I recently had a valve stem failure on the road which required the use of Fix a Flat on the front tire. I took it to the bike shop and the merely pulled the tire away from the rim by the valve stem and stuck a new stem in it. The bike seemed ok but I didn't run it hard for several weeks(because I didnt ride it)But when I did I noticed a severe vibration at 115mph+. I took it to the bike shop and they broke down the wheel, cleaned the crap out, re mounted and balanced it. Now the high speed vibration seems less but I have a definet wobble in the bars at 50mph-75mph, then it changes to a vibration over those speeds. If you take your hands off of the bars at 55 mph, you can watch the bars wobble as if to go into a tank slapper!!but then when you slow to about 40 it disappears. I watched him balance the tire, it needed 1.5 on one side then after respinning the balancer it zeroed out. Do you guys think The wobble/vibration is due to incorrect tire balance on the front or possibly something else?? I am not even going to ride it until its fixed but I don't want to take it to a dealer. Any Ideas? Johnny, what you think? Both tires are new 56J's with about 800 miles. I use this bikeshop a lot for tire mounts as does alot of other people here. I had a ZX11 do exactly the same thing with a fairly new tire and the same shop balanced it too. Thanks for any help!