PMA Problem - Stator still looks good but no voltage

[NorthParkMC]

A little help,
So this is a reoccurring issue I have had on my 82 xs650. I thought the problem was fixed but recently my charging system went out. I have about 1000 miles on the PMA and when the system went out i decided to replace the voltage reg (didnt know how to test it). So after replacing the voltage reg, i checked the charge at the battery and it was still not charging. I next checked the voltage at the 3 yellow wires. There is no charge coming from either of the wires, yet the continuity test checked out fine. I popped the stator out and inspected and cant find a break in the windings or the wires. The color also looks fine. It looks to me like the stator is okay, however it is not producing a charge.

Here is something that i suspect may be an issue. The magnetic field on the rotor seems weak. Is it possible for the rotor to loose charge this quickly and is there any way to test the strength. There is still a magnetic charge, it just feels noticeably weaker than when i first put it on the bike.

The bike ran for about 1000 miles just fine and one day the charging system just failed on me. I replaced the voltage reg and have the same setup that worked. The voltage reg has green wire grounded to the frame, and the red wire directly to the positive terminal of the battery.

I think a new rotor or the PMA runs about $100 on mikes. Im not sure if this is the same one that Hugh offers. I got my whole system from Hugh. Suggestions please. Thanks for your help. Happy Holidays!!!

 

[XSLeo]

Contact Hugh, It may still be under warranty. He has lots of experience with PMA's.
Leo

 

[NorthParkMC]

I have contacted him. Im sure with the holidays he may be backed up. This unfortunately is my 3rd PMA. Im thinking there's now way this one went out on me. I can't have that bad of luck. I was hoping maybe someone on here has had a similar problem and could tell me what to look for. Im skeptical about the strength of the rotor magnet. It feels weak. Wish there was someone around with a spare so I could test that theory without buying a new one.

 

[retiredgentleman]

Where did you buy the first 2 PMAs, and how long did they last? Did they have any warranty, or did you lose money on them?

Maybe its time to use a stock type alternator. The one on my bike has been very reliable.

 

[NorthParkMC]

All the parts have come from Hugh. the first one was faulty I believe. and the second one may have gotten shorted by a bad ground. Hugh helped me trouble shoot and by the 3rd one I had a complete working charging system. Like everyone says, it was much better than the stock system. I rode it for about 1000 miles and then recently something went out. The problem is when I took the stator out this time it looked fine. I cant spot any breaks in the coil and we tested the 3 yellow wires for continuity and they all checked out. When I test them for voltage with the bike running i get nothing.

 

[retiredgentleman]

You've had 3 PMAs fail, and you say that is "much better than the stock system". I can't follow that logic.

Suggest you continue to contact the seller of the PMAs, for assistance.

 

[NorthParkMC]

The output from the PMA is more than the output of the stock charging system, and it charges at idel unlike the stock. Obviously the system failing makes it not worth keeping

 

[NorthParkMC]

waiting on a response from Hughs Handbuilt. Ill let you know what happens.

 

[chizler62]

Checking voltage from the yellow wires is not telling. Just make sure each has a minimal amount of resistance and that none of the three have continuity with ground.
Completely unhook the Voltage/regulator and check for an open across the diodes. green thru the yellows and then red thru yellows then in reverse polarity and the reading should be opposed or simply go one way and not the other. Some good meters will have an actual diode selection and it'll just beep.

I have seen a few of these "JUNK....IMO" aftermarket PMA kits just simply have connectors that are under rated and melt. The spade itself has too much resistance and causes an abnormal amount of heat. Check all the connectors for yellowing and melting. Especially the 3 yellow leads connector coming off stator.

Another thing to check, in your case you would've prolly already seen it, is if the mag is slipping on the crank.

Is your Regulator/Rectifier placed out in the open where air can cool it?

If you honestly feel that the magnet has gone weak. I wouldn't replace it with another one of the same brand. That's a huge misstep in quality for a company to be selling that.

 

[barncat]

reviving an old thread...

got stranded out on the road the other day, knew it was electrical but nothing obviously wrong. got it home and isolated the problem to either the reg/rec or stator (it's a PMA capacitor setup, no battery). strong spark to both plugs with a battery hooked up when motor is kicked through.

i know how to wire a bike but i'm not an expert at meter diagnosis. the disconnected reg/rec shows about 30K ohms across green and all yellows, and the same across red and all yellows. 0 ohms for all when reversed. so i believe that means it's ok?

that would tend to leave the stator as the culprit. it was hard wired to the reg/rec, no obvious burned wiring, and everything is still mechanically sound with the mounting and rotor. resistance between the various combinations of the 3 wires is zero. continuity with ground would be a 0 ohms reading between any stator wire and ground correct? they all spec at infinity. anything else i should look for?

 

[XSLeo]

Infinity means no continuity. The reading from the yellow wires to ground should get this reading.
Ohms readings from each yellow wire to another yellow wires should have a small ohms reading. I'm not sure what the spec should be but the stock stator is .9 ohms.
When testing ohms this low you need to check the ohms of your test leads by touching the leads together. On one of my meters this test is .1 ohms, on the other it's .7 ohms.
This test ohms is subtracted from the reading you get from the yellow wires. As in using my .7 meter the wires test at 1.5 ohms, you subtract the .7 to get .8 ohms.
I have found the exact ohms isn't as important as they all read the same.
If two sets of wires read .7 and one reads .1 or 1.5, you have a bad stator.
Do these ohms readings on your lowest ohms scale. most digital meters this is the 200 ohms scale.
Leo

 

[barncat]

Leo- thanks for the advice. i have no formal instruction in multimeters...

just re-checked. there is no continuity with ground on any of the three stator wires. all spec at infinity (1).

the inherent resistance of the meter appears to be .1 ohms on the lowest 200 ohm scale. or i assume it's .1 ohms- there are two decimal places in the display at that setting and frankly i don't exactly how to interpret that.... it's an Etek digital multimeter.

resistance between the wires is then .1 or .2 ohms at lowest setting, within the variation that you get based on meter tip to wire contact. so theoretically the stator should be ok, but it's dead as a doornail in terms of spark to the plugs when kicked thru...

again, this is a PMA setup. should there be a brief flash of voltage when a stator wire is clipped to the meter and ground when the motor is kicked thru? there is none.