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Bad Headshake at 40MPH
Posted: Fri Jun 19, 2015 9:18 am
by Rebel
I had to bring "Mr. Thirsty" (my Dodge truck) to work this morning. My bike developed almost a "tank slapper" at about 40MPH this morning. This has been getting worse for a while now, and I attribute this to my fork seals leaking, and an imbalance of fluid. Hopefully the seals I ordered last week should be in the mail today so I can do the job over the weekend.
Re: Bad Headshake at 40MPH
Posted: Fri Jun 19, 2015 10:52 am
by bbelk
The first place I would look is at the front tire. It doesn't take much non-uniformity in the tire to do this. I think forks can do it, but I have gone quite aways on bikes with leaky seals without getting into the problem.
Re: Bad Headshake at 40MPH
Posted: Fri Jun 19, 2015 10:58 am
by robert
Adjust steering head bearings.
Re: Bad Headshake at 40MPH
Posted: Fri Jun 19, 2015 11:00 am
by Rebel
Thanks, but my tires are Pirelli Sport Demons, and are fine. I am more suspect to steering head bearings, which I will check when I am installing my fork seals. I will also check and lubricate my wheel bearings while things are apart.
Re: Bad Headshake at 40MPH
Posted: Fri Jun 19, 2015 9:45 pm
by SteveD
Worn tyres, tyre pressure too low, head stem bearings, wheel bearings, loose axle nut, overloaded, right caliper was hanging up 
...sometimes it's a process of elimination. Some are easier, quicker and cheaper than others to fix. I hope you get lucky.
Re: Bad Headshake at 40MPH
Posted: Mon Jun 22, 2015 8:35 am
by Rebel
My right caliper was hanging up, so problem solved!!