Bouncy front end

DeanCol1 · Jul 13, 2016

I'm getting a lot of bounce and hopping from the front end at roughly 60mph and above in last few months.
I had changed the fork seals and upgraded the springs with Sonic 1.2s back in January of this year and really liked the firmness up front.
It has only been recently (the past month) that I've been experiencing this bounciness.
The bike is an 04 with almost 100k on it; I keep the tire pressure set at 42psi.
Would a new rear shock/rebuild tame some of this bouncing?

dduelin · Jul 13, 2016

Tires will wear out of balance sometimes or throw a balance weight. Checked dynamic balance since it started hopping?

dwalby · Jul 13, 2016

In addition to the advice about checking for missing balance weights, is there any chance you'd run over any sharp bumps lately that could have knocked your rim out of true? I'd take a close look at the rim and tire to see if it reveals any clues. Put the bike on the centerstand, elevate front wheel, and spin. Look for runout on the rim, and check the tire for consistency as it rotates. Perhaps a belt slipped or something that distorted the tire profile?

And to answer your question, no, this doesn't sound like anything that would be cured by doing anything to the rear shock.

Igofar · Jul 13, 2016

Also check the preload adjuster to see if your fluid is missing or low.
Wear or cupping on the front tire may also cause what your describing, as well as wheel bearings on their way out.

DeanCol1 · Jul 13, 2016

All sounds like good advice to me, I will check out these suggestions. Thank you ST forum!

DeanCol1 · Jul 26, 2016

UPDATE: New Michelin PR2 and adjustment to the dampening seemed to cure about 85% of the problem, but still seems a little bumpy. I will need to check to seem if my wheel is true.

DeanCol1 · Aug 27, 2016

ANOTHER UPDATE: I was still getting having a problem with the bouncy/shakey feel. So I kept looking into the issue and found where high mileage STs have preload problems due to oil leak in reservoir. Preload was something that never messed with since I bought the bike but I twisted the knob and it felt flimsy. So, with the help of the forum, I pulled the knob, filled the reservoir with fork oil and discovered that there is now pressure in the knob as if it's actually doing something by firming up the rear suspension. I went for a ride and noticed a huge difference. Can't believe that I had no preload in the rear all this time, new lesson learned.

jmcarruth · Aug 27, 2016

DeanCol1 said:
ANOTHER UPDATE: I was still getting having a problem with the bouncy/shakey feel. So I kept looking into the issue and found where high mileage STs have preload problems due to oil leak in reservoir. Preload was something that never messed with since I bought the bike but I twisted the knob and it felt flimsy. So, with the help of the forum, I pulled the knob, filled the reservoir with fork oil and discovered that there is now pressure in the knob as if it's actually doing something by firming up the rear suspension. I went for a ride and noticed a huge difference. Can't believe that I had no preload in the rear all this time, new lesson learned.

If I were you, I would go ahead and replace the steering head bearings with good Japanese roller type from CBR Bearings, if you have not already. Also, if that is the original shock, it is way overdue for rebuild or replacement.

Al Gully · Aug 27, 2016

Dean,
Do you have any plugs in your tires. I just had a mishap on my V45 Sabre as it had a gummy worm in the rear tire.
The rear tire started a bulge just across where the plug was. Was 100 miles away from home when I noticed it.
I guess the screw that I picked up cut through the radial cords and weakened the tire in that area.
The bulge was hard to find as it did not stick out to far on the tread. What gave it away was the sipes in that area of the bulge were a lot wider than the other sipes.
Limped home and bought 2 new tires for the bike. They arrived yesterday.
Long story short, no more plugged tires for me.

Bouncy front end

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