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Instability at highway speeds

Posted: Mon Oct 23, 2017 7:30 am
by Bryced1
Got another question on my new (to me) 95 intruder 800.

Bike runs great and feels stable at low speeds (up to 60), but at highway speeds (around 60-70), the bike begins to feel a bit unstable. Just like it is loose and "wiggles" slightly in the lane. Being a new rider, I am not sure if this is normal or if something this wrong.

Potentially a rear tire alignment issue? or a steering head bearing? Or does it sound like someone just not used to the bike?

I am planning on going through the bike with a fine tooth comb this winter and servicing a lot of components, want to know what I should add to the list to help remedy this. Thanks!!

Re: Instability at highway speeds

Posted: Mon Oct 23, 2017 8:13 am
by WintrSol
Start with tire pressures. If the tires are over 6 years old, replace them, then try to find the recommended pressures given by the manufacturer. I last had Avon tires on my 800, and the pressures were a few pounds higher than that stated on the ID tag; running the tag pressures made it a bit unstable.

If you have access to a lift, get the front wheel off the ground, and tie the bike down. Tighten all bolts to spec first, top to bottom of the whole steering assembly. Grab the front wheel at top and bottom, and try to shift it by pushing/pulling the top while doing the opposite at the bottom - this should reveal looseness in the axle bearings. Spin the wheel, too, and listen for anything but smooth running bearings; you could have a slightly warped rotor, which should be visibly wobbling when spun. Pass that test? Then try pulling just the bottom of the wheel from side to side, and feel for any motion in the forks; if you feel any wobble at all, the steering bearings may need adjusting.

After checking torque at the rear suspension and axle, try moving the rear wheel around in a similar manner, though the wheel bearings may be hard to assess because of the shaft drive.

Re: Instability at highway speeds

Posted: Mon Oct 23, 2017 8:47 am
by navigator
Totally agree on adjusting your air pressure. change by a few pounds till you find the sweet spot.
I run Pirelli MT66 tires at 36psi Front and 38 Rear,
your results may vary.

Re: Instability at highway speeds

Posted: Mon Oct 30, 2017 6:30 pm
by Forge
Mine was wobbly when changing lanes. New tires cured it completely.

Re: Instability at highway speeds

Posted: Fri Nov 03, 2017 6:31 am
by Bryced1
Update: new tires front and rear and she is much more stable. Thanks!

Re: Instability at highway speeds

Posted: Fri Nov 03, 2017 7:32 am
by Forge
Bryced1 wrote:Update: new tires front and rear and she is much more stable. Thanks!
Glad it's better. Now get out and enjoy her! :putput: