Charging issues

[AndreP]

Hello, 1990 k75 rt

Battery died toward the end of last season after being fine all year. It was a couple years old and a cheap one so I figured whatever it’s probably just an old battery. I put in another one I had lying around, everything is fine. Fast forward to this year and the bike won’t start. Bought a new battery this time (o’reily). After about a week the bike dies again and won’t start or run without a jump box attached. There has been no battery light lit this entire time. I did replace the monkey nuts to find the old ones pretty much disintegrated. The alternator is that aftermarket one that’s all over the internet (black one) and has different hookups than the stock, all installed by a PO. I thought there were just too many accessories originally (fog lights and flashing led brake lights- all installed by a PO). Anyways, the alternator isn’t charging the battery and as I’ve said I never got a dash light.

Here’s what I’ve done:
New battery (now dead)
New starter (from eme)
New starter relay (eme - I whacked the other one unstuck like 5x)
New monkey nuts (eme)
New transmission ground cable (eme)

I have a multimeter but do not know a lot about how to use it.
My thoughts are:
A wiring issue with the alternator or grounding issue
The two year old aftermarket alternator is caput already
Maybe my bulb in my dash is out?

Next week I plan on cleaning the ignition switches I guess since that’s what I’ve seen on here. Let me know if you guys think I should just buy another alternator or what. I really want to get back on the road this is prime RT riding climate I’m missing right now.

Thanks!

[AndreP]

https://www.partsgiant.com/p413690-wild-boar-alternator?m=29360281&srsltid=AfmBOoo2-fyEEKM0zRT7EPTX76FwmcRYsAlt-kKBsJmwwtEcgJKdh8FH8nY&gQT=2
This alternator

[frankenduck]

Does the charge warning lamp illuminate when the key is turned on but bike not started? It should. (Assuming there is some charge in the battery.)

If that bulb goes out then the alternator won't work.

[AndreP]

The lamp does not illuminate neither does the oil pressure warning lamp.
Are you saying if I replace the bulb the bins will charge again?

[frankenduck]

Both the teapot lamp (oil) and the charge lamp should illuminate with the key on, not running.

You can swap in a known working bulb from one of the other lights to see if that makes a difference. All of the other lights in the cluster use the same 168 bulb. (Except for the turn signal bulbs.)

[Laitch]

Both the teapot lamp (oil) . . .

The oil can icon spout would have been longer but there wasn't enough room on the instrument panel.

[frankenduck]

I got that joke from an auto site meme asking what the teapot light was for.

[AndreP]

I’m having trouble attaching pictures.
I replaced the bulb and holder with brand new parts. Now, with the key turned and ignition on, the charge battery and water lights are off. The oil light is on, however.
Do you think there could be a corroded wire leading up to the bulb? And if so how would I find it?

[AndreP]

I confirmed it’s a wiring issue by trying a working dash from my parts bike. Again, no light.

[Laitch]

As frankenduck has mentioned, the charge battery light is on when the ignition key is turned to On. The light is on because the battery isn’t being charged. The battery isn’t being charged because the engine isn’t running to operate the alternator to commence charging. If the engine is running but the charging light doesn’t light, that is happening because the wiring of the charging system could be somehow faulty if the battery light has been proven to operate.

As he also indicated, the oil light is on when the key is turned to On because the engine isn’t running to produce oil pressure.

The temperature light is off when the ignition key is turned to On because it only turns on when the engine overheats when running.

There are several videos on YouTube that explain how to use a multimeter to check engine electrical systems. Watch a few of them. You should prove by testing that the two year-old alternator is caput, not assume that it is, or you should take it to auto electrician for diagnosis.

Some of this could possibly be ground problems, as you have indicated. You could find them using a multimeter.

[daveson]

 The alternator is that aftermarket one that’s all over the internet (black one) and has different hookups than the stock, all installed by a PO.

This could be a problem.

With key on, engine off, the battery light gets power from the instrument cluster and earth from the alternator through the blue wire, so the light glows. With the engine running, the light gets power from the alternator through the blue wire, so with power on both sides, the light turns off.

Possibly the light isn't getting power, probably though it isn't getting earth. If you're not sure about a multimeter, a test light is much easier. Maybe unplug the instrument cluster multi plug and check for earth from the blue wire (pin 9) with the ignition on.

[frankenduck]

As frankenduck has mentioned, the charge battery light is on when the ignition key is turned to On. The light is on because the battery isn’t being charged. The battery isn’t being charged because the engine isn’t running to operate the alternator to commence charging. If the engine is running but the charging light doesn’t light, that is happening because the wiring of the charging system could be somehow faulty if the battery light has been proven to operate.

As he also indicated, the oil light is on when the key is turned to On because the engine isn’t running to produce oil pressure.

The temperature light is off when the ignition key is turned to On because it only turns on when the engine overheats when running.

There are several videos on YouTube that explain how to use a multimeter to check engine electrical systems. Watch a few of them. You should prove by testing that the two year-old alternator is caput, not assume that it is, or you should take it to auto electrician for diagnosis.

Some of this could possibly be ground problems, as you have indicated. You could find them using a multimeter.

The charge light has two inputs:

The bike's power level: GRN/BLK 12V from Fuse 1 (Switched) to the cluster pin 6

The alternator power level: BLU from the alternator (0V when not working, 12V when alternator working) to cluster pin 9.

When not running there's 12V across the bulb so the charge lamp illuminates. When running and alternator working there's 12V on both sides of the bulb so the voltage difference across the bulb is zero and the bulb goes out.

Check that the connector on the rear of the alternator is well seated. Next test for continuity between the blue wire of the alternator and pin 9 of the cluster connector.
 
Also make sure that the copper "foil" on each side of the bulb holder slot has not been folded under:

[AndreP]

SOLVED!

The blue wire connection was all shitty and weird. It had this extra piece on it I removed and plugged it in again and voila! The battery has 14.2 v at 2000 rpms!

Thanks for all the help guys! I’m slowly getting more comfortable using the multimeter. Electronics always scare me.

I’ll post some pics tonight