Electrical problems on gy6 50cc 139qmb

[mjordan2186]

Hi all. First and foremost, I'm Mike. I'm from Florida and thanks in advance for all your help.

I have a basic 50cc Chinese scooter. Gy6 50cc 139qmb.

I've blown a few headlights and tail lights. I've checked the voltage regulator on a good scooter and it's good. The stator from my good scooter had an acv output from the stators red wire of ~140acv at idle. That scooter electrical system has been consistent and hasn't blown any bulbs. The voltage regulator output on that good scooter stays at 13-15dcv output even with the 140acv input.

My other scooter (Icebear), has a good regulator, as tested on the good scooter, but every stator ive tested on it has an erratic acv output, flashing in and out on my multimeter ranging from 0-180+acv.

The known good regulator is having erratic dcv output exceeding 18dcv, and blows bulbs occasionally, only the headlight or tail light so far.

Does anybody know what can be causing this erratic behavior?

I have continuity on white yellow and green wires on the regulator as well as all wires on the stator and I'm pretty sure I've got continuity on the red wire on the regulator too.

Again, erratic acv output from stator is causing the regulator dcv output to be erratic ranging from 0-18+dcv output but the regulator behaves perfect on my other good scooter.

Can the acv output from my stator be getting bounced back through the wire causing unstable fluctuations?

I'm thinking about just replacing the whole wire harness for about $60, but I was wondering if anybody has some advice, input, or has an experience like this where they found a solution.

Lmk, and thanks in advance.

[snaker]

Visually inspect and meter out the stators to make sure they are the same configuration.

The stator type and the RR type must match.

[GrumpyUnk]

My take is that output is flaky or erratic when there are either poor connections, bad insulation allowing shorts/cross connects, or bad conductors that make/break contact. If the stator output is erratic, and it is a new to you stator or a replacement, it is possible for internal shorts that make/break contact to add/subtract windings that are being fluxed by the magnetic field.
So ... bad wires/connectors/grounds/rust/corrosion or bad stator. The magnet on the flywheel generally does not change unless things are loose mechanically.
The voltage I remember on one wire was in the mid-20's, with perhaps a high in the 40's at higher rpms. One wire had more voltage... one less. Nothing over 50 as I recall. Measured to chassis ground(engine block).
If you have a poor ground or bad connections, 'unusual' things can happen.
tom

[mjordan2186]

Thanks for your replies. I know the R/R worked on my alternate scooter. And I even tested that scooters stator on the Icebear with the R/R that just worked with it. Same erratic results.

I tested the original stator, which I replaced to try to remedy flickering lights, but it again produced the same erratic results.

So, I believe the stator and R/R to be compatible.

Th difference between full wave and half wave is confusing to me, and the stator, brand new, doesn't specify whether it's full wave or half. It's an 8 pole with no ground wire if that means anything. Again, the parts swapping test working on one scooter but same erratic results on the other is what sticks out to me.

I'm going to conclude it to likely be faulty wiring, be it bad connections or damaged wires or corrosion.

There's a brand new wiring harness on Amazon, Redcap brand, that looks to be the exact type I need. I'm going to order it and replace the wiring harness and let you guys know my results.

Thanks for your help.

[snaker]

Do the harness wires terminate at the same places on all your stators?
A half wave incorporates ground at the lighting coil and is really more of a dual circuit setup.
A full wave does not incorporate ground at the lighting coil, only in the RR.

Meter the two outputs to each other and to the stator plate.
What happens?

[deano]

Jul 9, 2024 16:46:05 GMT -5 mjordan2186 said:

Thanks for your replies. I know the R/R worked on my alternate scooter. And I even tested that scooters stator on the Icebear with the R/R that just worked with it. Same erratic results.

I tested the original stator, which I replaced to try to remedy flickering lights, but it again produced the same erratic results.

So, I believe the stator and R/R to be compatible.

Th difference between full wave and half wave is confusing to me, and the stator, brand new, doesn't specify whether it's full wave or half. It's an 8 pole with no ground wire if that means anything. Again, the parts swapping test working on one scooter but same erratic results on the other is what sticks out to me.

I'm going to conclude it to likely be faulty wiring, be it bad connections or damaged wires or corrosion.

There's a brand new wiring harness on Amazon, Redcap brand, that looks to be the exact type I need. I'm going to order it and replace the wiring harness and let you guys know my results.

Thanks for your help.

Did you solve this? I'm having similar issues, stator just seems to be blowing bulbs for fun and not charging the battery

[FrankenMech]

Maybe try fixing the bad engine to frame ground.

[deano]

Is there any way of identifying where these grounds are?

[FrankenMech]

Mark I eyeball. Usually an engine bolt to a frame bolt with a larger gauge wire like the starter wires. Remember the engine moves in the frame so they have to be flexible. There are a number of threads on the subject.

[FrankenMech]

I will explain this again...

There are 5 grounds on a scoot:

1- A micro thin ground wire in the wire harness, worthless for a general ground but is sometimes used for clearance lights, stop lights, turn signals, usually interconnected to ground #2, etc.
2- The frame ground used as a general ground and sometimes interconnected with ground #1.
3- The stator ground on some systems, a light duty ground for the stator.
4- The engine block to frame ground, a heavy duty battery cable thick ground for the starter current.

5- The battery to frame ground, usually piss poor.

When ground #4 breaks/corrodes or is left disconnected the starter current will often fry the #3 ground wire and connectors. This often causes poor starter performance or no starter at all. This will also cause the stator and regulator to go 'crazy' causing all sorts of problems like burning out bulbs, no spark, etc. These problems can appear intermittent also.

When replacing or repairing ground #4 I will use braided triple #12 AWG fine stranded silicone insulated wire solidly crimped into ring terminals using silicone dielectric grease to prevent corrosion in the crimp (with heat shrink tubing to limit flexure at the terminal) AND on the ring terminals solidly bolted to very clean areas on the engine and frame. I leave plenty of slack for engine movement in the frame and I try to eliminate any flexing of the wire at the crimp terminals themselves. The wire I use is available for battery wires on RC car batteries. As part of the repairs I check the frame ground where the regulator is bolted to the frame and coat it with silicone dielectric grease. I also check the battery to frame ground point and treat it the same way. The scoot frame is the high current ground for the starter circuit. The OEM manufacturers do not manufacture scoots with a proper frame ground because the crap brittle wire and connections they use will usually last through the warranty period (if any). I leave the user to find and repair any other burned or damaged ground points. I have explained how to make solid properly crimped and protected electrical connections before.