Speed wobble

Noticed on the freeway bike developed a wobble/vibration in the rear at 75-80mph.

New rear tire, new rear wheel bearings, wheel was balanced at the local yamaha shop....Any suggestions? I was wondering about the shaft, but was not sure where to start checking

 

First, it's very hard to diagnose remotely because there always seems to be some piece of information that gets forgot or is missing but you call it a "wobble/vibration" so I'm guessing that this isn't something that causing your bike to change track?

Have you put it on a centerstand or jack yet? You need to get the rear unloaded so you can begin to evaluate what you have. I am no shaft expert but I'd want to check anywhere that they may have disassembled anything concerning the shaft drive. Then the shock/s mounts to make sure that the rubber dampers are in place and are the correct ones even though they sohuldn't have touched them. Then on to the wheel itself by checking for any lateral play, there should be......none! Did they replace all three bearings including the drive hub and wheel or just the wheel? If they didn't fully set them, they will cause drag and resulting vibration but you won't be able to tell without taking the wheel apart. Don't forget to check the actual axle nut for tightness.....I've seen loose nuts from service departments before. Finally, check to see that the rear wheel is correctly aligned with the frame/front wheel. Laying on the ground 10 feet behind the bike will give you a close approx and you can get closer yet using the string method but usually anything far enough out for you to notice will be easily seen from the 10' mark.

jeff

 

I can get booked at 61mph, damn glad i don't havta do 75 - 80 to keep up... how's th front tire for wear/pressure? Th swingarm bearings can cause a wobble as well they may need tensioning, so can head stem bearings, worn and/or loose..more things to check. In my world a wobble at those speeds is a very bad thing..

 

is this the HARDTAILED bike?

 

it is the hardtail. Never had it before the vibe before... I have done the string test tonight and everything is in alignment. I thought about the swingarm.

 

Sure you diddnt just hit some tar?