Bad Headshake at 40MPH
Bad Headshake at 40MPH
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.
AMA Charter Life Member
Now: 1983 Yamaha XV-920MK Midnight Virago with Factory Touring Package
Then: 1987 K-75S, 1988 R-100RS,Triumph T-140D, Harley FXDB Sturgis,Triumph Speed Triple,Triumph Bonneville, Moto Guzzi Norge, Yamaha FJR-1300, Victory Vision...
Now: 1983 Yamaha XV-920MK Midnight Virago with Factory Touring Package
Then: 1987 K-75S, 1988 R-100RS,Triumph T-140D, Harley FXDB Sturgis,Triumph Speed Triple,Triumph Bonneville, Moto Guzzi Norge, Yamaha FJR-1300, Victory Vision...
Re: Bad Headshake at 40MPH
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.
1975 R90/6
1979 R65
1979 R65
Re: Bad Headshake at 40MPH
Adjust steering head bearings.
Re: Bad Headshake at 40MPH
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.
AMA Charter Life Member
Now: 1983 Yamaha XV-920MK Midnight Virago with Factory Touring Package
Then: 1987 K-75S, 1988 R-100RS,Triumph T-140D, Harley FXDB Sturgis,Triumph Speed Triple,Triumph Bonneville, Moto Guzzi Norge, Yamaha FJR-1300, Victory Vision...
Now: 1983 Yamaha XV-920MK Midnight Virago with Factory Touring Package
Then: 1987 K-75S, 1988 R-100RS,Triumph T-140D, Harley FXDB Sturgis,Triumph Speed Triple,Triumph Bonneville, Moto Guzzi Norge, Yamaha FJR-1300, Victory Vision...
Re: Bad Headshake at 40MPH
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.
Last edited by SteveD on Mon Jun 22, 2015 6:40 pm, edited 1 time in total.
Cheers, Steve
Victoria, S.E.Oz.
1982 R100RSR100RS supergallery. https://boxerboy81.smugmug.com/R100RS
2006 K1200R.
1994 R1100GS.
Victoria, S.E.Oz.
1982 R100RSR100RS supergallery. https://boxerboy81.smugmug.com/R100RS
2006 K1200R.
1994 R1100GS.
Re: Bad Headshake at 40MPH
My right caliper was hanging up, so problem solved!!
AMA Charter Life Member
Now: 1983 Yamaha XV-920MK Midnight Virago with Factory Touring Package
Then: 1987 K-75S, 1988 R-100RS,Triumph T-140D, Harley FXDB Sturgis,Triumph Speed Triple,Triumph Bonneville, Moto Guzzi Norge, Yamaha FJR-1300, Victory Vision...
Now: 1983 Yamaha XV-920MK Midnight Virago with Factory Touring Package
Then: 1987 K-75S, 1988 R-100RS,Triumph T-140D, Harley FXDB Sturgis,Triumph Speed Triple,Triumph Bonneville, Moto Guzzi Norge, Yamaha FJR-1300, Victory Vision...