Charging system problem YY250T 244cc

[timk225]

My scooter has a charging system problem. It's a 2007 Jonway / YY250T / Viva MP250RO scooter. With the vertical cylinder 244 cc engine.

A friend of mine had it before me, and he replaced the battery with an Autocraft 9BS. A few days ago, I went to start it and the started just buzzed. I had been messing with the radio under the seat the night before, and when I lifted the seat, the radio lights were on, so I figured it was left on and drained the batery. I unplugged the plugs going to the radio, since I don't use it anyway, and took the battery to Advance Auto Parts to be 4 hour slow charged and tested. It tested good, with 12.51 volts and 173 CCA.

So I drove my scooter about 80 miles between last night and today, when all of a sudden I went to start it and the battery was low again! I got a jump start and drove it home, and by now even the radiator fan was running slow and the starter wouldn't even buzz when I tried it.

So clearly this thing isn't charging. I'm going to pull the body panels off and see what I can find out. I read on how to test the stator with an ohmmeter. I have done a lot of electronics work so this won't be hard.

Where is the stator located? Inside the right side engine cover? I'll follow the wires and see. Any common problems in this scooter's charging system, and can it be upgraded with high powered parts?

[timk225]

More news. I pulled the rear plastic body panels off and checked things out. I have the 6 wire voltage regulator shown on this page:

www.scrappydogscooters.com/CF250_Water_cooled_parts.html

Sixty bucks if I have to replace this 'ma! In the picture on their site, the wires go: yellow black yellow green yellow red. Mine is yellow green yellow red yellow black. Hope that's not critical!

Attachments:

[timk225]

Then, here's the 3 wire plug with the 3 yellow wires coming from the stator. I used my multimeter to test the resistance, pin to pin, and each one, compared to one of the other 2 pins, was in the 1.2 ohm to 1.3 ohm range. Each pin, tested to metal frame ground, showed about 9 ohms cold, and about 13 ohms hot, right after I had test run the engine.

Attachments:

[timk225]

And what is thing? A ballast resistor or something? It's bolted to the same metal plate as the voltage regulator. I tried doing a continuity test on it, and when I touched my meter probes to the pins, I'd get one little beep and no more. No steady beep after 5 minutes of trying. The connector fits kinda loosely.

Attachments:

[timk225]

Then I did a running voltage test. The discharged battery was showing 11.6 volts with everything turned off. I jump started the engine, and at idle (about 1500-1700 rpm) I'd see 12.5 volts across the battery terminals.

At 2500-3000 rpm, 12.6 volts.

At 4000-5000 rpm, 12.7 volts.

I never saw it get over 12.8, not even a little bit.

My automotive experience says a charging system should be around 13.5 volts depending on air temperature, mainly in the 13.2-13.8 volt range. Maybe a little higher, but 12.7 volts is definitely WRONG!

So what might be the problem? Is the stator shot? Is the voltage regulator not regulating? Any other possibilities?

What kind of multimeter testing can I do on the voltage regulator?

Also, the fuse box has 4 10 amp fuses in it, and none were blown. Just mentioning that to try and give complete information.

[nulldevice]

First check the charging system for poor connections. You may be charging from only two of the alternator legs.

Keep in mind these alternators have permanent magnets and are regulated differently from auto alternators. Since there are no field windings they are regulated with a shunt regulator that shorts excess amperage to ground in order to control the voltage in the system. As a consequence there is very little extra generation capacity in these scooters.

With that in mind, check the electrical load on the scooter. Are there high wattage headlight bulbs, high wattage tail light bulbs, electronic accessories added, or any other electrical load that isn't stock.

For example a pair of 55/60 watt headlight bulbs instead of the stock 35/35 watt bulbs, and you are in voltage deficit territory, especially at idle. If the cooling fan runs most of the time while riding you are in voltage deficit territory even at low to moderate road speeds.

Keep digging, let us know what you find.

[nulldevice]

Background information.
I have been struggling with the charging system and headlight brightness since I got my scooter. I found a fried regulator and replaced that. Further lack of charging was from a bad plug between the alternator and the regulator, and a second regulator fried on me. The third time I lost both headlights and fried a third regulator. There isn't extra capacity in the regulator either. I got tired of buying regulators at that point.

So, some digging on the Internet, study, and experiment I finally got a home made regulator that works really well. It only took four fried regulator builds before I got one to survive my experiments. Now came the balancing act.Too much load and the voltage will be too low. Too little load and my home built regulator would get too hot to touch from shunting the extra amperage to ground and would eventually burn out.

First step, remove the two ten watt LED headlights. Voltage was OK but the regulator ran too hot.
Next step, replace the 35/35 watt headlights with 55/65 watt H4 bulbs. Voltage was too low but the regulator was cold.
Next step, Replace incandescent tail light bulbs with LED bulbs. Voltage is good and regulator is slightly warm.

The voltage drops to 12-12.5 volts when the cooling fan comes on, but I put it on a manual switch and it only needs to be run maybe for one to two hours a hear, a few minutes at a time in stop and go traffic. Keeping the battery charged is not an issue. I got my electric system to the it ain't broke so I will stop fixing it point.

If you go this route, a permanently mounted volt meter is invaluable, and you can see what is happening with the volts as you drive. It also serves as a warning when electric things go south.

[timk225]

Yes, I was thinking of adding a volt meter also.

Here's more test results:

With the engine running, I pulled off the 3 pin plug going from the stator to the regulator. I set my multimeter to AC volts and tested from each of the 3 pins to frame ground. 2 of them showed 30-32 volts AC, and the 3rd, the one on the end, showed nothing. Does that mean 1 of the 3 phases in the stator is shot?

I pulled the stator out today and cleaned it all. It looked to be in good shape, no signs of anything burned or arcing or anything. I'm going to take it to some alternator shops tomorrow and see if they can tell me anything useful.

When the 3 pin stator plug was unplugged from the regulator, engine rpms would go up a few hundred, when I plugged it in, they'd drop back down a few hundred.

When riding, I do notice the fan is on an awful lot, even though it isn't needed. I used a laser temperature reader to take readings, and nothing was over 150 degrees, not even the cylinder. The muffler was hotter but that's all. The scooter has 2 taillights on whenever the engine is running, 2 big headlights, and 2 little headlights that I think are pretty useless. The gauge lights are always on with the engine also.

Auto parts stores around here have aftermarket fan switches that can be adjusted for the temperature they come on at, I could install one of those to reduce the amount of time the fan is on.

Could the Chinese regulator / rectifier be replaced with something better?

I read today about using the multimeter to test the diodes in the regulator, I'll do that tomorrow.

[timk225]

I took the stator to 2 alternator shops in the area to get their opinions on it. Both said the same thing, nothing appeared to be burnt, shorted, open circuit, or otherwise malfunctioning. The second shop had a friendly old guy doing my testing. Always trust a friendly old guy, they have been in the business for 40+ years and have seen it all. I even gave him a few bucks for his time and diagnosis.

So I'll reinstall the stator and order a regulator. That BETTER fix it!

And I'm going to add in a manual on/off switch for the cooling fan, it doesn't need to run anywhere near as much as it does.

[nulldevice]

What AC voltage do you get between the phases at your RPM test speeds?

Voltage between phase 1 & 2
Voltage between phase 1 & 3
Voltage between phase 2 & 3

[nulldevice]

If you are handy with a soldering iron, you can make your own rectifier/regulator unit for 10-20 dollars. That is essentially the only option for a three phase regulator/rectifier for these scooters.

[timk225]

No, I just bought a new regulator online at scrappydogscooters.com, it's the same 6 wire style as what I have. $60 bucks, and it BETTER be the problem!

I'll test the voltages tomorrow.

[justbuggin]

have you check the fuse inline with the small red wire to the battery

[timk225]

Yes it is good.

[timk225]

I reassembled the engine today, and started testing things. Using my multimeter set to ohms, and probing the red and black wires of the regulator with one lead, and the 3 yellow wires with the other lead, I was getting nothing for a reading, in any orientation of the leads.

I started up the engine, and at idle, with the multimeter on AC Volts, and testing the 3 yellow wires from the stator at their plug, any wire to any wire I was getting 34-35 volts.

I put the multimeter across the battery terminals (on DC Volts), and most of the time it was showing in the 13-14 volt range, then once the temperature gauge got to half way, I realized I had accidentally pulled a wire off the radiator sensor for the fan, so it wasn't coming on. I put it on, and with the fan running, voltage was in the high 12's.

So I'm guessing the regulator isn't regulating right, and I have one on the way from scrappydogscooters now, it should be here by tuesday.

Once I get this thing fixed, I'm putting in a manual switch to cut off the fan, it runs a lot even when the temp gauge is low.

[nulldevice]

Your alternator and regulator seem to be working normally. A new regulator won't change the voltages you get because the alternator just doesn't put out enough amps to maintain 13-14 volts when the fan is running.

With the manual switch on my scooter the only time I have to turn the fan on is on hot days when I have to sit and wait for a lot of traffic lights or for a couple minutes after I get off the freeway into stop and go traffic.

[leo]

Mar 14, 2012 16:22:01 GMT -5 timk225 said:

Where is the stator located?

bolted to the right side engine cover, inside the engine.
there are a number of things you need to deal with here.
you will need to remove the swing arm plate and the rear caliper among other things.
the caliper mounting bolts MUST NOT be interchanged.
the external oil line must be removed.
there are 3 oil bolts for this line, one right behind the starter, one on the stator cover, and one on the valve cover,
the valve cover and stator cover oil bolts MUST NOT be interchanged, they have different spray patterns and you will ruin your engine if you interchangs them.
the crank has an oil drive pin, a spring, and a metal bushing on the end where the stator cover mounts, DO NOT lose these parts.
make sure that the drive pin is installed and the spring and bushing slide into the crank and in place before remounting the cover.
the stator wires and pickup wires run through the same hole and pass through the same grommet.
this is apparently molded to fit the cover.
in other words you will need to cut the stator and pickup wires out of the grommet somehow and find a way to reseal them.
it appears that the stator and pickup was meant to be replaced as a unit.
be sure to take careful note on how the wires are routed inside the cover and follow that route exactly when reassembling.
remember, close tolerances and loose wires make for a bad day.
yeah, i've done this before.
can't you tell?

[timk225]

What? The valve cover and stator cover oil bolts have different holes / patterns? NEED PHOTOS QUICK, there's a 50/50 chance mine are in wrong!!!!! AAAAHHHHHHHHH!!!!!!!!!!

What size oil hole in each one?

Everything else, I had no problem with disassembly / reassembly.

I did not have to pull the swingarm or rear caliper.

Where is the oil pump in this engine? I assume it's down low in the crankcase. Oil goes out the big bolt on the front, up through the external tube, to the stator cover, and up to the valvetrain.

Why does it stop at the stator cover? What needs oiled in there that splash lubrication can't handle?

I'd also like to say that the rear suspension mounting is a real half assed design, even for the Chinese copycats. 2 casted in aluminum tabs on the front of the engine case, and THAT'S IT for swingarm mounting? Are those Chinese designers INSANE?!?!?!?! There needs to be some massive steel plates in there somewhere!!!!!

[leo]

Mar 17, 2012 22:47:46 GMT -5 timk225 said:

What? The valve cover and stator cover oil bolts have different holes / patterns? NEED PHOTOS QUICK, there's a 50/50 chance mine are in wrong!!!!! AAAAHHHHHHHHH!!!!!!!!!!

relax.
i will check mine in a few hours when it gets daylight and i will let you know.

Where is the oil pump in this engine?

if i'm not mistaken it's right behind the water pump, it's what drives it.
the water pump has a slot and the oil pump has a tab that mate together when you reassemble the stator cover.

Why does it stop at the stator cover? What needs oiled in there that splash lubrication can't handle?

this is where the crank journals and rod bearing gets its oil from.
remember the spring and bushing?
oil goes from the external line, through the oil bolt and spring, inside the crank, to the journal.

I'd also like to say that the rear suspension mounting is a real half assed design, even for the Chinese copycats. 2 casted in aluminum tabs on the front of the engine case, and THAT'S IT for swingarm mounting? Are those Chinese designers INSANE?!?!?!?! There needs to be some massive steel plates in there somewhere!!!!!

the CVT housing bears the majority of the load, probably all of it.
if it wasn't for the caliper and muffler mounts, and of course the rear wheel spacers, you probably could ride your scoot without the plate

[timk225]

I see, the external oil line feeds the bearings. Doesn't this engine have ball bearings on the crank and needle bearings on the rod? They need less oil than conventional automotive engine bearings. Well, whatever. I want to make sure I have those bolts in there right.

On the end of my crankshaft, the spring and bushing never moved, and I did not even touch them at all. So they should be ok.

The rear suspension needs to be looked at from a physics point of view. The rear shocks / springs and CVT housing may take a lot of the vertical / suspension load, but if the swingarm pivot on the front of the engine is the only connecting point, then every single time you hit the gas, hit the brakes, go over a huge bump, etc, the entire load is going through those 2 casted in aluminum tabs! All these forces are conspiring to try to rip the entire engine / rear wheel assembly out of the scooter. I sure as hell wouldn't put all this load on the front of the engine case, which is probably a cheap ass Chinese casting in the first place.

I have a real problem with the front suspension too, it's designed like this is a 20 inch bicycle! WEAK!!! But that's a story for another topic.

[leo]

well.
i've been parroting the service manual for the helix/ elite in regards to a few things, one of them being the oil bolts.
the helix manual specfically states do not interchange the valve cover and stator cover bolts or engine damage could result.
i removed both of mine to eyeball the differences between the 2, i cannot find any.

the only difference i've seen was the 2 holes that go into the banjo fitting are slightly larger on one of them.

[nulldevice]

Mar 18, 2012 13:10:26 GMT -5 @leo said:

well.
i've been parroting the service manual for the helix/ elite in regards to a few things, one of them being the oil bolts.
the helix manual specfically states do not interchange the valve cover and stator cover bolts or engine damage could result.
i removed both of mine to eyeball the differences between the 2, i cannot find any.

the only difference i've seen was the 2 holes that go into the banjo fitting are slightly larger on one of them.

The bolts are different, I noticed the hole size difference too while repairing my oil leak, but -- the hole sizes will determine how the flow is distributed between the crank shaft and the valve train .I took a guess and put the bolt with the large holes into the crankshaft port. I figured if I guessed wrong it is a lot easier to redo the valve train than it is to change out the crank, rod. and associated bearings.

The information looked for is WHICH SIZE GOES WHERE?

[timk225]

The 2 oiling bolts are indeed different. Same length and thread size, but the oil holes are way bigger in one then the other. And of course, mine were in backwards, but I fixed that real quick. The big hole bolt is oiling the crankshaft bearings now.

I stopped by the local Advance Auto Parts today, and picked up a switch to use in wiring an on/off circuit for the fan, since its excessive running may have been the problem all along. The switch had "Made in China" on it. I opened up the box, flipped the switch twice, and... it fell apart. Typical Chinese quality, I just had to laugh at it.

[timk225]

I went back and got a different switch today. Still Made in China, but it seems to work, it's a totally different design.

I wired the switch into the fan circuit, so I can break the circuit and thus make the fan unable to turn on without the switch being closed.

I ran the wires down under the handlebars and found that a ledge in the right side brake hose was a great place to mount the switch with a solid base, so I taped it in there. I road tested it and so far it does its job.

I did another voltmeter test today, and even with the fan disabled, I never got over 13 volts, with the engine revved up or not. Hmmm.. The SIXTY DOLLAR regulator I got better fix it! I think it'll be here tomorrow.

I borrowed my Dad's battery charger, and I'm keeping the battery charged with it so I can still ride it some.

[bikerdude]

Just a thought, you could have a shorted cell on your battery, you can connect your volt meter to GND and poke the positive right into each cell hole to the conductive plates inside, each should, give approx 2 volts each cell or more with no load on battery.

[timk225]

I tried the new voltage regulator / rectifier today. It showed pretty much the same voltages, although slightly improved. It still wasn't getting over 13 volts even at 5000 rpm, and that's with the radiator fan turned off.

I put in a cutout switch to keep the fan off when not needed.

So it may be the damn stator after all.

I was over at (all right why is the sco--ter pro--essors site name deleted? Don't be a phucking idiot about competition from another site) website, where they had more extensive tests, and the stator passed every test except resistance to ground. Ohms between each of the 3 yellow leads, to another yellow lead was 1.5 ohms, but I was also showing 6 ohms from each yellow wire to a frame ground, and 16 ohms to the engine block. With the engine revved up a bit, on AC voltage from each yellow wire to another, it was a bit over 60 volts. And 34-35 at idle.

DAMMIT DAMMIT DAMMIT!!!!!!!

Although by keeping the fan off when not needed, and only using the low beam headlights, the battery was still showing 12.7 volts at rest with the key and engine turned off. After I put about 50 miles of driving on it.

[leo]

unplug the autochoke BEFORE you jump to conclusions.
the autochoke is run directly from the stator and will give the false impression the stator is grounded.

yes, the OEM switches on my bike were, well, less than A-1 quality.
ALL of them have broken.
i found i only need 4.
turn signal switch, got this at radio shack, 2 position center off.
"ignition switch" double pole double throw.
start switch and horn switch, both of these are momentary contact push on switches.
none of them are certified waterproof so i covered them with bicycle innertube.
i spray the crap out of them with WD-40.

i'm thinking about a headlight switch but i really don't need it.

[timk225]

Autochoke? I'm guessing a wire plugs into the carburetor somewhere for that, I'll look for it tomorrow. I sure hope that is why I'm reading resistance in that test!

I was at a local motorcycle shop today, and they had a 4000 mile 2002 Honda Reflex 250 for $1250 for sale. I looked all over it and my scooter is obviously a copy of it, with only minor changes. It didn't have the vertical cylinder 244cc engine, I don't know if it was a 257 or more likely a genuine Honda engine.

[leo]

Mar 23, 2012 22:12:56 GMT -5 timk225 said:

Autochoke? I'm guessing a wire plugs into the carburetor somewhere for that, I'll look for it tomorrow.

yeah, right next to the thermostat housing.
mine has the two wires to the autochoke and the temp sending unit wire.
the other end has a 2 prong connector and the wire that connects to the stator.
unplug the one that plugs into the stator.

I sure hope that is why I'm reading resistance in that test!

if you didn't unplug the autochoke then you will get a reading from each stator wire to ground making it appear the stator is grounded.

[leo]

Mar 14, 2012 17:40:11 GMT -5 timk225 said:

And what is thing? A ballast resistor or something? It's bolted to the same metal plate as the voltage regulator. I tried doing a continuity test on it, and when I touched my meter probes to the pins, I'd get one little beep and no more. No steady beep after 5 minutes of trying. The connector fits kinda loosely.

most likely an isolation diode.
you will get a low resistance in one direction and a very high reading when you reverse the meter leads.
unplug the diode connector before testing the resistance.

i have no idea why this is included on some bikes and not others.
mine has no such device.
the red R/R wire on my bike goes to the battery through a fuse.