K75RT weird buzz/vibe at 30mph

[ccarlsonnh]

This one has me stumped... I feel a slight but definite buzz/vibration in the handlebars right at about 30 to 33 mph indicated.  Not related to engine revs... in fact, clutch pulled in with engine at idle, it's the same.  Goes away above and below 30.  Noticeable when slowing down for a corner, etc.  Annoying and, of course, I wonder if something is going awry.  Any thoughts most welcome!

Thanks!

[pdg]

Does it happen in every gear (that you can sensibly select)?

With the clutch pulled in, the gearbox is still being driven by the wheel, so it's possibly in there. Or -- UJ(s), wheel bearings, FD bearings - anything else that moves...

[TimTyler]

If you can replicate the vibration on the center stand, you'll know it's not the tires, forks or steering bearings.

[ccarlsonnh]

Thanks for the inputs!  Yes, different gears gives same vibration.  Tim, I'll try to replicate on the stand... hadn't thought of that. 

[ccarlsonnh]

Didn't feel vibration while on center stand...

[Motorhobo]

 I had a funny vibration once due to loose caliper mounting bolts. It's a long shot but easy to check so might as well get it out of the way.

Wheel bearings need replacing too periodically...come to think of it mine are way overdue.

Maybe also check torque on all bolts that fasten anything to the front end...maybe something's rattling in the airflow. Velocity related would appear to indicate exterior to engine/transmission, at leAst I'd try to rule exterior causes out first. Maybe there's a playing card in your spokes...

[The Mighty Gryphon]

Specific speed unrelated to engine rpm = something is resonant in the running gear

More pronounced when decelerating = front end

My first guess is the steering damper, followed by steering head bearings, followed by the front brake rotors. 

Does it get worse when you apply the front brake at 30 mph? 

[johnny]

tiors wheels steering bearings final drive drive shaft clutch...

j o

[ccarlsonnh]

Thank you all... several things to have a look at!  Will start working through these over the next week or so hopefully ;-) 

[ccarlsonnh]

Have been playing around with this with no real conclusion.  So, took it to my Beemer guru for a test drive this morning.  His take is that there is some tire vibration but not enough to be concerned about.  It really is quite subtle at this point.  If it gets worse, he'll dig into it some more.  So, for now, I just keep riding :-)