:: Yamaha Virago XV Forums That Rock!!! » Tech Help » Charging Question!(SOLVED)

#1:  Charging Question!(SOLVED) Author: jovanavichs Post Posted: Fri Jun 18, 2010 12:38 am

Alright, I got an electrical question for you all. Last week, after work, went to start the bike and the bike cranked slow. So got the jump box on it and it started. Rode home, lights are not as bright as they are supposed to be. So I get home thinking the battery just crapped out on me and I get a new one. Everything was great for like 4 days. Then same thing, weak battery. Got the jump box again and bike started. Got the DVOM and checked R/R output. Less than battery voltage. 3000RPM took me .2V higher. So I rode the bike home thinking I was gonna be stranded. While going home, some moron in the fast lane was tearing it up so I punched it around him. Took the bike to 6K. Tach started freaking out. Fluctuation from 2 to 10K. All the while the bike behaving more or less normally. No power surges, no power decrease. Get home, check the white stator wires for power and resistance. I got about 20-21VAC from the stator. Resistance is between .6-1.1Ohm. I hook up to VDC and find that the voltage is now up again to 13.8V. There are 4 wires beside the 3 white wires going in. There is a red wire which is the main converted power out which goes to the battery. There is my ground wire. There is a wire that takes a detour to the diode pack and then there is an ignition switch wire.

Any clues to what may or may not be going out on the bike as to the charging system? I thought that maybe it was the regulator. But now I am leaning maybe to a bad ground or possibly a bad diode. The wonderful schematics do not tell me which part of the diodes in the diode pack to test.

I tried my best to include all the testing I have done. Without any specs on the diode pack, I would like to know if its good or bad instead of shotgunning away without any reason. I am fairly adept to testing electrical if I know what I am supposed to be looking for.

Thanks everyone for reading and offering any ideas and/or clues.

*EDIT* as a side note, this all seemed to have kicked off when my headlight relay bit the dust. I had "a" relay, not the "right" relay. Regardless it worked except whenever the key was on the headlight was on. When the battery went dead the second time, I disconnected the headlight bulb from within the headlight bucket.

Last edited by jovanavichs on Mon Jun 28, 2010 12:37 am; edited 1 time in total

#2:  Re: Charging Question! Author: eaglebeak Post Posted: Fri Jun 18, 2010 12:48 am

Do the frame-grounding modification first because that is the major issue that plagues all Viragos in all forms of electrical issues from ignition, lights, and charging systems - then we can go from there if that doesn't fix the problem.

#3:  Re: Charging Question! Author: jovanavichs Post Posted: Fri Jun 18, 2010 1:02 am

Done eons ago. Sorry I didnt post that with the main post. That was done like 3 batteries ago. Battery to frame, R/R to frame mods were done. Nice clean fat wires were used with clean frame grounding points.

#4:  Re: Charging Question! Author: eaglebeak Post Posted: Fri Jun 18, 2010 1:17 am

Seeing the frame ground should be OK, I'd go back and do the AC voltage test with the stator's output unplugged from the RR module. If you don't have a throttle lock, have someone maintain an engine rpm somewhere around 2k to 2.5K then use your meter to measure between each possible pair combination of the three white stator output wires (three different meaurements). If each of those measurements isn't within about plus or minus 5% of each other, then you probably have a stator problem. If the three unloaded AC output measurements are about the same, the next step will be to use the ohms scale on your meter to do a resistance check on the three RR input points from the stator while the stator cable remains disconnected. (let us know if you need the point measurement and correct reading table).

#5:  Re: Charging Question! Author: jovanavichs Post Posted: Mon Jun 28, 2010 12:36 am

Alright! Update on the electrical concern here. This problem seemed to be coming and going here. For several days the charging system would hang around 13.2V idle and about 13.6V at 3K. Then for no reason, the bike would have a low battery when I went to start it up. So what I did is completely eliminate the connector from the Regulator to the bike main harness. I took both positive and ground from the regulator and ran them direct to the battery. I have re-ran my main battery/chassis ground with a 6g wire. Almost all the battery positive and battery negative wires have been either modified, piggy-backed, or completely replaced. As to date, no problems yet.

Stator wires still have 20-21VAC from all wires.
Stator wires still have .6 to 1.1ohms resistance.

The biggest unknown is still the diode pack. No information exists on an internal schematic for it. No where on the internet shows anything but replacements for the diode pack.

The headlight relay has a white wire that goes to the diode pack. I grounded the black wire to manually turn on and off the headlight. I just disconnected the white wire to the diode pack with no ill effects.

As of right now, I am gonna mark this one solved even though I did nothing to remedy this problem. I still believe that this problem is in the diode pack but until I can get more information to either prove or disprove this, I am not gonna go any further.

#6:   Author: coalstoves Post Posted: Mon Jun 28, 2010 12:47 am

Study the wiring diagrams and look at what systems the diode pack works with you'll see it has nothing to do with charging.

Many folks myself included tend to look for the one thing we don’t understand and focus on it as the root of the problem .
I have posted over and over the procedure for trouble shooting the battery & charging system do a search you'll find it pretty easy .

On the same lines search diode pack here and your likely to find replacing it has never done anybody any good .

Inatall the correct replacement for the headlight Relay !

#7:  Re: Charging Question!(SOLVED) Author: jovanavichs Post Posted: Mon Jun 28, 2010 1:17 am

Cause my manual doesnt specify the colors as in other wire schematics, the one wire, which I believe is the yellow wire heads right to the diode pack from the regulator connector. White wire from the headlight relay also heads to this diode pack.

If you have a Clymer manual handy, page 259 has the schematic for my bike.

Even though I am running a 920 engine in my bike, the bikes electrical all stayed 750.

Thanks coal, I have read your previous posts and yours are what helped me in knowing more about these electrical systems. Thats why I am left to believe that this problem is somewhere in that diode pack. There are 7 wires on a 9 pin connector going there. I know diodes are one way electrical valves and if one is allowing power to go somewhere where it aint supposed to be, I believe that may be part of my problem. But right now with everything behaving normally for the moment, I cant diagnose it any further. As for the headlamp relay, I am gonna leave it. Daytime riding I am gonna have it off as not to stress these charging systems any further. If I need to do any night riding, I can always flip a switch and turn em on.

#8:   Author: coalstoves Post Posted: Mon Jun 28, 2010 1:44 am

I looked at that I keep forget the 1st gen use a diffrent RR still I'd be looking more at the headlight relay that you said is a non OEM replacement . Check your state laws regarding headlights on bikes, here in Pa they are mandatory Day or Night

Last edited by coalstoves on Mon Jun 28, 2010 1:50 am; edited 2 times in total

#9:  Re: Charging Question!(SOLVED) Author: jovanavichs Post Posted: Mon Jun 28, 2010 1:47 am

Here in NM the law wants em on day or night also, but with the amount of other law breakers out here, they keep busy with people speeding, reckless driving and such, I am on the low end of broken laws here.

#10:  Re: Charging Question!(SOLVED) Author: jovanavichs Post Posted: Mon Jun 28, 2010 2:00 am

Thanks for the link, however, the one that I needed, was the only one not in color. Its just as the one in my book is. Which is all good. I am grateful you had the link. If I can find some more information on the diode pack, I will surely share what I have learned. I am thinking an Ebay find on a cheapy and tearing into it. Find which diodes go where and such. » Tech Help » Charging Question!(SOLVED)

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