under moderate to heavy braking, i'm getting a pretty significant front end chatter, and it's killing my lap times. it happens with the clutch pulled in or not pulled in, and regardless of engine RPM. i'm pretty sure its coming from the front end. it happens with the bike upright, and i can feel it when the bike is leaned over(trail braking) and i'm on the brakes. the concern began after i attempted to replace a fork seal on my own. the fork seal was successful, but i couldn't adjust my rebound dampening. screwed the pooch on that one...however; since then, i've gotten whole new fork internals from K-tech installed by a reputable professional suspension shop, so whatever i messed up in there has been replaced. so far, i've checked my wheel bearings, there is no play in my steering stem bearings, i have brand new EBC rotors, vesrah RJL pads, Galfer SS lines, Brembo RCS19 MC, happens with 2 different front tires, all front end bolts are torqued to spec(axle nut, clamp bolts, triple clamp bolts, caliper bolts) I had a professional suspension shop install K-Tech Fork internals, as well, so i can only assume he checked fork bushings for wear. i'm very confident that there is no air in my brake lines, and i'm running RBF600 DOT 4 fluid. also, the fork tubes are even in my triple clamps. Even though my bearings FEEL fine, i'm aware that to properly test a bearing, it has to be under load. and seeing as how this is a track bike, track days are expensive and testing a bearing under load is time consuming and costly, so i went ahead and ordered new streering stem bearings and front wheel bearings. is there anything i'm overlooking or maybe a process i could have messed up during front end installation or something? this problem is driving me nuts and i'm not willing to push myself on track because of it, so i'm not progressing as a rider.
In general front end chatter is caused by lack of rebound damping. Although it sounds like you have had everything refreshed,, have you had a track side suspension tuner setup your stuff? If not I would highly recommend it and it is well worth the money. They will do a baseline setup (sag etc) and then you take it out and see how it feels and work from there.
From your description I'm questioning the wheel or the rotors if it's only under braking. I know you said you have new rotors but they should be checked that they are true if the chatter is that bad. There is guy name Will (Will's Rim Repair) in NC who does a fantastic job checking and repairing bent things that spin. If you have the front end up in the air and spin the wheel slowly is there a spot where the rotor(s) drag more on the brake pads / caliper? if so remove one caliper and spin the wheel slow. Does it snag or spin slower still? Remove that caliper and put on only the other caliper. Try each individual caliper to try and determine which rotor might have a bend. I know you said they are new but they bend extremely easily if one is not careful with either tying the bike down and the front wheel is in a chock or the person changing the tire is careless. Just throwing some ideas out at you because I've dealt with the same issues. If it's not the wheel or the rotors it could be a suspension issue but the fact you said it happens under "moderate to heavy braking" points right towards the brakes. Will can check rotors and wheels and does a great job. willbabb@hotmail.com phone# 864-329-7671 Wills Rim Repair 416 Winding Brook Ct. Greenville SC 29617