1982 GS1100G - High frequency BUZZZ / Vibration

[kdchart]

Does anyone have any idea what could be the cause of a high frequency buzz / vibration that occures at around 60MPH and 4,000 rpm. It shakes the keys and they buz. When I hold the keys, the vibration is this there. You can even feel it on the gas tank. It sounds and feels just like when you BUZZZZ with your teeth.

The only thing I can think of is that it may have something to do with the valves???


I just got this bike, so don't really have a good feel for it yet. My 1980 GS850G definately does not vibrate like that.

[chef1366]

Does it do it with a full tank of gas? An empty tank will amplify your engine sounds like a guitar. Check and see if your gas tank rubber cushions are in place and still good. Two in the front and one or two in the rear.

[kdchart]

I've only put about 50 miles on the bike. The tank was 1/2-3/4 full. I put in a new starter and took the tank off. The rubbers were in pretty good shape.

Does this help any?

Kevin

[Arkaloid]

May be needing a carb sync as well

[fastpakr]

May be needing a carb sync as well

For a high speed vibration? :shock:

[kdchart]

What would loose engine mounts / bolts feel like?

[flyingace]

How does the bike idle? If that's OK, it seems unlikely to be a carb-synch problem. Are all cylinders firing? Check your plugs. How is the compression - are they within 20 PSI of each other? Is it possible the ignition or valve timing is off - that could make things shake.

Check for tightness of all engine mounting bolts too. That would be the best-case scenario.

[kdchart]

The bike idles fine. It also seems to have plenty of power. I'll try experimenting around with it more to see specifically when the vibration starts. It's really an annoyance to hear the keys start to buzz and feel the very high vrequency vibration.

Hopefully I can get more specifics.

Thanks - Kevin

[Guy]

Probably nothing. The 1000 seems to vibrate more than the 850. I put it down to the fact that it produces much more torque, has a much longer stroke. No harm to sync the carbs anyway.

[kdchart]

Still Vibrates after valve clearence

I guess the vibration could just be the nature of the beast, but thought I'd pursue it a little further.

I checked the valve clearance and almost all of them were >0.10mm. After getting everything in spec, the bike still vibrates about the same. I really thought I had the problem solved, but I guess not.

Anyone out there ride a 1982 1100G that is pretty much stock?

I just got the carb tune equipment, so that's next on the list. I'll also check the compression. The plugs all look OK to me.

[bwringer]

I'd also check all the engine mounting bolts and make sure they're all there and reasonably torqued. Also check all the points where the exhaust system is mounted and make sure it's not contactin the frame anywhere it shouldn't.

If all the hardware is present and accounted for, you can simply loosen all the mounts a bit and then retighten them, which sometimes is enough to change the resonant frequency of the vibration. Also make sure that the rubber mounts in your footpegs are still flexible.

These engines do not have counterbalancers, so there's a certain amount of vibration you just have to put up with. To reduce the high-frequency vibration on my GS850, I mounted weights on the ends of the handlebars, filled the handlebars with lead shot (not much difference, frankly), and I use heavy Sunline touring handgrips.

[kdchart]

Hey Brian - Been a while on my end. The vibration is really coming through the tank the most (which must be generated from the frame). I don't feel it on my hands much at all and the grips are stock.

I'll make sure to look at all of the engine bolts and exhaust parts.

I just got all of the carb balancing stuff, and still need to check the compression.

The bike runs pretty well all in all, it's just this vibration thing that is different than my 80 850G that has me a little nervous.

Thanks - Kevin

[scott hamm]

GS1100G - High frequency BUZZZ / Vibration

i'd also check the tires and rims.
you said it happens at approx 60 mph, thia sound like it could be a tire seperating or outta balance or maybe a wheels bearing.
how old is the bike and how many actual miles on it?

[kdchart]

The vibration actually happens at any road speed, and is a function of the RPM. The only time it really does not vibrate at all is at idle. Actual miles are around 15,000.

[koolaid_kid]

Not to discount your observations, but with the increase of displacement you also have an increase of moving mass. Thus, one would expect an increase in vibration, up to a point. My (totally stock) 83 1100E is not that much different from your G, and it does buzz. But it does not vibrate the keys.