"micro-vibrations" on my F800GT

martco

sorry but that's the best terminology I can put to it

13 reg bike with couple careful owners (incl me last 4 years) coming up on 50k kms serviced back in June when it also got a nice set of metzelers more because of age then wear, I've never been in any kind of incident

been riding regularly but circumstances I didn't really get away for any spins this year so far, all local stuff

SO first proper trip in a good while on quality road surfaces down the M11 etc. into Wexford this weekend

after about 30 mins my hands are going dead/numb and I can feel/hear just something just off possibly like a tanging sensation in my teeth dunno (I know it sounds weird but best way I can describe)

I had a look around bike seems ok

Wondering what could it be? Balancing (though I thought that would be more obvious/not as barely there as this feels) Shockers or other damping? head or wheel bearings?

jeremyr62

It definitely didn't do it before? Most bikes vibrate a bit. You haven't changed anything or done significant maintenance?

You could try tightening the engine mounting bolts. Worked for me once.

martco

https://www.boards.ie/discussion/comment/119637281#Comment_119637281

no definitely never this

only thing I can think of immediately is the tyres but they were bought and fitted at maddocks and seem fine generally, this is very fine/high frequency feel off it not typical wobblyness that would come/go at a certain speed...

I've been on plenty of longer excursions on the bike (just that was first one I had a chance at this year)

bladespin

Does it have adjustable suspension? Could anyone have been 'fixing' the settings?

Edit* worth checking tyre pressures too.

goblin59

wouldn't be the throttle bodies a tiny bit out of sync?

Closest i've heard is wheels being slightly off balance as well.

jeremyr62

Could be the tyres I suppose if that's all that has been changed. The tread pattern might be setting up some weird resonant frequency through the bars. I would try radically altering the tyre pressures and see if that makes a difference.

You haven't changed? Become more sensitised to high frequencies, whatever that means :-)

galwaytt

the most obvious thing if it's the only thing that's changed, is the tyres. Are they balanced properly ?

martco

I will play with the tyre pressures and see this weekend…

if no improvement then I’ll go back to maddocks and query the balancing

Lorddrakul

It is worth looking at stuff like bar ends, battery, and other large components that might be a little loose. As a bike wears and builds the miles, it's not unheard of for things to move about a bit and create this kind of resonance.

Have you checked the condition of the drive belt? That kind of vibration can sometimes come from the final drive too.

But as has been pointed out, start with the tyres.

martco

ok

so I upped the pressure to 3.0bar front and rear, went for a spin and it felt if anything amplified

feels like the front end, reckon has to be either the steering/headset or front wheel bearings :(

going to get the balancing verified just to be sure

if it is a bearing I'm surprised tbh given the genuine mileage but have read on couple of the forums about shot F800 headset's with as little as 20k miles done so there u go?! but I suppose accept too that the bike is heading for 10 years young now...

on a positive thought I'm a reasonable amateur mechanic....now wondering if this might be a nice winter project :))

is a job like this possible at home with normal tools?

Hotblack Desiato

42lbs in the front? Way too much. Probably too much for the rear, too, unless you have a passenger and full load. Stick with what the tyre manufacturer recommends for your bike, if you want to experiment don't go up or down by more than about 2lbs at a time.

martco

https://www.boards.ie/discussion/comment/119674325#Comment_119674325

thanks it was just experimenting

I'll know more once I can get that balancing looked at but my gut is not the tyres

mjsc1970

Hi martco. The F800GT forum (seems USA contributions mainly) has this as a point of discussion too.

It seems that this issue is not un- common but most F800 GT owners (myself included) don't seem to experience the issue.

It is strange though. I've no suggestions though unfortunately, apologies

slow

Did you get any resolution?

martco

not yet, I've only been riding locally since I posted...been riding @2.8bar it feels ok but not had the opportunity for a long spin since September so still can't say for sure, maybe a spin down to Wexford when this cauld weather lifts a bit into spring :)

Lorddrakul

The usual advice for pressures, to include occasional 2-up, is 2.5 front and 2.9 rear.

But on a relatively light bike like yours, one up, I'd say 2.3 front and 2.8 rear would be ideal.

goblin59

https://www.boards.ie/discussion/comment/120114484#Comment_120114484

I ride 2.2 and 2.4 bar on the F650gs, theyre pretty similar.

Theres also TPMS on the F650gs as its cast alloy wheels. its happy once its not below 2bar.

Get your wheels balanced might be that

Hotblack Desiato

A high frequency vibration is going to be engine.

Unfortunately there are always going to be some motors with parts at the wrong end of the tolerance range and won't run as smoothly as they should.

Get thicker rubber handgrips?