Front end behavior during track days????

[NIN]

I have done a total of about 8 track days and as I have progressed I have noticed that on one level slow right hander (35-45 mph) it causes the front tire to "shutter". The bike remains stable and the movement appears to be vertically within the suspension, but this is quite unsettling. I am off the brakes completely by the time this occurs and am transitioning to applying throttle. I am hoping to put in stiffer springs and oil up front before next season, but am unsure what is causing this. I am about 170 lbs with out gear, and have the rear shock set to 1 click above stock. Thanks for any advice.

 

[motojoe122]

Is your back wheel aligned properly? I noticed my bike did what you described, I would get a slight head shake under power. I checked my alignment and found it to be a little off.

 

[Cali rider]

Steering head bearings might be loose? Front tire pressure might be too high? How many track days do you do on one set of tires? They get harder after each session and will become unstable very quickly, personal experience told me to use new tires every other track day regardless of wear.

You might try a thicker front fork oil AND less volume of oil, like 5.5" from the top of the tube.

Just a few ideas, I'm sure there might be other reasons.

 

[SovietRobot]

I can't comment on track days, but a few things to consider are like Cali rider said, steering head, tire pressure, and also wheel bearings.

If it feels like there's absolutely no resistance when you turn the wheel from left to right, and just barely pushing on the handlebar makes the bike turn in rapidly, it might be too loose. I know my steering head nuts aren't tight enough and the same symptoms happen.

 

[FinalImpact]

OP - you never mention how many miles on the bike, but if I were a betting person, I'd guess that getting on the gas is unloading your compromised springs. At the angle you describe, it sounds as if the springs are not keeping the tire in contact with the track causing the sensation you feel.

If nothing else pans out, bearings, tire condition/replacement/air-adjust, I'd opt for those springs sooner than later.

Perform this (View attached) and if the sag cannot be corrected, get some springs and hardware to set it properly.

TopEnd.tv - Tech Tips - Setting Suspension