K75 doesn't seem as smooth as it should be

[F14CRAZY]

I think I'll do the next valve adjustment myself but there comes a time where I say F it and pay the two hours to have it done

[BrickMW]

Sorry to dig up old issues...consequence of the search function I suppose.. but...


Are you saying that the valve clearance job you had performed by your local dealer solved this vibration? For sure they didn't do anything else? What valve adjustments were made?


Reason I ask, I just revived my K75c from a 4 year hibernation. I've done all the "usual suspects" fuel system / all fluids / brakes / tires etc...


This past weekend I checked the valve clearances, and all were loose, and according to Chris Harris, nothing to worry about or try to correct.
All intakes were 0.20-GO & 0.25-NO GO
All exhaust were 0.30-GO (this was the thickest I had, and at the time wasn't concerned with "loose")


This bike was butter smooth before hibernation, and I often rode hundreds of miles without the slightest buzz or vibration in the bars. I have changed to "S" low bars and at first was blaming this condition on that, but it seems to be getting worse and is definitely unbearable. A 30 mile ride has my hands and forearms feeling like I've been running a cheap chainsaw all day. :nono


I also believe it has to be in the engine because it is only present with RPM. I can cut the motor at 90 MPH, clutch in or in N, and the ride goes to glass. It gets worse as it warms up and I feel a "roughness" in the engine at idle after 15-20 mile warm-up.


I have no reason to suspect any part of the clutch or trans as they haven't been disturbed other than fluid change, and an issue like this caused by it sitting dormant would certainly be documented by now... wouldn't it??  :dunno

Everything else has been exactly as expected, runs great, starts great, MPG on par, shifts smooth, pulls strong... all normal. Popped the fuel pump fuse once the other day after a 60 mile ride, others have also reported this after installing an EME replacement pump, so I haven't panicked over that yet.

So, back to my original inquiry, could loose valves be the issue? I'm doubtful, but if that's what cured F14CRAZY's buzz, I'm ready to reconsider I suppose... Meanwhile, if I feel the need to punch a cager's mirror or window, my hands will be numb and I won't feel it till later. I always try to find the "up" side of adverse conditions... :hehehe

[Martin]

Try running 2 bottles of Techron through your system. Half a bottle per tank do this consecutively.
Regards Martin.

[The Mighty Gryphon]

First off, it's odd that the valve clearances have loosened up.  The normal situation is a closing gap as the valve seats itself further into the head.  Wide clearances can interfere with air flow through the engine. 

I agree with Martin on the Techron.  Four years is a long time to lay up an engine with fuel in it.  Along with the Techron, I would run the engine as much as possible one gear lower than you normally would, especially 4th.  I would not use 5th at anything below 60mph while you are running the Techron through it.  It's quite possible you have a stuck ring that will loosen up at higher rpm.

Additionally, I would balance the throttle bodies.  I know my bikes run smoother when they are balanced. 

[rbm]

Sync the throttle bodies.  If they are out of sync, then vibration is inevitable.

[F14CRAZY]

I never felt that any one improvement that I tried made a noticeable difference...adjusted valves, balanced throttle bodies, replaced the clutch parts and staggered them, different tires, bar end weights (only tried cheap ones, not the stainless pounders johnny has).

But I'm fine riding my K75 long distances now. The numbness was coming from the handlebar position. I rotated them a couple degrees (forward I think) and that made all the difference between having numb hands and not.

I've put almost 50k miles on the bike since I bought it. I figure if there was a vibration that was "bad" then something "bad" would have happened by now