Regulator Stator Or Battery Problem By ridecheap (Read 1,999 times)

[ridecheap]

I have the 250b 257cc Yahma clone engine.

I got a new battery about 3 months ago and I have to keep charging it up all the time because it dies and jumping it.

I just got a new battery today with much better CCA and AH will post more details about that later.

My old battery tested with multimeter First TEST:

Just sitting there: 12.2 DC Volts -

Turning the Key: 11.6 DC Volts -

Turning the engine on and reeving it: 11.8 to 11.9 DC Volts

Here is my regulator tested: I tested by sticking the multimeter black wire to the frame of the bike and testing the plug on the top each wire connected. The regulator is putting out 5.4 Volts DC current hooked up and running.




I then unplugged the three yellow regulator plug and started the engine today.


With black miltimeter wire grounded the frame and testing with the red multimeter wire I get these results. The bottom prong unplugged I get 20 AC current that changes when revving. The two right and left prongs I get 0 AC.


I then tested the multimeter on each prong while running.

Inside the three wire prong to the stator I tested while running:

Bottom wire with Right wire: .2 AC

Bottom Wire with left wire: 20.-40. AC

left wire with right wire: .1 AC



Do you think the stator is shot or the regulator??? Or do you think the battery was shot when I got it and could never hold a charge now.The regulator seems to be putting out 5.4 volts DC and when uplugged the stator seems to putting 20 to 40 when reving it AC power to the plug.

[ridecheap]

New battery inside that is fully charged. I put it in and revved the engine its not charging up staying at 11.9 DC Volts. It must be the stator or regulator. I am thinking its the stator?? Any ideas.

[tvnacman]

Well your in the same place, we need to know what the ac voltage output from the stator is. If the stator is connected to the regulator it throws off the voltage measurements.

John

[cruiser]

Here's an excellent troubleshooting guide for the charging system from our tech files:

thescooterprofessor.proboards.com/index.cgi?board=gele&action=display&thread=1140

[JR]

Great Pictures and labeling Ridecheap and I'll for sure keep it for reference. All your AC readings and the output of the R/R indicate a bad stator. Your DC voltage had no change with the scooter revved up.

From what I see you've now tested the 3 yellows from the stator and just like in the link Cruiser gave you with the scooter revved to 5k RPM you should read 60Vac+ when testing each leg.

I like to simply label the 3 yellows 1 , 2 and 3 and then test each leg like this

1 to 2
1 to 3
2 to 3

They have to be very close to equal as this scooter has a 18-coil stator with 3 seperate coil banks or phases.

Do make sure the 3 yellows are going to the engine and if you do not read 60Vac+ on all 3 legs then it's time to replace the stator.

JR

[JR]

The three yellow wires are the AC feeds for the regulator/rectifier. They should test out about 70v AC with some RPMs. If one of them reads very low or nothing then the stator is toast. I test them in series and you can read how I do it right here. I know some folks disagree with me on my testing method but I've found it works well.

Read more: scooterdoc.proboards.com/index.cgi?board=250cc&action=display&thread=7102&page=1#ixzz2AmdrAuPE

He's exactly right folks who know how to really test the stator know his testing method is wrong and also 60Vac + is listed because the voltage depends on the RPM, at it's peak it's around 100 Vac.

My friend if you don't read the output voltages like I stated before then the stator is toast.

JR

[ridecheap]

Oct 29, 2012 20:46:50 GMT -6 JR said:

Great Pictures and labeling Ridecheap and I'll for sure keep it for reference. All your AC readings and the output of the R/R indicate a bad stator. Your DC voltage had no change with the scooter revved up.

From what I see you've now tested the 3 yellows from the stator and just like in the link Cruiser gave you with the scooter revved to 5k RPM you should read 60Vac+ when testing each leg.

I like to simply label the 3 yellows 1 , 2 and 3 and then test each leg like this

1 to 2
1 to 3
2 to 3

They have to be very close to equal as this scooter has a 18-coil stator with 3 seperate coil banks or phases.

Do make sure the 3 yellows are going to the engine and if you do not read 60Vac+ on all 3 legs then it's time to replace the stator.

JR

Getting nowhere near 60 AC


These are real readings with a shot stator..

Postive the stator is TOAST. I put these results down from the unplugged on the stator side of the connector in AC.

Bottom wire with Right wire: .2 AC

Bottom Wire with left wire: 20.-40. AC

left wire with right wire: .1 AC

The only wire putting out any AC when unplugged is the bottom wire. The only charge it takes is the bottom to the left wire and its only 20 AC.


My stator is shot big time


With the plug pluged into the regulator and testing the three wires in DC its only putting out 5.4 DC volts on two of the three wires... I think the regulator is working fine because it is converting the AC to DC.

[tvnacman]

I would agree the stator is no good.

John

[alleyoop]

I also agree the stator is toast
Alleyoop

[JR]

We have a engine manual to tear her down and get her going.

Good going.

JR