charging system

[copperhead25]

Hello again, I have a '79 xs eleven special...on a recent ride, the battery discharged. After a recovery period it was fine. the battery is new and has been load tested OK. I hooked up an Ammeter/voltmeter combonation as recommended in Clymers for testing. While at idle everything is OK....14 volts and 6-8 amps. Upon acceleration, the amps drop to about 2 causing the battery drain I assume. The stator and field have continuity respectively but I dunno how to use my ohm meter to check exact resistance. Lights and fuses are OK....I welcome ideas and inspiration.....

[TopCatGr58]

Sounds like the Voltage Regulator may be faulty, but I'm not an electrical GURU! What you stated happens is opposite of what's supposed to happen!!! Should be about 12 volts and low amps at idle, but should increase to 14.5 V at 2+K RPM?!

The Ohmeter may have a scale you set, like Kohms, vs. Ohms, or it may be automatic/electronic. So either set it for OHMs, or just check the suspect circuits using the OHM setting, and it will read out in either OHMS or K-ohms! Just check the white wires against each other, all three, should be 0.4ohms +10%, at 68 degrees! Then check the field coil Brown to Green wires, should be 3.5ohms same tolerance!

Also, check the ground on the VR, clean the contacts, the VR grounds to the frame thru it's case/cover IIRC, check for corrosion and clean! Then Retest Volts at idle and reved!?

Then post back your findings, and I'm sure some Elect. Guru will chime in!
T.C.

[copperhead25]

follow up

Thanks for the info. Field and Stator test OK. Rectifier tested for continuity OFF the bikeas described in chapter 6 of the Yam shop manual.....

element d4 shows very slight continuity between b1 and b2
element d8 shows very slight continuity between g1 and b2

Other than that everything tested fine. Have not checked VR as described in manual as I need to put some more parts on the bike first....will keep you posted.

Anyone got a good lead on a VR that doesn't cost an arm and a leg????

[dbyers]

Partsnmore.com has one for 95.00. Ebay is always a good choice but you have to read the feedback section to make sure the person selling it has positive feedback. Good luck with the search.

[TopCatGr58]

Hey there Copperhead,

Well, again...NO ELECT. GURU HERE, but the Clymers states to take OHMETER measurements from the following groups! IT states that absolute-specific values are not possible/needed, just that you record your readings from each location/combo of wires with the test leads in ONE POLARITY. Then repeat with the leads in the OPPOSITE polarity! They should differ in values by NO LESS than a factor of 10!! If any of the elements is defective, the whole unit has to be replaced.

B1 and U
B1 and V
B1 and W
B1 and B2
U and G1
V and G1
W and G1
B and G1

Geezer was working on a replacement for the VR, not sure how it's going? HTH.
T.C.

[copperhead25]

continuing saga

Hello again.....I have run all the tests that I know to run and have taken the bike to my electrical gurus home for a healing session. We have not been able to find anything wrong other than what has been already stated. I have a replacement VR enroute.
I'm thinking this...I've made this too difficult....everything in the manuals on electrical testing starts with..."make sure you have a fully charged battery"....I placed the battery on the charger overnight prior to conducting tests. After I ride the beast 70 miles or so, the battery starts losing charge.....Any thoughts on me being an idiot and not replacing my battery.....

Remember.....KISS
Keep
It
Simple
Stupid

[skids]

Re: continuing saga

Charge it and then load-test it. It is the only way of checking it instead of just measuring a "skin charge."

Originally posted by copperhead25
I'm thinking this...I've made this too difficult....everything in the manuals on electrical testing starts with..."make sure you have a fully charged battery"....I placed the battery on the charger overnight prior to conducting tests. After I ride the beast 70 miles or so, the battery starts losing charge.....Any thoughts on me being an idiot and not replacing my battery.....

[tfm3]

Been doing a lot of VR's and batteries lately. VR replacement is good preventive maintenance anyway,so you didn't waste your money. Strongly recommend splurging on a good battery-there is a difference between brands.

[graybird78]

battery

not a electical guru. batteries are 12 volts. a fully charged battery should show 12.6 volts +. it is poss you have a shorted battery. meaning the plates shift inside it when you ride. when the bike sits and cools plates shift. alittle trick a guy showed me was to charge battery and use volt meter to check the individual cells in battery. most batteries have 6 cells. each cell should have 2volts. using volt meter put neg lead on batt-, poss lead attach peice of copper wire. now put end of wire in each cell starting at battery -. each cell should show 2 volt increments up to 12 volts. 1st should be about2 volts
2nd about 4 volts
3rd about 6volts
4th about8volts
5th about10 volts
6th about12 volts
any cell that doesn't show about a 2 volt increment is bad e.i #4 shows 6 volts. that cell is bad.
hope this helps.

[scoobes]

had the same problem with mine last week,went out on it the rev counter was sitting at 2 th revs but not the engine,got home swithed her off then the batt was dead.seat off tank off put another rec/reg unit on and it is ok.see if some one is close to you and swap there unit with yours just to eliminate if yours is faulty.