Bad vibrations

[Sidcar]

Going out for a Sunday morning run last month I noticed the voltage on my GL1500 outfit was down to 9.5 volts and falling. Instead of a nice ride out it was a case of alternator out. The fault was traced to the windings in the armature.
I wanted to fit a high output replacement but no one in the UK seemed to stock Compufire alternators. I emailed Compufire for the name of their UK agent, if they had one, but never received a reply and to buy one straight from the US would cost a fortune.
In the end I fitted a WPS, 90 amp, made in Taiwan (but I gather genuine Honda units are now made in China).
The unit charges fine but knocks and vibrates when cold, improving to harshness and vibration when at operating temp. I fitted new coupling pads (and refitted the old ones to see if that made a difference) and then refitted the old alternator, smooth as silk but no charge.
The chap I bought the alternator off couldn't be more helpful sending me another unit to try but it was just the same. The only thing that improved the problem was to fit a one mm washer one each bolt between the alternator and the engine.
Any ideas would be welcome.

Sid

[Sidcar]

I don't know if this video clip helps but this is when the engine is cold, hence it's reluctance to idle.
The noise and vibes are worse at idle and seem to disappear above 2000rpm.
Using a sound stick the noise seems to be coming from the back bearing on the alternator.





Sid

[WingAdmin]

I know there have been issues with aftermarket alternators in the four "paddles" being of the incorrect dimensions that have caused this sort of problem. Do you have a micrometer where you could measure the dimensions and compare them to the dimensions of the stock alternator?

[Sidcar]

Vane
thickness. Old. 4.1mm New 3.8mm
Height. Old. 18.5. New 18.4
Depth. Old. 18.7 - 19.4. New. 19.3 - 19.4
Protrusion, measured from face of alternator where it meets the engine to the end of the hub
Old. 60 mm. New. 57.5 mm

Odd that the new unit does not protrude as far as the old one but spacing it out 1mm (1mm washer on each bolt between alternator and engine) seems to reduce the noise.

Sid

[WingAdmin]

Vane
thickness. Old. 4.1mm New 3.8mm
Height. Old. 18.5. New 18.4
Depth. Old. 18.7 - 19.4. New. 19.3 - 19.4
Protrusion, measured from face of alternator where it meets the engine to the end of the hub
Old. 60 mm. New. 57.5 mm

Odd that the new unit does not protrude as far as the old one but spacing it out 1mm (1mm washer on each bolt between alternator and engine) seems to reduce the noise.

Sid

If I remember correctly, it was the vane width that caused the problems when I read about it before. The owner tried using epoxy or some other material to build it up to spec, but it didn't last.

[Sidcar]

I wonder where the resin went when it fell off. Don't think I'll try it.

Sid

[RoadRogue]

you could try swappin the vanes from the old Alternator onto the new one, you dont have anything to lose in the attempt

[Bluewaterhooker0]

I installed a Lactrical 85A alternator on my 1500 in January of 2015. I also experienced odd noises and vibrations from the first one they sent. I also tried 'pulling' the alternator out from the seated position using washers, and it did quiet the alternator to a certain extent. In the end, I had a new unit sent, and it was noticeably quieter (whining noise), and with less vibration. New insulators were installed from the beginning. The noise also seemed to emanate from the rear bearing when using a stethoscope. The whining noise has either gotten much better, or I've just become accustomed to it over the last year. I am of the opinion that these noises, and possibly the vibrations, are characteristic of these higher amperage alternators. Possibly due to the doubling of the work effort that the additional output puts on essentially the same size casing. Anyway, a year and 5K miles later, it's still working fine. Great voltage readings at all RPMs, and no dimming of the lights under any circumstances. Where did you find a high output WPS alternator ? I searched and found their catalog for 2010, listing only a 40A replacement. Also, how did you determine it is of Taiwan origin ? I would place more confidence in Taiwanese products over Chinese, and would like to see what they have.

[Sidcar]

Annoyingly the vane hub on the new alternator is press fit so can't be swapped.
The WPS part number is:
On the box. 12485N-90A
On the unit. 1245N-90A
It's got "Made in Taiwan" on the box.

Sid

[WingAdmin]

you could try swappin the vanes from the old Alternator onto the new one, you dont have anything to lose in the attempt

I think that would be my approach.

[Sidcar]

I've now tried a third alternator, courtesy of Dave at AwingAway Goldwing specialists, and though the vibes are a bit better, it's still not as smooth as the old 40 amp unit.
Looks like I'll have to just live with it for the time being but I'm now looking out for a 40amp unit, at the right price, to see if that cures the vibes.

Sid

[Sidcar]

I saw a used 40 amp alternator on eBay and made the bloke an offer which ,I'm pleased to say, he accepted.
The unit is now on the bike, it charges well and there are no knocks or vibrations, hot or cold. The engine is back to its old smooth self.
Unfortunately I can't try it on the road, I've just had surgery to my back so I can't ride for the next six weeks (or lift, or bend, or drive, gonna be a long, tedious six weeks).

Sid

[RoadRogue]

well at least you solved the problem, hope you heal well and quickly.