gl1200 aspy vibration at 4000-5000rpm


Information and questions on GL1200 Goldwings (1984-1987)
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maciejl73
Posts: 2
Joined: Fri Aug 15, 2014 3:01 pm
Location: Poland
Motorcycle: 1980
gl 1100

gl1200 aspy vibration at 4000-5000rpm

Post by maciejl73 » Sat Mar 02, 2019 1:56 am



Hi everyone members. Carbs cleaned and synced, spark plugs changed, at low rpm ride great but at about 4krpm beginning vibration more and more sounded til 5krpm and then ride like new without vibration and noises. I`ll be grateful for any help.



Ernestee00
Posts: 2
Joined: Thu Jan 17, 2019 3:06 pm
Location: Netherlands
Motorcycle: gl1200 aspencade 1986

Re: gl1200 aspy vibration at 4000-5000rpm

Post by Ernestee00 » Sat Mar 02, 2019 6:06 am

Hi Macie jl 73,

I have gone through the same with my 86 Aspy.
I notice that after repairing the alternator drive (yes , with all it's springs, balls and clutch) vibration will set in between 4k and 5k.
This drive also causes the 2000 rpm rattle when the friction material is no longer able to provide friction.
Main causes for that:
-Balls stuck in the housing
-Friction material deteriorated or worn

The 4-5 k vibration has more to do with the engine not pulling evenly or the rear drive ( from dampener to wheel) not providing enough cushioning.
After replacing all the parts in the final drive line, by either new or well preserved used ones, this was eliminated.

One can easily feel the result from this stiff rear drive when pulling WOT in fifth from 2k to redline and feel the alternator drive start working, after 4-5 k the clutch mechanism of the alternator drive is riding on the springs rather than the clutch, at that time the steel balls inside "try"to balance the alternator drive and the vibrations from the engine.
If the mechanism is working correctly, when decelerating with closed throttle, below 2.5 k the alternator clutch closes and the noise and vibration disappear.

In your case, a lot of these parts can be worn or broken and I would ignore the effects, once you start working on this, it will eat budget and time.

One thing you could do, especially when the bike has not been worked a lot and has been in storage for a long time, is use flushing oil (ATF, some amount of diesel) and hope this will dissolve the crud in the track for the balls. No guarantee though, as these additions, I suspect. also could wreck the very thin clutch material layer in the alternator clutch, when used for too long.

maciejl73
Posts: 2
Joined: Fri Aug 15, 2014 3:01 pm
Location: Poland
Motorcycle: 1980
gl 1100

Re: gl1200 aspy vibration at 4000-5000rpm

Post by maciejl73 » Sat Mar 02, 2019 6:29 am

It`s very interesting, what You write. And it`s very possible that You are correct diagnosis. Next winter the engine will move out from the frame, so I`ll check it. Thank you a lot.
Meanwhile I`ll flash the engine and hope, it`ll cure.
What other members think? Is it good diagnose?

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