Vibration when accelerating


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ripsaw
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Vibration when accelerating

Post by ripsaw » Wed Feb 22, 2012 7:24 am



I've just bought a 1986 Apencade. I've found when accelerating there's an annoying vibration as though an engine mounting bush is missing. It eventually goes by either easing off the throttle and gently easing it back on, or increasing the throttle gently whilst it vibrates and it passes. This can't be right, does anyone have any idea of what it could be? :?:



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virgilmobile
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Re: Vibration when accelerating

Post by virgilmobile » Wed Feb 22, 2012 7:37 am

I guess that the motor mounting bolts could be loose,or even something related to the driveshaft,however mine growls at me around 1000-1200 rpm.I just need to sync the carbs again.

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D2D
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Re: Vibration when accelerating

Post by D2D » Wed Feb 22, 2012 7:41 am

More info .. front of the bike or rear. Could be a number of things .. loose or broken or even missing engine mounts, bad wheel bearings, bad swing arm bushings and bearings, unbalanced tires, bad final drive etc. At what speeds does it start and go away ? What if anything have you checked to narrow it down?

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Re: Vibration when accelerating

Post by mervk » Wed Feb 22, 2012 7:42 am

If the vibration is constant at a certain speed range, that is, at a certain speed it starts, then keep accelerating and it always goes at a set higher speed, then I would suspect you've thrown a wheel weight, and need the wheels balanced.

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poffutt
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Re: Vibration when accelerating

Post by poffutt » Wed Feb 22, 2012 1:36 pm

I am a newby to Goldwings and shaft drive. But with my Ford Bronco I am an expert. twice I have had to change u-joints in the drive shaft. The symptoms are exacaly as you describ. When giving it gas you get a viberation. When you let off the vibration goes away. if my Gold wing was acting like this, the first thing I would check would be the drive shaft u-joints.

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WingAdmin
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Re: Vibration when accelerating

Post by WingAdmin » Wed Feb 22, 2012 4:04 pm

It sounds like vibration from the primary chain, the massive chain that connects the engine to the transmission. If the carburetors are out of sync, the uneven power pulses from the cylinders set up a resonant vibration in the chain at lower RPM, particularly under high load (think lugging the engine going up a hill in too high a gear). The end result is a lot of vibration, sometimes sounding like a box of nuts and bolts rattling around inside there.

The solution is to do a carb sync.

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Re: Vibration when accelerating

Post by detdrbuzzard » Thu Feb 23, 2012 6:58 am

if it the engine you might need a carb sync
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ripsaw
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Re: Vibration when accelerating

Post by ripsaw » Thu Feb 23, 2012 8:36 am

Thanks for all the info, I'll give a little more myself. My bike was in the garage for about 2 months end November 2011 to end of Jan 2012. The bike was in for a MOT, carb balance and I had another problem of both tyres going flat within a week. The vibration was there before the bike went in and seems a little bit better now. I'm assuming the wheels were removed (the back one in any event as I needed a brake disc for the MOT) to have cleaned them up and sorted them out.

The vibration seems to start when I'm just cruising along at any constant speed and then apply the throttle. But on saying any constant speed, I'm meaning mainly lower speeds around town and bypasses (30 - 40 mph) Once it passes the vibration it's fine until I want to accelerate again. Other than that it seems to run reasonably well for the age of it.

ripsaw
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Re: Vibration when accelerating

Post by ripsaw » Mon Feb 27, 2012 7:41 am

D2D wrote:More info .. front of the bike or rear. Could be a number of things .. loose or broken or even missing engine mounts, bad wheel bearings, bad swing arm bushings and bearings, unbalanced tires, bad final drive etc. At what speeds does it start and go away ? What if anything have you checked to narrow it down?
More of a problem at lower speeds, the vibration feels like it's coming through the seat.

ripsaw
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Re: Vibration when accelerating

Post by ripsaw » Mon Feb 27, 2012 7:52 am

WingAdmin wrote:It sounds like vibration from the primary chain, the massive chain that connects the engine to the transmission. If the carburetors are out of sync, the uneven power pulses from the cylinders set up a resonant vibration in the chain at lower RPM, particularly under high load (think lugging the engine going up a hill in too high a gear). The end result is a lot of vibration, sometimes sounding like a box of nuts and bolts rattling around inside there.

The solution is to do a carb sync.
The vibration feels like it's coming through the seat, and it does sound like a box of nuts and bolts rattling around, but the carbs have been balanced (well at least I paid for them to be balanced)

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Re: Vibration when accelerating

Post by WingAdmin » Mon Feb 27, 2012 9:43 am

It really sounds like the carb balance/chain problem. My 1100 will still do it when the carbs are perfectly balanced, but only at very low RPM and high throttle settings. The better quality (more accurate) carb sync, the less likely the noise is to happen. You might want to have a look at getting the carbs synced again. They're very touchy and really have to be done well.

ripsaw
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Re: Vibration when accelerating

Post by ripsaw » Tue Feb 28, 2012 11:27 am

WingAdmin wrote:It really sounds like the carb balance/chain problem. My 1100 will still do it when the carbs are perfectly balanced, but only at very low RPM and high throttle settings. The better quality (more accurate) carb sync, the less likely the noise is to happen. You might want to have a look at getting the carbs synced again. They're very touchy and really have to be done well.
What's involved with a carb sync? Can it be done DIY? I also find my wing is a little thirsty.

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Re: Vibration when accelerating

Post by WingAdmin » Tue Feb 28, 2012 12:55 pm

ripsaw wrote:What's involved with a carb sync? Can it be done DIY? I also find my wing is a little thirsty.
Have a look at: How to synchronize your carburetors

jwhpostal
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Re: Vibration when accelerating

Post by jwhpostal » Mon Aug 18, 2014 10:04 am

I'm having the exact issue with my 85 LTD. Did you ever figure out what caused it. I've synced the carbs and it didn't help bit. I've isolated the vibe to the engine because by dragging the clutch while stopped I can get it to "growl". I'm thinking it has to be a worn bearing somewhere like maybe the clutch basket is deflecting under torque and rubbing the housing.

Nik27
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Re: Vibration when accelerating

Post by Nik27 » Sun Mar 19, 2017 1:57 pm

I experience a very similar vibration from 1400 rpm to 2300 rpm.
Doing a synchronization on the carbs has done very little to help this...their is quite a rattling sound at idle from around the stator/alternator shaft area of my engine and a slight misfire through the carbs. Other than that it pulls like a train and plugs are a good colour.
I had recently changed the alternator shaft damper system in an effort to reduce/end the vibration but this hasn't achieved anything.
Any help much appreciated :D

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CrystalPistol
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Re: Vibration when accelerating

Post by CrystalPistol » Sun Mar 19, 2017 2:34 pm

What RPM range in what gear at what speed under how much throttle? It's hard to tell from your posts.

GL1200s are 4 cylinder bikes with 4 carbs with a designed rev range idle to 7,500 rpms. GL1500s are 6 cylinder bikes with two carbs with a design rev range of idle to 5,500 rpms. You can puttyputt around on a 1500 in a higher gear at lower speed and remain smooth because power is devided up into 6 pulses every two engine revs. A 1200 devides it's power into 4 pulses every two revolutions and it's tuned to make it's power at a higher range. A 1500 has rubber engine mountings, a 1200 has it's engine bolted solidly in place.

If you ride a 1200 at low speed in a higher gear at a low engine rpm and then open throttle, it will vibrate. Keep those rpms up 2500 or 3000 before opening throttle, they are happiest.
Image

Nik27
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Re: Vibration when accelerating

Post by Nik27 » Sun Mar 19, 2017 5:18 pm

Hi there....the vibes come in at 1800 and stop above 2400 rpm. At idle you can hear a rattling from the alternator side.
I had replaced the alt. drive shaft with a newer one as I had read the damper balls cause this vibration, turns out setting the backlash also has an effect on the vibration too!!
If the balls don't move/rattle in the unit I guess they don't dampen and would therefore cause a nasty vibration??

tire joe
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Re: Vibration when accelerating

Post by tire joe » Mon Mar 20, 2017 8:00 pm

Nik27 wrote:Hi there....the vibes come in at 1800 and stop above 2400 rpm. At idle you can hear a rattling from the alternator side.
I had replaced the alt. drive shaft with a newer one as I had read the damper balls cause this vibration, turns out setting the backlash also has an effect on the vibration too!!
If the balls don't move/rattle in the unit I guess they don't dampen and would therefore cause a nasty vibration??
Honda is a high speed engine keep the rpms above 3,500 it will run smooth with power.



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