55 MPH Vibration ??

[GTGS]

Since I bought my bike a year ago, I have noticed that at around 55MPH I can see the forks pulse up and down like the tire is out of round. There is nothing noticeable till you hit 55+. I replaced the fork seals a few weeks ago and that improved it slightly. I have had the front wheel balanced and the bearings appear to be good with smooth rotation and no binding. Everything is tight and properly torqued. The PO had new tires installed just before I bought the bike and like i said it's always done this. There is a slight vibration in the bars at 55+. Any Ideas?

 

[bobthebiker88]

a bent/out of true rim will cause something like this, as will tires that lke you say, are out of round. worth looking at.

 

[GTGS]

I know you can check the rim with an indicator but how would you check the tire for out of round?

 

[Guest]

I know you can check the rim with an indicator but how would you check the tire for out of round?

Same way....place the indicator tip just off the front profile of the tire & give it a slow spin.....eyeball & check for contact. While checking these things, it would probably be wise to double check that the wheel is in fact balanced.

 

[KGB]

Fork fluid level? If they're air forks, are they balanced, as in the same
air pressure in both sides?

 

[TheCafeKid]

Did you put the front end back together following the manual? Tighten everything in order, and to spec? If the wheel is true, you could have some fork bind going on there.. Then again, vibration in the bars at certain RPM could also be a motor in need of a valve adjustment, or carbs that need balanced..