Baffling problem with OEM alternator drive unit


Information and questions on GL1200 Goldwings (1984-1987)
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Redwing52
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Location: Milwaukee, Wisconsin
Motorcycle: 1999 GL1500 SE

Baffling problem with OEM alternator drive unit

Post by Redwing52 »



Hello everyone.
On one of the other sites there have been quite a few issues with the GL1200 and a buzzing, vibrating at about 2,000 RPM. No one has come up with any real answers. It seems the problem is associated with the alternator drive unit. Has anyone gone through this issue and have any real knowledge of what the problem might be. It seems that everyone is stumped. If you take the drive unit out and shake it there are a total of 4 units involved. It is evenly split. Two of the units the internal ball bearings rattle like marbles while the other two make no noise. I would think the two that rattle are no good. Problem is at least one person took out one, that buzzed and vibrated. It had no rattle when you shook it. He replaced it with one that rattled and he said that fixed the vibration? The poster on this thread took his out and it rattled. He bought a used one from eBay and it does not rattle. Can anyone help please. Here is a link to the thread. I'll be checking back so thanks in advance for any help on this real puzzler.
http://www.goldwingfacts.com/forums/2-g ... -unit.html



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roadwanderer2
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Motorcycle: previously owned 83 GL1100A aspencade traded for a motorhome, 1981 honda GL500i silverwing interstate, 1974 yamaha xs400, 1974 Honda cb450 twin cam, 1983 honda vt30, 1982 honda 700 shadow, 1972 cb750four, and my first bike, a brand new 1982 honda CM400e. now own-1986 GL1200 aspencade SEi
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Re: Baffling problem with OEM alternator drive unit

Post by roadwanderer2 »

i too have an alternator that has a rattle inside it, but it never gave me any problems while the bike was running at any rpm. i had to replace it due to complications with the alternator shaft and flywheel and the replacement also has the rattle in it. only thing i got with the old one was while going up thru the gears it sounded like a turbo unit which i think is pretty cool. oh, btw, my 1100 has the same sound when going up thru the gears, but i know its working because at above 2,000 rpm, my volt meter is at 14.5 volts. i wouldn't be concerned with it unless the volts drop down to 9 volts.

stuart.

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CrystalPistol
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Re: Baffling problem with OEM alternator drive unit

Post by CrystalPistol »

The only part that moves inside the alternator is a round rotor with a permanent magnet in it. It's on a shaft and just "spins".

If you mean it vibrates (shudders) at 2,000 rpm in gear on a pull .... drop a gear and the vibes will smooth out. GL1200's have 4 cylinders of 300cc each which each provide one power pulse every two engine revolutions (so a pulse every 180 degrees of crank rotation) and the engine is tuned for a higher power band (7,500 RPM redline) than 1500s (5,500 RPM redline) , and the engine is mounted solid. A GL1200 at 2,000 rpm pulling will vibrate.

Gl1500s have rubber mounted engines and six 250 cc cylinders that each fire every two revolutions (so a pulse every 120 degrees of crank rotation) and the GL1500 is tuned to run smoother at lower RPMs with the cost being less top end RPM range.

I've never heard of this alternator drive vibration issue until I read of "it" on "
another site" myself and I've only had my GL1200 since 1995, but any experienced 4 cylinder Gold Wing rider knows to keep the revs up when pulling ..... they like 3,000 really well. :D
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roadwanderer2
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Joined: Thu Aug 08, 2013 4:03 am
Location: Tucson Arizona
Motorcycle: previously owned 83 GL1100A aspencade traded for a motorhome, 1981 honda GL500i silverwing interstate, 1974 yamaha xs400, 1974 Honda cb450 twin cam, 1983 honda vt30, 1982 honda 700 shadow, 1972 cb750four, and my first bike, a brand new 1982 honda CM400e. now own-1986 GL1200 aspencade SEi
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Re: Baffling problem with OEM alternator drive unit

Post by roadwanderer2 »

CrystalPistol wrote:The only part that moves inside the alternator is a round rotor with a permanent magnet in it. It's on a shaft and just "spins".

If you mean it vibrates (shudders) at 2,000 rpm in gear on a pull .... drop a gear and the vibes will smooth out. GL1200's have 4 cylinders of 300cc each which each provide one power pulse every two engine revolutions (so a pulse every 180 degrees of crank rotation) and the engine is tuned for a higher power band (7,500 RPM redline) than 1500s (5,500 RPM redline) , and the engine is mounted solid. A GL1200 at 2,000 rpm pulling will vibrate.

Gl1500s have rubber mounted engines and six 250 cc cylinders that each fire every two revolutions (so a pulse every 120 degrees of crank rotation) and the GL1500 is tuned to run smoother at lower RPMs with the cost being less top end RPM range.

I've never heard of this alternator drive vibration issue until I read of "it" on "
another site" myself and I've only had my GL1200 since 1995, but any experienced 4 cylinder Gold Wing rider knows to keep the revs up when pulling ..... they like 3,000 really well. :D
i have to agree with you about these 1200's dealing with the higher rpm's crystal. i noticed the difference between my 1100 and my 1200 in the upper 2,000's range when im in 5th gear. where as i have to go down 2 gears with my 1100 for pulling power when in 5th gear, my 1200 only requires going down 1 gear to do the same pulling.

stuart.

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geraldm
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Re: Baffling problem with OEM alternator drive unit

Post by geraldm »

I've never heard of this alternator drive vibration issue until I read of "it" on "
another site" myself and I've only had my GL1200 since 1995, but any experienced 4 cylinder Gold Wing rider knows to keep the revs up when pulling ..... they like 3,000 really well. :D[/quote] OR MORE :D . Yes when first owning my 86a i lugged it terribly for an hour or so
before learning to keep the revs up . at first the higher revving engine sounds bothered me after running lower rpm machines for years but soon learned to appreciate the higher power band . probably the worst thing you can do to these engines is to lug them .

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roadwanderer2
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Location: Tucson Arizona
Motorcycle: previously owned 83 GL1100A aspencade traded for a motorhome, 1981 honda GL500i silverwing interstate, 1974 yamaha xs400, 1974 Honda cb450 twin cam, 1983 honda vt30, 1982 honda 700 shadow, 1972 cb750four, and my first bike, a brand new 1982 honda CM400e. now own-1986 GL1200 aspencade SEi
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Re: Baffling problem with OEM alternator drive unit

Post by roadwanderer2 »

don't feel bad, i was the same way when i first started riding my 1100. i learned the hard way. i was in traffic going about 40 mph in 5th gear when i had to slow way down to about 25, well i kept it in 5th and tried to give it throttle to speed up and when i tried to, the bike would hardly move. thats when i started shifting down to eventually 2nd gear to pick up power, and ever since then i always shift down a gear or 2 to keep the revs up so i have power when i need it. even at interstate speeds i always shift down 1 gear to pass big rigs or go around slower vehicles.

stuart.



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