bouncing during turn?

[josepaz2]

Ok so I've recently started to get more comfortable in my turns. Just last week I was on the expressway and was cruising at about 80-85. I leaned left into a turn pretty far (as much as necessary for that turn at the speed), but suddenly I felt the rear tire start bouncing up and down and it was kind of frieghtening because I had never felt that before.

My question is, did I do anything wrong? I mapped out my path of travel, kept vision ahead through the turn. Could it be my suspension settings? I'm not sure exactly how to read it, but on the rear suspension the "1" and the "7" are on the upper portion at the center. Is that ok?

Thanks for your help guys.

-Jose

[woobie]

Any chance you hit some rough pavement? The only time I felt the back end get unsettled was really rough pavement and that time I rode through some gravel mid turn.

As for the suspension CP has posted the stock settings are for a skinny bugger

I was running damping on 3 (top of shock) and spring preload (bottom) on 5 on my stock shock.

[KatanaSoldier]

Any chance you hit some rough pavement? The only time I felt the back end get unsettled was really rough pavement

Me too

[Black_peter]

This is where suspensions prove themselves..
(good or bad) What sounds like may have been happening is that the frequency of the ripples in the pavement was not kept up by the rear tire. If the rear cannot "rebound", that is return the tire as fast as the bump returns, the tire looses contact. It is also possible that with too little damping the tire actually over travels. In fact even one bump can "unsettle" the suspension not just a series.

This may be caused by either (or both) compression damping or rebound damping. A spring (like the one on the rear) will vibrate when shocked (by a bump). Imagine the swing are like a ruler held over the edge of a table. Flick it and it oscillates (vibrates) up and down (even if it was only flicked down) until the energy dissipates. Oil in the shock piston damps the vibration. The weight of the bike damps some of the energy, so separate compression and rebound damping adjustments are best. Not always available on a budget though. The energy by the way is turned into heat. That is why higher end shocks have reservoirs. More oil means it can hold more heat. Hot oil is of course thinner and then squeezes through the damping valve easier lessening the damping..

[josepaz2]

I'm pretty sure I didn't hit a bump or anything, but I do remember feeling some vibration on that same portion of the road when traveling in my car sometime before. However, I only felt the "bumpiness" while in the turn on the bike, as opposed to the entire stretch of road while in the car.

As for the suspension, whats the best way to turn it, and is there two different "wheels" to turn? Dampening/Spring Preload? I don't want to screw it up by using an inappropriate tool. I weigh about 185 with gear and I am about 6'2. So, I'm pretty skinny, but my height adds to the weight.

Thanks for your help guys.

[Black_peter]

THAZKAT's "Suspension Set up Explained"

http://www.katriders.com/forums/viewtopic.php?t=9615

Motorcyclist Magazine's "How-to adjust suspension"

http://www.motorcyclistonline.com/howto/adjust_motorcycle_suspension/

And
Motorcyclist Magazine's "How-to replace a rear shock"

http://www.motorcyclistonline.com/howto/replace_motorcycle_shock/

And
Motorcyclist Magazine's "How-to set pre-load"

http://www.motorcyclistonline.com/howto/motorcycle_suspension_adjustment/

That will get you started..

[steves]

It sounds like you need to make some suspension adjustments. Didn't someone just post a video the other day that showed how to set sag and fork preload?

[md86]

Not how to set it , but it showed how a stocker is set off the showroom and what would need done for different weight riders . And yeah , they said the '06 have fork preload . What gives ? I thought all ANY Kat had on the fork was rebound damping .

[Black_peter]

That would be weird if they got preload the last year.
Maybe the guy just assmumed?