May 06, 2012
In late November 2009, I replaced and upgraded the steering stem bearings to my 2007, DL-650 V-Strom. The upgrade was from the stock bearings Suzuki installs, to a tapered roller bearing system. The article about the work that I did can be found HERE.
Since then, part of my annual “Spring Maintenance Program”, before the riding season really kicks into gear, is to check and test, the steering bearings for proper adjustment. With these bearings adjusted properly, I have found that, the much talked about, “Deceleration Wobble” is eliminated. So is the “twitch” of the handlebars that can occur while riding rough roads at a spirited pace.
(I have also upgraded my front and rear suspension systems. There is some “overlap” in correcting steering issues that occurs between the suspension system, and the steering stem bearings.).
Towards the end of the 2011 riding season, I could tell that the stem bearings of my bike were due for an adjustment. However, that thought got swallowed up by my focus being turned to setting up my garage to build my Sonex airplane. The space where I used to work, on my motorcycle, became occupied by a large workbench that, I needed, for cutting aircraft shapes out of, 4’ wide by 12’ long, aluminum sheets!
With regards to working on the steering stem bearings of my bike, I don’t follow what Suzuki describes in their Service Manual for preparation and, “proper” tensioning of the bearings. That is a choice that I made for myself, after experimenting with different bearing tension settings. Besides, the Suzuki Service Manual was written for servicing OEM steering stem bearings. The bearings I installed in my motorcycle are tapered roller bearings.
The preparation steps that I use to adjust the stem bearings, of my motorcycle, are fairly quick for me to follow. The complete job takes me about 20 minutes to do.
I rolled my motorcycle into my garage, and placed it on its centerstand.
(See that workbench to the left? That is where I used to park my motorcycle and work on it!)
The first thing that I did was to mark the location of my handlebars. It took me awhile to get my handlebars “just where I like them!” I don’t like spending time getting them back to that “perfect spot”, after I move them!
I stuck a piece of masking tape on the handlebars. Using a “Sharpie” marker, I made matching “Sir Marks” on the handlebar risers, and on the masking tape. Now, I had a very quick way to reposition the handlebars back where they fit for me, when it was time to tighten them back down.
Next, I slipped two ratcheting tie-down straps over the supporting beam of the ceiling joists of my garage. I hooked one end of the straps around my handlebars, and the other end around the supporting beam. I added a little tension to each strap.
(Incidentally, the handlebars that are mounted on my motorcycle are stock handlebars. However, I did modify them by welding a stiffening “cross brace” between the grip areas.)
I loosened and removed the handlebar riser caps.
With the caps removed, I could “winch” the handlebar up into the air, and away from the top fork tube clamp.
Then, I loosened the left and right, top fork tube clamp bolts.
Next, I loosened and removed the stem cap nut and locking washer.
I lifted the fork clamp up, and off of the fork tubes. I shoved it forward and out of the way.
Then, I slipped a piece of 2” x 2” spruce between the fork tubes, and up against my crashbars. I did this to keep the front end from turning, while I removed the locking and tensioning nuts from the steering stem.
Using the tool that I made when I installed the tapered roller bearings…..
……I removed the locking nut and washer.
Next, I slid a floor jack underneath the skidplate, and raised the front wheel off of the floor. I made sure that the rear wheel was touching the ground, creating a three point “tripod effect”, between the two feet of the centerstand, and the rear tire touching the floor.
To do my initial stem bearing test, I give the front forks a good shaking. With my hands, I pull forward and push backwards on the fork tubes to see if there is any looseness evident to the bearings. I do this with the front wheel directed forward and also to “full stop left”, and “full stop right”.
There was some movement, which is what I had expected. Doing this test, also let me get a better feel for any “notchiness” in the bearings. If there was, it would be an indication that the bearings were worn, and needed to be replaced.
At this point, I turned my attention to the stem bearing tensioning nut. Using my “Sharpie” again, I placed a “Sir Mark” on the nut; aligning the mark with the groove that has been machined into the steering stem. This mark, gives me an indication of where the bearing tension is currently set at. It is a mark that lets me know that the bearings are too loose at this tension setting.
Then, I switched the piece of 2” x 2” spruce, through the fork tubes in the opposite direction, to “lock up” the front end of the bike.
Next, I tightened the tensioning nut just as tight as I could; drawing the bearing races together. At this setting, I slowly swung the head of the bike, back and forth, to make sure that the bearings were “maxed out”. Then, I tightened the bearings again until I couldn’t move the tensioning nut anymore.
In the photograph below, you can see just how little of a turn it takes, to “max out” the tension of the stem bearings. All it takes is about 1/3 of a turn to go from too loose, to too tight.
A rough guide for me is, to tighten the tensioning nut to a position that is just a tad less then halfway between too loose, and too tight. I am favoring just a hair towards too loose. I will not know what the final tension setting is, until I go for a test ride.
The photograph below illustrates where I chose my initial tension setting to be.
At this point, I needed to button things up, and go for a test ride. To do this, I transferred the “Sir Mark” of the tensioning nut, down to the dust cover of the stem bearing race. I did this so that, when I tightened down the locking nut, I could see if there was any movement of the tensioning nut. It doesn’t take much to change the setting and the performance characteristics of the bearings!
Then, I reassembled the rest of the motorcycle, so that I could go out for a test ride.
When I went for my test ride, I was looking for several things. I put the bike “through its paces”, riding different roads of varying road surface conditions; some are smooth and some are rough. Very rough here in Maine, during the springtime thaw with resulting frost heaves and winter damage!
Here are the things that I look for:
- The infamous “Deceleration Wobble”, (Other V-Strom riders mention this too.), is gone. In the past, when the steering bearings of my bike were too loose, in certain situations, the front end of the bike would wobble. The wobble was not noticeable unless I removed my hands from the handlebars. With my hands on the handlebars, I could feel the wobble. If I removed my hands from the handlebars, the bars would visibly begin to wobble, increasing to a “tank slapper” situation if I didn’t place my hands back on to the handlebars! I can feel and test for “wobble” when decelerating for a traffic light, or to a stop sign. The “decel wobble” would appear at around a 30 – 35mph speed.
- I found another symptom of loose steering stem bearings to be, what I call, “twitch”. Twitch happens when I am spiritedly riding rough surfaced roads. The feedback that I am receiving through the motorcycle’s handlebars is a slight left to right, “twitch”. The back end of my bike feels like it is behaving properly, but the front has a feeling of being “unsettled” and “uncertain” about what it is doing.
- Arm fatigue is another symptom of steering stem bearings being too loose or too tight. An example of arm fatigue from stem bearings being too loose is, if I am in a right hand “sweeper”, I find that I am constantly pushing forward with my right hand, on the right handlebar grip. I am literally “shoving” the head of the bike back up on to the line that I want the bike to follow through the turn. With loose steering stem bearings, the front end of my motorcycle will “fall into” turns too far. With my arms, I have to push the head of the bike back into position on the road. A day of riding like this, and I do feel it!
If the steering stem bearings are too tight, the opposite effect takes place. While in a right hand sweeper, the bike will want to stand up. Now, my left arm is pushing on the left handlebar grip, to force the head of the bike back down to follow my line! Again, a day of riding like this can be tiresome!
- The final bearing related “symptom” I look for is, “weave”. A weaving motorcycle happens at slower speeds, (In a deceleration phase), and is caused by stem bearings that are too tight. I found this happening to my motorcycle, during a test ride, after I had made a bearing adjustment with too much tension to it. As I decelerated from an “out of town” speed, to an “in town” speed limit, the front end of the bike “walked” left and right as I traveled in a straight line down the road. This happened in a 25mph speed zone. When I increased speed, the weave disappeared, but the steering of the bike felt “heavy”. I rode the bike back home, loosened the tension a “touch”, and all was good!
All of the above symptoms have happened to me, while I experimented with different tension settings on the stem bearings. My bike has “twitched”, “wobbled” and “weaved”, (“Wove”?). And, my arms have been tired from either holding the bike up, or pushing it down!
As I illustrated above, there is not much of a space difference between a stem bearing tensioning nut being set too tight, or too loose on my motorcycle. But, testing and retesting, what I need to do to eliminate bearing issue symptoms, and to have a great feeling ride, has been truly worth my efforts!
Fortunately, my test ride for this year, fleshed out a perfect setup for me! No more adjustments for the start of the 2012 riding season!