Tightening the steering stem bearings
For that past little while I have been noticing a thunk and a quiver in the steering when going over less than smooth road surface and small bumps. Even little ones like the transition from the gutter to the driveway. The quiver in the steering and handlebars was subtle, very similar to when you pet the dog and it gets tickled and tenses it's muscles under your hand. If that makes any sense to anyone...
It seemed to me that the most logical cause would be loose steering stem bearings. I checked for slop using the method in the service manual of lifting the front tire off the ground and grabbing it by the axle and pushing/pulling in all directions. It felt tight, no play in any direction. The SM also called for holding the front brake and rocking the bike forward and backward (with the front wheel back on the ground of course). Still felt tight. I started to wonder if it was some other important bolt or something in the front end loosening up and flopping around over the bumps.
I eventually went so far as to order a spring scale that reads between 0 and 10 N. Not that it is the highest quality equipment and likely never calibrated, but hopefully better than nothing... So when it arrived I put the Vee2 up on the center stand, had a kid sit on the luggage rack to get the front wheel off the ground and went about measuring the force required to move the steering as directed in the service manual. The specification in the manual is between 2N and 5N. I was measuring right near the 2N mark, so I figured it was on the low end but still in spec.
Today on the way home, I was stopped at a light with my right foot on the brake and my knee touching the tank. I smacked down on the top of my leg and felt a shimmy / wiggle go through the whole bike and also felt it in the handlebars. I had been thinking about the possibility of the 2N being low enough that even bearings that are too loose will still require 2N to get them moving, so I pulled the tank when I arrived home and checked every bolt and mounted gizmo for looseness. After not finding anything loose or floppy, I started the procedure for tightening the steering bearings.
As I tightened the steering stem bearing nut, it didn't seem to make any difference in the felt resistance of the steering stem. However, when I had tightened it to a point where I figured that must be enough, maybe too much, I put the spring scale back on it. It was measuring between 4N and 5N, so I backed it off to 3N. After setting the lock nut I measured again and it had firmed up to 4N. This was "near~ish" the center of the spec so I left it as is.
A quick test ride around the neighborhood and to the gas station to fill up the tank showed that the thunk and quiver were completely gone.
Maybe the minimum allowed 2N is too low, or maybe my spring scale is a piece of crap... Either way the thunk is gone and the steering doesn't feel any bit of too tight. Here's hoping it isn't...