I'm no racer, mostly ride for commute and occasional recreation, but I recently have noticed a problem with my bike. When I get going at freeway speeds, my handlebars start to shimmy if I lean the bike too far either direction. It may be my imagination, but it almost seems worst when I lean to the right?
taking a 50mph curve at 65 feels downright scary, when on a motorcycle (at least in Salt Lake area, Utah) these shouldn't be a problem at much higher speed than that.
Does anyone have any ideas? I was planning to make a trip to vegas at the end of the week (weather permitting) but I don't dare unless I know whats wrong.
There does seem to be something rattling (very high frequency) on my handlebars when I accellerate, but I don't know if that's related or not.
Kerry and I replaced the fork oil and changed the seals a week and a half ago or so. Might that have caused this?
My first suggestion is that you check the bolts that secure the forks, fender (fork brace), and the front wheel. Also, check your tire pressures. You might also check front/rear tire alignment. All of these could cause the symtoms you've described. :cheers:
Could it be that your forks are no longer "balanced" do to your maintenance? One side softer than the other and it's allowing the tire to twist to one side? Since that's all that has changed. Or as said earlier, you didn't put everything back together quite right.
How big a difference in the amound of fork oil would it take to produce that effect? we did have a hard time getting one side there, and I don't think it was exact, but I think it was close...
I checked the bolts, they seem to be tight, unless I'm missing one somehow.
the fork oil is the only think I know to check, and that's going to be a bit of a pain, methinks.
Difference between fork legs shouldn't matter at all since they are tied together. IIRC, at one time, BMW had a model which used one leg for damping and the other leg for the spring.
I would check the condition of the steering head bearings and check the balance of the front wheel.
Yeah- you may want to drop 10 bones and have the tire rebalanced- that would be a good suspect to rule out. If it turns out the wheel is balanced, then you already have the wheel off and can dig right into the front wheel bearing.
If I was a betting man, it happened when you dismantled everything and put it back together; not the fork oil. I remember a service article in Cycle World or another magazine years ago that discussed this. The gist of the article was that the wheel/fork assembly needed to be tightened down sequentially, like lug nuts on a car or cylinder head bolts. To eliminate the possibility that something was torqued down improperly and threw fork alignment off, I'd loosen everything up and slowly tighten everything down again; starting with running everything down just finger tight, then going back and forth until everything was snug. You mentioned handlebar rattle; did you check the clamps, and the bar itself for cracking? :cheers:
I have experienced this sometimes in high speed freeway interchanges. It occured to me one day that my weight had transfered so that I was putting more weight on the bars and gripping them. I tightening up my grip on the tank with my legs (loosening my grip/weight on the bars) and my wobbly turn smoothed out completely. I'm not talking about a smooth road here either :)
something to consider next time you are going through a turn. I say this because you and Kerry just serviced your forks
Also check if your forks are aligned. If one is higher in the triple than the other, your axle will be crooked making your wheel have runout
*whew*. glad it's not the fork oil. =] that probably would have really been a pain to troubleshoot.
I solved the mysterious rattling sound... I added a small key to my motorcycle keychain, and I realized tonight when I rode that the extra key was doing the rattling. :oops: :x :roll:
I am a pretty tall guy (6'1"), and having put a katana shock on the back of the bike, I do tend to lean forward more than most probably do. If that would cause it, maybe I should try one of the stretches of road where I had the problem with my backpack on, concentrating on staying off the handlebars. My backpack (weighing probably 40lbs or so, since it has a 17" laptop in it + accessories) seems to counterbalance, and I've noticed when I wear it while riding it takes a lot of strain off my wrists... and transfers it to my shoulders. :lol:
I will need to try that this week, and see if that solves the problem. I hadn't considered that my own weight might be the problem. If that doesn't work, I'll try the balance thing when my new rear tire comes in... just do 'em both at the same time, I guess.
Thanks, all. I'll keep you posted.
Eliminate the simple things first, tighten everything and check the tyre preasures they can cause a wobble effect, 33psi front 36psi rear for solo riding, it's probably printed on the swingarm. Also look for tyre wear.
Richard, I'll try to drop off my Haynes manual in the next day or two. Chapter 1 has at least two relevant sections - one on checking for freeplay in the steering head bearing (and how to adjust it) and another on suspension checks (smoothness of fork compression, side-to-side freeplay of the swingarm, up-and-down freeplay in the rear suspension bearings). The first section is designated with "2 wrenches" out of 5, and the second section only rates a single "wrench".
Looks like I'll need to loan you my torque wrench, too.
Meanwhile, here are a couple of blurbs from the first section I mentioned:
QuoteIn extreme cases, worn or loose steering head bearings can cause steering wobble - a condition that is potentially dangerous.
QuoteHaynes Hint: Freeplay in the fork due to worn fork bushings can be misinterpreted for steering head bearing play - do not confuse the two.
I can only assume that a check for "worn fork bushings" is described somewhere. Chapter 5 looks like the best bet - the same place we found the instructions for disassembling the forks.