside of the flywheel which sends a signal to the CDI when the trigger/pickup magnet (which is mounted on the OD of the flywheel) passes by it

It sounds like you are saying the "Trigger Coil" is a coil on the stator, and the "Pickup Coil" is the externally mounted coil to signal to the CDI. Is this correct? I've looked at the Kymco 8 pole stator and all the coils look the same to me...

My understanding was this: the stator simply supplies AC power to the R/R and CDI (in Kymcos case, just the R/R, which gives us DC for the CDI). The flywheel has a pickup magnet mounted on it so that when it passes by the pickup coil, the CDI gets a signal at that point of the cranks rotation (TDC). The signal tells the CDI that the engine is at TDC (or close to it), and the CDI adjusts the timing based off the engine speed.

As far as the stator having any influence on timing, I don't see it. In between fires, the capacitors in the CDI are charged via the stator, but rotating the stator's mounting position will only change what point in time the CDI is charged (in the AC CDI case). I'm curious, but I doubt it takes one full rev (in between fires) to charge the CDI. If it does take exactly one full rev (8 magnets passing over the CDI charging coil), then the position of the stator must be precise...but still, this has no effect on timing, just charging for the CDI.

What really drives it home for me is to think about the DC CDI setup. First, the CDI receives constant power (DC) for charging the capacitors, thus the mounting location of the stator has no effect on the power supply to the CDI. Second, from just looking at how everything is wired up, the only communication with the CDI is power (DC from the R/R) and the pickup coil...nothing from the stator. This tells me timing is only controlled by the relationship between the pickup magnet and the pickup coil.

Basically, I just need to know how it is possible to retard/advance the timing by rotating the mountain location of the stator. I am missing something. The only way I see to retard/advance the timing is to move the location of the pickup magnet that is mounted on the flywheel. In my case, I am using the original flywheel with the new 11 pole stator, so I don't foresee having any timing issues.

Obviously you have encountered this problem before and rotating the stator was the solution, so I just want to know why. I really appreciate all the help! I always like to learn!