head shaking

[Anonymous]

quixk question i have a 1983 gs750es..i notice at speed (40 miles per hour)that if i let go of the handle bars there will be head shaking that slowly builds up until i grab the handle bars...any ideas what may be caus ing this?...wheel out of balance?....bad shocks or worn bearings?

[Anonymous]

Tank Slap usually comes from loose steering head bearings. When your hands are on the bars it's fine, remove them and it can get downright violent. Pull the forks, clean and inspect the bearings, grease them and install them with the correct tension. Making them too tight is going to be worse than too loose, so don't go overboard.

Tim

[moto_dan]

Re: head shaking

quixk question i have a 1983 gs750es..i notice at speed (40 miles per hour)that if i let go of the handle bars there will be head shaking that slowly builds up until i grab the handle bars...any ideas what may be caus ing this?...wheel out of balance?....bad shocks or worn bearings?

I too have a '83 gs750es and have noticed the same condition at about the same speed. Here's what I've observed...Usually happens deaccelerating, lower tire pressure increases the problems(try 35 psi, makes it much better), worn tires or too wide of tire makes it worse. Have checked steering head bearings and that is not the problem on my bike. May have something to do with the 16" front wheel.

[Anonymous]

I had an '83 GS550ES that did the same thing way back in late eighties. It also had a 16" front wheel. I was running Dunlop k591s on it. I switched the front to a Pirelli of some kind (don't remember which one, but it had rounder profile and that "old school" ribbed tread on it--maybe a Phantom) and the wobble vanished, hands on the bars or not. The rear tire was changed to a Michelin of some kind and the bike ended up being much more stable.

(Of course, this tire swap may well have just covered up the fact that the bike had misadjusted steering head bearings, too)

[Anonymous]

I'd suspect the front tyre. See the General Discussion forum, there's a similar thread under the heading "shimmy", I think.

[Anonymous]

thanks for the tips...i will check the bearings and have noticed that the front tire needs to be replaced soon. Hopefully it is one or the other