Hey guys,
So after doing all my mods to my bike, I feel as if the front end bounces when going between 30 and 45 mph, any faster or slower it isn't very noticeable. You think the heavier tires will cause that? I have also done a bunch of wheelies in the past and I was just thinking the shocks are just on the soft side. Is it possible to adjust shock stiffness? I can't seem to find it in my manual and haven't seen anything about it.

 

Sounds to me like your front tire needs balancing...

 

Tire is balanced, forgot to mention that. If it was out of balance I would feel it extremely at higher speeds, but yeah, tires are balanced but still does it.

 

Not always true. The vibration will tend to occur at road speeds where the oscillation of the imbalance matches the suspension's resonant frequency. Therefore, vibrations often disappear at higher speeds.
How long ago were the tires balanced? As they wear, they usually go back out of balance.
Not trying to 'be right', just wanting to make sure your'e not falsely discounting a cause of your problem.
If it's *definitely* not an imbalance, I'd start checking for worn steering & wheel bearings. Steering bearings are especially vulnerable to wheelie damage...

 

Yep, it's likely natural frequency at that speed range. My 'S with Trackmaster II front has a natural frequency bounce around 45-50 mph, shows up even with freshly balanced tires. I avoid riding at that speed like the plague. The thing with natural frequencies is that even the smallest forcing function will result in large displacements of the system.

 

1+ on a ballance issue, been there done that.

 

So is it possible to increase the stiffness of the front shocks?

 

You'll need to replace the springs. Moto-pro sells them for our bikes. The owner was great to deal with. I replaced them in about 30 minutes. It's a good bang-for-the-buck mod, well worth the investment. Just make sure to get the right springs for your riding weight.

 

His site only lists the KLX250S there is no option for the SF. Is there any difference?

 

Yup, S has longer travel & softer rate than the SF. Stiffer springs may help reduce the symptom of your problem, but won't fix it.