Electrical issue

Hey guys!

So new problem with my bike. Well it's been an intermittent problem up til now.

Battery isn't charging (brand new). When I check the voltage after starting the bike I'm only seeing 11.75v at the battery? When I roll on the throttle to get the RPMs up i see no change. Turn signals don't flash at idle but if I get the RPM up enough they start to.

Read someplace this might be a symptom of a bad regulator/rectifier. As it happened I had a brand new one that I had never installed (bought it when debugging another issue and it wasn't the problem at the time). New one is in but same issue.

Wondering if anyone has any suggestions for next steps or ideas what it might be? Alternator maybe?

 

Alternator brushes go bad in these older bikes.
How savvy are you with a voltometer?Let's start with some questions.
•What type of battery? (Wet/Dry)
•Did you charge the battery before use to the manu spec?
•What is the Cold Voltage of the Battery? (12.5V is what you are shooting for)

Now on to the harder part, testing.
You are right in you reading that power goes through a big loop before it gets back the the battery, but unless everything is perfect and brand new, seeing 12V at the battery at idle and 14V above 2000 rpm is what we can hope for.
So test. (You may need a helper)
•Connect your voltometer to your battery, check Cold Voltage (may need to be charged first).
•Start bike and check voltage above 2000 Rpm at the battery.
•(Optional) swap out your reg/rec and retest.
•(Optional) test ohm Resistance. Let's number the wires in this fashion. Top line 1-4, bottom line 5-8. The top line should be 3 white wires.
Unplug the reg/rec and test these connections (first number being your negative lead) record all Values.
5-1 (red-white)
5-2
5-3
1-7
2-7
3-7
Now reverse your leads
1-5
2-5
3-5
7-1
7-2
7-3
What you should find is that each of these number sets will have a high and low value (about 10x greater) for example 5-1 may read .25 and 1-5 will read 2.5 like this.
You must be very careful not to cross any of these terminals and short them out.
•(Optional) test your existing reg/rec, now to do this you really need two voltometers but we can get away with the one. Find the black and green wires (number 7/8 in the group). Place your -negative cable into the black wire, and your +positive cable into the green wire, be careful not to short the connectors as this will fry your reg/rec. With the bike running and above 2000rpm this should read 14.2-14.8V.

•Final thing is if all of these things work the way they should, swap out your lights for LEDs and pretend these never was a charging problem.

 

Oh sorry, I missed the part where you said you put the new reg/rec in and have the same issue. So ignore all of the checking if the regulator is bad stuff.
Go for the alternator.
Check the leads from the alternator.
Check resistance between the three white wires (1-2, 1-3, 2-3) it should be low, like .5 ohms.
Check the green and brown wire (4-8) it should be high like 4 or 5 ohms.
Make sure your checking the alternator side, not the reg/rec side.
If all else fails, open the cover and check out your brushes by eye.

Sorry for the info overload but I just ran through this a few weeks ago.

 

open up the alternator check the brush lenght and clean the copper rings with a hard eraser then clean off with eeectric contact spray

in this link you will find test specs and possible causes
The Ultimate Relay, Switch, Sensor, and Diodes Guide

way down at the bottom


"If your charging voltages are too low, suspect the alternator brushes first, then perform the alternator stator and rotor checks as described in the Alternator Section."

 

Dry battery.

About 12.24v when off. Haven't charged it again since was turning it in and off yesterday.

The 11.75v is what I see once it is on and no change when rolling up the RPM over 2k.

Opened the alternator. One brush is definitely a bit more work than the other but both are well above the "replace" line.

Cleaned the rotor as recommended as couldn't even tell it was copper.

When checking ohms, I set the multimeter to 200k Ohms (tried a couple other settings as well). But when touching the copper on the rotor, nothing. When checking the white wires (Haven't checked the colored ones yet), nothing. Not sure if I'm doing something wrong Or if my rotor and what not is just fully shot.

 

Resistance should be set to 20 or 0.00. at 200k ohms you will only be testing a large device. When I get home I'll send a photo of my multimeter setting.
As far as the battery it seems all good.
After you cleaned the alternator did you run another test?

 

If your voltage isn't increasing when you increase the rpms, your system isn't charging. The 11.75v shows you're running off of the battery, AND it's already under 12v, so you're gonna drain it.

 

Yes I tested again after cleaning and no change.

That was what I figured as far as what I was seeing hog. Thanks for confirming.

I believe I tried it with my OHMs set for 20 as well. But will check again when I get the chance. May be a few days or til the weekend. Unfortunately the bike isn't stored here at my house. Makes tinkering a long process.

 

Hey Jim.....I'm just south of Utica, NY......where are you?

 

About 15 min south if syracuse. Bike is currently in binghamton.

 

I'm gonna send a private message to your inbox. Check there----

 

Rule number 1 when using a DMM... always start the process by touching the two leads together to verify zero ohms (or very close) is displayed.
Rule number 2... if not using auto ranging, select the lowest possible scale that exceeds the expected measurement to improve accuracy. Switch to a higher scale if no reading is obtained. Repeat rule number one if changing scales.

 

And if all else fails, I'll be back in Binghamton for Christmas.

 

Thanks for all the help. I'll let you know how i make out when i get time to mess around with it again.