Different vibrations after fueling

[faffi]

Near the end of my previous ride, and after filling the tank, my V9 got a new kind of vibrations that were primarily noticeable around 3000 rpm (60 mph indicated). Very fine buzzes, the kind you usually noticed with inline fours. You know, the really annoying buzz. I can feel them in the handlebars, seat and see it on the speedo needle that buzz into a fine blur. It gets worse with load.

It was the same today, and did not change after I filled the tank with petrol on a different station. Both stations are reputable brands with plenty of traffic going through, so fuel should be fresh.

I cannot hear anything ringing or any other noises that have not been there before, and engine power seems identical to before.

I understand this is not much to go by, and it could of course be a coincident that it happened after filling the fuel tank with new petrol/gas. But has anybody else experience similar vibrations appearing suddenly - AND found the culprit?

[lazlokovacs]

I am by no means saying that this is the case for your engine but I had a similar sensation on a Calvin many years ago. People thought I was nuts but I was certain a new vibration had just appeared out of nowhere.

A year later the crank locked up as the oil pump sprocket had worked its way loose enough to stop circulating oil 

[faffi]

Ouch I am going to check the bike over externally first, checking for any fastener or part that may have come lose. An oil pump sprocket coming off, though - what are the chances Thanks for sharing the information!

[SIR REAL ED]

Erik,

Maybe your bike has been listening to this video?

https://www.youtube.com/watch?v=nGy9uomagO4

[Tkelly]

Maybe you should drop down a gear ,60 mph at 3000 rpm doesn’t seem right.

[chuck peterson]

Drop two gears and call me in the morning…

4-6k w a steady throttle reaps rewards only found on a Guzzi

There’s a sweet spot at 4250…

And 4850

And 5250

5750

Even, gasp! 6000…

Let that motor sing.

But i always say that. Yes, things buzz at 3k that smooth out above that. At 21k mine still seems to be getting smoother.

In car parlance, turn the radio up…

Loose nuts bolts fixtures can be found w the motor off and tapping w a rubber mallet, maybe you’ve got something loose there. Pound on the tires with a massive whack to see if something buzzes elsewhere on the bike

[faffi]

Erik,

Maybe your bike has been listening to this video?

https://www.youtube.com/watch?v=nGy9uomagO4

That could be 

[faffi]

Maybe you should drop down a gear ,60 mph at 3000 rpm doesn’t seem right.

Indicated, so actual 57? IIRC the engine theoretically turn 3480 @ 62 mph, giving 3100 @ 57. In fifth, the period is around 50 mph actual, giving the same rpm. So the buzz happens around 3100 rpm, give or take a little, and increase with load. There is no buzz below or above the narrow range. The buzz is new, trembling vibrations have always been there, also increasing with load.

Dropping to 4th at 50-70 mph is not smooth, either, and generally less comfortable than using taller gears due to higher frequency shakes, but I do drop down for hills or strong headwinds.

[Moparnut72]

Wind 'er up. I haven't ridden an 850 but my V7 is almost never ridden at that rpm unless in town in lower gears. My V7 basically lives at 4,000+. Small blocks love to rev, big Blocks too.
kk

[SIR REAL ED]

That could be 

Your bike may be confused about it's gender and might self-identify as an in-line four.

Removing pistons is simple surgery, adding pistons, not so easy.....

Is the buzz there at the same rpm's in all gears, or only at that rpm at some speeds?

Same rpm at all speeds would indicate something is a bit loose or worn.

Road speed variations could be a lot of things.  Key fob, helmet visor, new eye glasses.......

Try changing tire pressure to see if it changes the noise.

[Dirk_S]

Wind 'er up. I haven't ridden an 850 but my V7 is almost never ridden at that rpm unless in town in lower gears. My V7 basically lives at 4,000+. Small blocks love to rev, big Blocks too.
kk

Keep in mind that the hemi head small blocks appear to run optimally at lower RPM than the older Herons. And the V9 maxes at 6800 RPM, the V7 III at 7200 RPM.

(this may not have any worth with faffi’s issue; just pointing out that Heron heads and hemi head small blocks are not be so apples-to-apples)

[normzone]

"Loose nuts bolts fixtures can be found w the motor off and tapping w a rubber mallet, maybe you’ve got something loose there. Pound on the tires with a massive whack to see if something buzzes elsewhere on the bike "

With my Bassa, I have found loose crash bars, motor mount bolts, shifter linkage, and more delivering what sounded like an RPM related pings. 

[faffi]

Keep in mind that the hemi head small blocks appear to run optimally at lower RPM than the older Herons. And the V9 maxes at 6800 RPM, the V7 III at 7200 RPM.

(this may not have any worth with faffi’s issue; just pointing out that Heron heads and hemi head small blocks are not be so apples-to-apples)

  Max torque at 3000 rpm according to Guzzi, so that is not lugging.

[faffi]

Y

Is the buzz there at the same rpm's in all gears, or only at that rpm at some speeds?

Same rpm at all speeds would indicate something is a bit loose or worn.

RPM is the common nominator, and more load at that RPM increase the buzz. Worn would be strange, especially since it happened between me stopping for gas and starting up again a minute later. But something loose it can be. My first suspect was the fuel, but it did not change when I filled up next time at a different gas station.

[faffi]

"Loose nuts bolts fixtures can be found w the motor off and tapping w a rubber mallet, maybe you’ve got something loose there. Pound on the tires with a massive whack to see if something buzzes elsewhere on the bike "

With my Bassa, I have found loose crash bars, motor mount bolts, shifter linkage, and more delivering what sounded like an RPM related pings.

Good tips. As I think I've mentioned already, I will look/knock in search of something loose.

[Bulldog9]

Max torque at 3000 rpm according to Guzzi, so that is not lugging.

3K is not technically lugging it, but every one of my seven Moto Guzzi's much prefer to be over 3,500 to 4,000 RPM.

Take it out and bang it off the rev limiter (okay okay, just below) for half a day. Your bike might just be tired of being ridden by an old lady. (LOL.... I kid I kid, but I am making a point)

[faffi]

3K is not technically lugging it, but every one of my seven Moto Guzzi's much prefer to be over 3,500 to 4,000 RPM.

Take it out and bang it off the rev limiter (okay okay, just below) for half a day. Your bike might just be tired of being ridden by an old lady. (LOL.... I kid I kid, but I am making a point)

I often rev it to or close to the limiter, but I see no reason to criuse at high rpm. More vibrations, more noise, more fuel.

[SIR REAL ED]

When you stop to refuel, are you chugging an energy drink?

Lots of kinds of buzz (American slang!) out there!   

Does it seem to be related to the amount of gas in the tank?

Worn gas tank mounting rubbers perhaps?

[faffi]

Does it seem to be related to the amount of gas in the tank?

Worn gas tank mounting rubbers perhaps?

No and no, but it would have been a simple fix.

[Bulldog9]

I often rev it to or close to the limiter, but I see no reason to criuse at high rpm. More vibrations, more noise, more fuel.

When I took my Stornello on my 3k mile trip to Arkansas and back, I stayed in the 4-6K rev range and averaged over 45 mpg. Run your motor at higher rpm. Keep it above 4k. It will be happier.

You're gonna get weird vibes cruising at 3k or less. Or keep ignoring everyone's advice.

[PJPR01]

Near the end of my previous ride, and after filling the tank, my V9 got a new kind of vibrations that were primarily noticeable around 3000 rpm (60 mph indicated). Very fine buzzes, the kind you usually noticed with inline fours. You know, the really annoying buzz. I can feel them in the handlebars, seat and see it on the speedo needle that buzz into a fine blur. It gets worse with load.

It was the same today, and did not change after I filled the tank with petrol on a different station. Both stations are reputable brands with plenty of traffic going through, so fuel should be fresh.

I cannot hear anything ringing or any other noises that have not been there before, and engine power seems identical to before.

I understand this is not much to go by, and it could of course be a coincident that it happened after filling the fuel tank with new petrol/gas. But has anybody else experience similar vibrations appearing suddenly - AND found the culprit?

I still think it could be fuel related...you could add a fuel additive to the tank to get ride of any water that may be in the bad gas, and ensure that it eliminates that completely, or drain the tank as best as possible.  I've had a bad case of gas a couple of times that caused the bike to run very poorly, not just minor vibrations as you are mentioning.  Other than that, some screws have come loose, but it's too much of a coincidence that it happened immediately upon filling up.