Noticed when doing about 90 that my brakes would chatter under load.
Cannot feel a pulse or chatter at lows speeds.
Wonder what it could be? I'm thinking that one of the pistons may not be actuating evenly causing it to chatter.
check disc runout and then for sticky brake parts
YTRAP, G and Joe.... sure gonna miss you guys...
when on the brakes. sucks for shure if yoyu dont have a a dial gage you can use a red sharpy a close hanger and bolt it to your caliper mount on your front fork. spin the wheel teh marker will leave a nice tracer marke on the roter where teh run out is the worst.
I had the same problem. High speed, get on the brakes hard, front end pulsed.
I lived with it for years.
Then the problem went away...
I replaced the calipers with black ones I bought here on the forum, from a bike with much lower miles.
I changes nothing else. Whick tells me the OP is on the right track- the pistons are not expanding evenly. Instead of my "fixing" my problem with a caliper disassembly and clean, I unknowingly "fixed" it with a more healthy set of calipers.