Ever had the 40 amp alt fail?

[DeanR]

Can't remember hearing of a 40 amper fail.

Asking because I'm doing the upgrade. The donor alternator is at 96k miles, was installed in 2000 and run for 9 years. Has not been used for the last 5 years. Tests ok.

I can get it rebuilt locally with new brushes, bearings, regulator for $100. But since they seem to last forever, is working well, (although the alternator guy did say it sounded a bit noisy) and I don't really have the extra cash to throw at it at the moment....should rebuild it? or just install as is.



edit..I do know they have problems in the UK though.

 

[dwalby]

That's a good question Dean, how knowledgeable was the 'alternator guy' about the ST unit, and what does 'noisy' mean? If there's any detectable mechanical issues you might as well deal with them now rather than later. Not sure I'd throw a new regulator at it, but bearings and brushes might be worth it, and should bring the rebuild cost down.

 

[DeanR]

That's a good question Dean, how knowledgeable was the 'alternator guy' about the ST unit, and what does 'noisy' mean?

He was referring to possible bearing noise when he spun it up.

Right away he asked if it was from a GoldWing. Turns out a guy down the street knows him and would go to him without hesitation.

But I suspect this has another 100k in it as is! ..... I think

 

[raygks]

Dean, I had my '2000 40Amp went dead last month, bike has no added electrical farkles. It happened while riding on the highway @100kph, all of a sudden engine felt very "smooth" with all vibs gone,infact the power delivery became very subtle & nice to ride. I then noticed my voltmeter is reading only ~12+ volts instead of usual 14V+. Checked through the related connections per the service manual & there was no output from the alternator.

I use my bike for daily commute, had a spare battery so I had to swap them out every 2-3days(charge & swap) & ride without headlights on(daytime ride only). When I see the batt voltage dropped to ~11.5V(fuel pump + signal lights draw batt), I swap out the batt again until I can get my new alternator replaced by a shop.

It's not pretty uncommon for 40amp to fail where I'm located, probably because of the tropical rain, humidity & age. I had a buddy who had to replaced his 40amp as well 2years ago.

 

[ST1100Y]

It's not pretty uncommon for 40amp to fail where I'm located, probably because of the tropical rain, humidity & age.

Sensitivity for environmental influence seems to be the vulnerability of the air-cooled, thus not hermetically sealed 40A unit...

The brine from winter riding in UK causes the iron stator plates to rust, some just crack the covers, others actually seized the rotor (starter motor couldn't spin the engine...)

Friend had an unnoticed coolant leak for some time, in the aftermath the alternator in his '96 ABS-II/CBS died too, as the coolant was seeping over/through brushes, collectors and aft bearing... (so after first blowing a head gasket over stupid leaking elbow O-rings, another hefty bill struck shortly after...)

Treating the 40amper at least annually with some dedicated water repellent, penetrating, corrosion inhibiting solvent like ACF-50 seems to increase reliability significantly...


In retrospect the oil cooled, hermetically sealed 28A unit wasn't such a bad concept...

 

[dwalby]

He was referring to possible bearing noise when he spun it up.

Yeah, that's what I figured. Was he any more specific about whether or not he thought the bearings were marginal enough to warrant replacement? I have no clue if a little bearing noise is normal or not, so the 'possible' part sounds a little vague. But any time a bearing feels funny or makes noise its not worth guessing when it will eventually fail, especially if the part is already removed from the bike for easy replacement.

 

[schlep1967]

Two trains of thought come to me on this one.

First. The noise could just be because it hasn't been turned in 5 years and a little running might wear the dust/rust off of it.

Second. It hasn't been turned in 5 years. With the amount of work required to get it in, then find out you have an issue. Then have to take it out and put it in again. $100 dollars doesn't seem like too much for the peace of mind.

 

[Jim Van]

Can't remember hearing of a 40 amper fail.

Asking because I'm doing the upgrade. The donor alternator is at 96k miles, was installed in 2000 and run for 9 years. Has not been used for the last 5 years. Tests ok.

I can get it rebuilt locally with new brushes, bearings, regulator for $100. But since they seem to last forever, is working well, (although the alternator guy did say it sounded a bit noisy) and I don't really have the extra cash to throw at it at the moment....should rebuild it? or just install as is.



edit..I do know they have problems in the UK though.

I would remove, clean & check the brush length. Compare them to new brushes at the rebuilder. Easy to do, just remove the thin metal cover and you will see the brush holder secured by two screws. When I checked mine at 54K miles, they were only worn about 1/16" . The condition of the slip rings is probably more important than the brush wear. Slip rings should be smooth without grooving.

How noisy are your bearings compared to a rebuilt alternator at the rebuilders ?? Pick up a few small alternators at the rebuilder and spin them. Yours may sound about the same .........

 

[Woonjas]

I had the 40A alternator's voltage regulator die on me, was easy enough to replace without removing the alt. Just order the correct Denso part at auto parts store instead of from Honda, a lot cheaper. ;-)