checking a rotor and cleaning

I'm trying to diagnose a brake chatter under very hard application (seems fine under heavy to hard application - just chatters when really pushed).

How do you accurately check a rotor to see if its straight? I dont have any calibrated instruments to see if its slightly off.

It doesntave any of the signs of a badly warped rotor (I've had those before). It looks straight when put on a flat surface.

I plan on thoroughly cleaning the rotors and putting in new pads in hopes of eliminating the issue. Suggestions on cleaning the rotors beyond just brake cleaner. Bead Blasting, brillo pad?

I may also check the stearing head bearings. Front tire is in decent condition (no cupping etc) and I know the rim is good.

Any other suggestions prior to spending big $$ for new rotors.

FYI - its a 01 F4i with 15K on the clock.

Thanks in advance for any input.

is it rotors? i had chatter going into turn 7 @ the last AFM sears race and a couple clicks in compression up front helped w/ that. i know it's a bandaid fix and i'll need to get the front redone but it helped...

I dont know Calvin. I think I need to play around with it this weekend as I really cant make it happen in commute mode - have to riding pretty hard.

The forks were just redone at aftershocks about a month ago - so I suspect something else.