Running Voltage Too Low, Now Too High

Thanks for the breakdown! I will check the ground wire for the headlight bulb as well as try pulling the indicator bulb. I replaced my gauge housing a short while back and could have potentially muddled something up in the process there. Still need to pull the switch out of the housing and inspect, but this seems like a likely culprit.

As far as bulbs go, I don't have any LEDs, just standard.

 

do you have the headlight pigtail extention? part 23 in this drawing I do not think the main harness connector actualy fits properly to headlight.
I think the pigtail was made to be scaraficial so the main harness was/is not dammaged due to heat.
https://www.partzilla.com/catalog/yamaha/motorcycle/1982/xj650j/headlight

 

Pulled the headlight switch apart, everything appeared in working order but took a couple quick pictures.

The headlight is https://www.amazon.com/Wagner-Lighting-H6024-BriteLite-Sealed/dp/B000C90MNE

I do believe I have the noted pig-tail extension, it seems to run from the bulb to under my gas tank so I believe I will have to pull it to check the far end. Odd side I've noticed is that the highbeam flicker seems to happen exclusively when at the ~1,600RPM range. Above and below it doesn't occur.

Planning to pull indicator bulb and seeing if it fixes.

 

EDit i went and pulled a headlight or 2 and the connector you have does look like a pigtail should be 4 inches long and have a white connector to connect to main harness.


switch contacts look good any wire strands on other side poking out where they should not be?

if you take off the pigtail and look into it you will see a tab push tab with a tiny sscrew driver or large sewing needle and you should be able to remove metal contact for ground on both ends clean them inspect connector bodies to see if the show signs of melting. also check the main harness connector for melting.
clean contacts a little dielectric grease and reassemble

 

Oh I see what you mean. No apparent melting but I'll pull the contacts and try cleaning them up and re-assembling

 

Cleaned and re-assembled the pig tail as well as pulled the highbeam indicator bulb (it is standard not LED).

At ~1,600RPM the highbeam does not come on but the low beam flickers and dims.

Could it be that this is still an overvoltage issue? I'm still waiting for a more reliable multimeter in the mail, but my questionable meter is showing low 15's voltage at the battery.

 

15 volts at the battery points towards the voltage regulator being bad that is typical of an over voltage situation. Sometimes doing the test you see in the book of measuring the diodes doesn't necessarily show a bad voltage regulator. I have the same problem with the over-voltage put it in VR in the problem went away.

Bring the RPM up to 3000 and see if the voltage goes higher. The both of you are looking for is in the high for is 14 point eight volts.
You can try another meter but eventually you have to just learn to trust your equipment.

 

I recently changed out my R/R unit. With the original I was seeing voltage up to 17V, with a used one I got off eBay I'm seeing voltages in the mid 15's.

It sounded like having a bad R/R is rare, I would assume more so to have 2 in a row. Do you think I should pick up a third?

 

maybe get a new one

 

Plugged in a 3rd R/R unit today and saw the same results, 15V at the battery and the same highbeam flicker at ~1,600RPM (which remains on until the revs go above or below).

Either I'm very unlucky with R/Rs or I need to consider that maybe there's something I'm missing. Will be inspecting other elements of the charging system and seeing if there is anything out of place. This is turning into quite the headscratcher.

 

Found someone with a similar issue on a different bike: https://www.reddit.com/r/Fixxit/comments/38mv11/2008_fjr1300_my_fjr_is_intermittently_deciding_to/

It sounds like their problem was bad grounding but unfortunately their solution was to take it in for repair. At least it gives me a good idea of what I should be looking for.

 

The slightly high voltage I would check this again. Measure the voltage at the Brown and Red wire on the regulator connector, and IMHO there are likely quite a few XJ's running around with close to 15V.

The flickering low beam light seems to be occurring right at the point where the AC Generator is providing all the power and beginning to charge the battery. I am not sure that means much but I would try a different bulb as the xenon bulb may not be compatible or is more sensitive to the AC component of the AC generator.

Does the high beam flicker like the low beam when selected?

With low beam selected probe the black return line at the headlight H4 connector in reference to battery negative. You would need to see at least 2 to 3 volts for the high beam indicator bulb to be visible. If you see the 2 to 3 volts then either the ground is inadequate or there is excessive current (xenon bulb).