Shakes on FXR150...

[SuperDave]

Was wondering if anyone knew what causes the following

I have noticed that if I am going at say about 60kph and put the bike into neutral and then use ONLY the front brake to slow down I get a shaking/jittering feel through my steering. This movement feels as though its going back and forward. The movement does not make the bike unstable but it is certainly noticable.

I have recently had my steering head baring replaced as well a new straight front disk fitted. My front brakes were also cleaned. I don't find this a major problem as I always use my gears to slow down as well as the front brake and a bit of the rear. The shaking only happens when I put the bike into neutral and slow down with the front brake alone.

Would just like to know what this shaking is a result of?

Thanks.

[bugjuice]

well for one, don't put the bike in neutral to slow..
Check the tightness of everything. Sometimes head bearings settle in a bit more than they are first done. And check the disc bolts and axle etc. I'm betting the head bearings are just easing in..

[James Deuce]

That's the natural oscillation frequency of your steering. Don't sweat it. EVERY bike has a speed that the steering will oscillate by itself.

[SuperDave]

That's the natural oscillation frequency of your steering. Don't sweat it. EVERY bike has a speed that the steering will oscillate by itself.

Wow! I was watching the discovery channel yesterday and it had these people jumping on a concrete beam. Anyways the beam didn't move at all until they made the 6 or so people jump at the same natural frequency of the beam, then the damn thing started moving a good few cms or so up and down!

[SuperDave]

well for one, don't put the bike in neutral to slow..
Check the tightness of everything. Sometimes head bearings settle in a bit more than they are first done. And check the disc bolts and axle etc. I'm betting the head bearings are just easing in..

Thanks for that. Don't worry, It was a controlled test of how the front brake was performing after the new straight disc was fitted.

[erik]

Wow! I was watching the discovery channel yesterday and it had these people jumping on a concrete beam. Anyways the beam didn't move at all until they made the 6 or so people jump at the same natural frequency of the beam, then the damn thing started moving a good few cms or so up and down!

I vaguely remember one of my lecturers talking about when there was a huge march across the harbour bridge, that because lots of people were walking in pace and it was at the resonant frequency of the bridge, it made the bridge sway up and down.

[Flyingpony]

I have noticed that if I am going at say about 60kph and put the bike into neutral and then use ONLY the front brake to slow down I get a shaking/jittering feel through my steering.

Bit of a worry there by slipping it into neutral at 60km/hr. I'm in 4th or 5th at that speed.
Don’t know about steering head bearings but from car experience, new front rotor could be the cause. It’ll feel different. Hope you got new front brake pads at the same time. Maybe it need time to settle – does the front brake rub when pushing it?

Could your chain be slack or kinked? That'll give a similar sensation.

How many km have your travelled?
I’ve nearly done 12,000k and the only work (excluding services) mines had is chain & sprockets, spark plug, battery and various lights.