1500 alternator

[toanogreen]

Question #1
Is it possible for an alternator with 56K on the bike to go bad?
Mine did and I replaced it. The one I replace it with was not new, but had limited miles on it.
Now it has a "humming" noise in it. It's not noticeable at idle, but it is when I rev the engine a little and get on my way.
Question #2
What could be the cause?
Question #3
What's the fix?

Thanks in advance

[robb]

What kind of shape was the rubber dampener in, look worn or in pieces instead of one four part assembly. If worn, replace.

Pop off side cover and use and air supply to blow out alternator. It it has been driven in heavy rain and left a few weeks the internal works can rust, but it will wear off with use.

[toanogreen]

I do remember the rubber dampner came out in pieces. I thought that was the the way it was supposed to be.
I will go back and recheck/replace. It also may have been on a shelf sitting for awhile as well.

Thanks

[Larrs2]

I am real sure your bearing is bad on the alt. The back bearing is the most problematic and will take out the back housing if left bad to long. You should hear a rumble around 2000 rpm if I am not mistaken. It would be advisable to change the front bearing and brushes at the same time. The brushes need to be soldered in. Larrs 2

[toanogreen]

Thanks for the info. How m uch trouble/time needed to replace?
Or I may just replace the alternator.

[Larrs2]

Maybe 3 hours with the proper tools. The parts can be got from your local auto supply. I encountered problem with removing the back bearing. I ended up using a very thin battery cable puller. Good luck. Larrs

[capnfred]

Larrs, My front bearing has gone south, had no problem pressing the old bearing out, the bearing is retained by the the cover on the front, held on with three machine screws, the rear bearing was easy, providing you have the right tools, experience, and patience...do you have the part numbers for the bearings you purchased at an autoparts store... the rear bearing appears to be readily available, the front bearing and seal numbers do not cross to anything using the internet.... thanks in advance...

Capn

[wiredgeorge]

Most all bigger towns will have stores that specialize in bearing sales. The bearings used on a motorcycle are not special purpose items but are just standard bearings. Many OEMs will actually tell you what type bearing is used (at least Kawasaki does) PLUS the OEM part number. Noted that the bearings on a GL1500 alternator are NOT labeled other than the OEM part number which doesn't help ID the bearing.

This link is a pretty good tutorial on how bearings are characterized so if you have a metric caliper you can go into a store selling bearings (or order the correct one through an auto parts place) using the info here:

http://www.gizmology.net/bearings.htm