Yamaha YTM200EK Battery voltage while engine is running (Is it charging or not?)

[eBoyDog]

I working on my headlight and tail light problem (they don't work when the engine is running) but I put my volt meter on the battery while the engine was running and found that I there isn't any increase in voltage while the engine is running. Now being familiar with other small engines that have a magneto and voltage regulator, typically one should see an slight increase in voltage but my Yamaha isn't showing such. Basically what I seeing with mine is that the battery is not charging when the engine is running.

The voltage stays the same regardless of engine idling or at a higher RPM, now I was expecting something in excess of 12 volts but the voltage stays the same around 12.3 to as high as 13.1 after I disconnect the battery charger but there is no change in voltage when the engine is running or not.

I have the manual for this trike and unless I'm missing something I find very little in diagnosing voltage charging issues, I'm assuming that I either have a bad regulator or the magneto coil charger is bad. I found a few tidbits here pointing out that it's common for the regulator to go bad. I have been tracing wiring, all so far appears good, no blown fuses or such. I have not tapped in the electrical to check voltages with the engine is running but that's my next step but given the fact that we are getting our first snow, I'm more interested in getting the trike out in the snow rather than sitting in the garage tracing wires.....

Can anyone offer more insight in what a proper operating electrical system on a Yamaha should be like? One thing I would like to ask too, once the engine is running, does that supply power to the lights which if the magneto is bad, that might explain my no light situation but if it runs though the regulator first, that also would explain no lights.

[emmie357]

I'm not sure about a lot of your questions... but one common problem with these trikes is that when you put the key to the "light" position, the trike dies. That feature is meant to run the light with the trike off. For the light to be on while riding, then engine should be running, and you should use the thumb switch (on the kill switch cluster) to turn the lights on. Lots of people overlook that after they see the "light" marking on the key switch...

More to your question... When I rev my engine, the light gets brighter, so I assume voltage is increasing. And the lights should work while the engine is running even with the battery disconnected.

Hopefully this helps. I've seen a few people overlook the thumb switch.

[eBoyDog]

I'm not sure about a lot of your questions... but one common problem with these trikes is that when you put the key to the "light" position, the trike dies. That feature is meant to run the light with the trike off. For the light to be on while riding, then engine should be running, and you should use the thumb switch (on the kill switch cluster) to turn the lights on. Lots of people overlook that after they see the "light" marking on the key switch...

More to your question... When I rev my engine, the light gets brighter, so I assume voltage is increasing. And the lights should work while the engine is running even with the battery disconnected.

Hopefully this helps. I've seen a few people overlook the thumb switch.

Understood, my issue is that regardless of the left handlebar light switch position, the headlight never works when the engine is running nor does the taillight work when the engine is running. When I turn the keyswitch to the light postion, yes the engine dies but the headlight comes on in both the hi and low beam postion. Also I checked the taillight and it has a good bulb and no issue with the fuse.

[emmie357]

Download the Clymer manual here:
http://www.oscarmayer.net/atc/manuals/

and look at page 195, if you have a multimeter (you can pick one up cheap) it tells you how to test the system. If the lighting coil is good, then check the wiring diagram and trace the wires to see if there is a bad connection.

Hope that helps.

[muthey]

on the ytm200 ek the light selection runs off of battery, but otherwise the lights always run off the lighting coil. If your charging coil was bad the trike wouldn't run so I would bet it is your voltage regulator. I would check the lighting coil and replace the voltage regulator.

[barnett468]

I working on my headlight and tail light problem (they don't work when the engine is running) but I put my volt meter on the battery while the engine was running and found that I there isn't any increase in voltage while the engine is running. Basically what I seeing with mine is that the battery is not charging when the engine is running. there is no change in voltage when the engine is running or not.

Can anyone offer more insight in what a proper operating electrical system on a Yamaha should be like?

Just like a car, plus around 1/3 to 3/4 volt at idle to around plus 1 1/2 - 2 1/2 volts at around 2000 rpm if your battery is good.

[eBoyDog]

on the ytm200 ek the light selection runs off of battery, but otherwise the lights always run off the lighting coil. If your charging coil was bad the trike wouldn't run so I would bet it is your voltage regulator. I would check the lighting coil and replace the voltage regulator.

That's what I thought that if the charging coil was bad, the engine wouldn't run unless the ignition is running off the coil. I suspect the prior owner fried the regulator and lighting coil as he described always jumping it off his truck battery to get it started since the battery was bad and the pull starter cord was broke. Then again if what he said was true, something must have been generating power to the ignition coil. First thing I did was get a new battery and while I have fixed the pull starter, I'm not able to pull start it as I'm limited due a physical disability so the electric starter is the only way I have to start it.

On a good note I had a blast yesterday in the snow with it, including having a little refresher on on just how fast one can take a corner too tightly and too fast.... I became a little too top heavy and kinda turned the trike over. Good news is I didn't hurt myself and second my 12 year old son witnessed it so I explained I did that on purpose to show him how NOT to drive it.

But back on topic, All my testing so far shows both the regulator and lighting coil being good but the regulator I get no continuity across any of the lines but my wire colors are faded and I'm not sure if I'm testing the right wires on the lighting coil lines. <edit> I thought the coils bad but I was checking the wrong wires - after trimming the black sheath a found the correct ones which are not part of the big plug but the two individual wires that come out of the stator.

[barnett468]

All my testing so far shows both the regulator and lighting coil being bad, I get no continuity across any of the lines but my wire colors are faded and I'm not sure if I'm testing the right wires on the lighting coil lines.

if you scrape or sand thre plastic on the wire a little you should see the color better

put some wd40 on it if you want and that might also bring out the color slightly.

check the wires from the coil for voltage while it's running.

[eBoyDog]

After trying 3 used regulators only to find all three were already bad, I found a bigger regulator/rectifer off a YFM225 that I picked up off ebay for a total of $7.50 shipped! After sorting out and adopting it to the YTM200, im now charging so thats all good.

Now my headlights and tail light still dont work which must be a wiring problem as I have tested both lighting and ignition coils aand they are good, I really thought it was a regulator problem but now that's ruled out. Given my headlight works when the key ignition is in the "Light" position I know the headlight works and the left hand light switch controls the light properly when the key is in the light position so it's has to be a wiring problem or at the extreme the ignition key switch since the power to the headlight circuit goes though the key switch. I have a brand new key switch on another trike that im going to try after walking though the wiring again.

Anyone have any other ideas?

Not sure if anyone has used a rectifer regulator that didn't belong on their trike but I found after studing it though the Internet that while the ytm200 has two wire coming off the stator and most newer engines have 3, I simply connected 2 of the 3 and left the third wire unconnected. On the yfm regulator the wire colors were even the same as the older ytm's but it had a eXtra brown wire which just a extra 12+ source for the newer atv's extra power requirements (left it unconnected too). I was very lucky to get what appears a yfm regulator that appears new and unused, the catch was that someone had cut the plug off it.