IS this the Alternator bearings

Yoda · Nov 29, 2019

At 2300 RPM with the bike in Neutral and clutch in or clutch out or in gear there is a loud noise in the motor , or so it seemed. I used a stethoscope and placed it at the rear of the engine . Just normal engine sound. I placed it at the front of the Alternator and heard a slight rumbling, knocking sound. I placed it at the rear of the Alternator and it sounded way worse and loud and like it was coming apart. I also had a slight headlight flicker at 2300 RPM. Does this sound like a bad rear Alternator bearing ? I took the Alternator out but you can't tell if it's bad or not by just spinning the shaft.

UNCLEJOHN · Dec 1, 2019

THATS WHAT HAPPENS WHEN YOU PUT THAT "SPECIAL INVISABLE " OIL YOU USE !! :surprise::laugh::laugh:>

Pigeon Roost · Nov 30, 2019

Do we know the model year of this bike. Mass/spring ADG or mass/viscous ADG?

Larry! Great to see you are posting again!

prs

GLblinded · Nov 30, 2019

Did you open it up? Find anything bad inside?

Bluecyclone · Nov 30, 2019

Here’s what a bad ADG sounds like

LarryM · Nov 30, 2019

Bluecyclone said:
Here’s what a bad ADG sounds like

Good post. That really shows the difference. It would be hard to confuse that with a bad bearing. The ADG is more of a random sound. A bad bearing is a more consistent ticking that increases in frequency with rpm, and would not normally show up at idle unless it is really bad.

JoeHall · Nov 30, 2019

How many miles on the GW? Has the alternator ever been replaced before?

Yoda · Nov 30, 2019

Bike only has 39000 miles. Alternator has never been changed .

techdude2000 · Nov 30, 2019

Pull the alternator apart and physically check the rear bearing and the brushes.

Fred H. · Nov 30, 2019

I agree. Bad bearings in the alternator are much easier to fix than pulling the engine to replace the ADG, so it would make sense to check them out first.

LarryM · Nov 30, 2019

mine also happened at 2300 rpm. I also heard the noise at the rear of the alternator, but maybe my guess was just lucky. A bearing does sound a bit different than the ADG, but it's hard to describe.

cycledude · Nov 29, 2019

Your description sounds a lot like an alternator I removed from my bike a few months ago, other than the very worrisome noise it seemed to work fine. In my case The noise completely disappeared when I installed the new alternator.

Fred H. · Nov 29, 2019

The ADG is what couples the alternator to the engine, and they can also be a source of noise, especially at low rpms. You may be hearing ADG noise and not alternator noise at all.

GLblinded · Nov 29, 2019

Unfortunately Greg's right in that you can't accurately find a bad alt bearing with it installed in the bike. Removed and in your hand would be another thing.

GoldWingrGreg · Nov 29, 2019

On these engines, almost all bearing noise, good or bad, travels to the rear of the alternator. Using a stethoscope on a GL1800 for alternator bearing noise is usually very deceiving. Unfortunately a far better test is to install a known good alternator and see if the noise gets better.

IS this the Alternator bearings

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