Is there any way to tell which one is warped without a dial indicator? Perhaps taking off one of the calipers and zip tying it to the fork and driving around slowly a little? Would the braking system actually stop the front wheel with one of the calipers removed? Not disconnected, just unmounted.

 

Jack the bike up and spin the wheel?

 

Plus One !

Nothing worse than a bent rotor, especially on front. Our Ultra came with one rotor not flat, and was not replaced under warranty as it was "within tolerance." It made it darn near impossible to come to a complete stop using the front brakes without becoming unstable from the "grab-release" effect of it.

 

I had to replace a rotor on each of my road kings..one was under warranty..the service tech said to me and the wrench ..bet its the right side and it was..known problem or lucky guess?

 

My Road Kings front rotors were also pulsing to the point my wife was asking me "what are you doing". Changed all three rotors to Performance Machine, all is well now.

 

You cannot "unmount" a caliper and activate the brakes. Unless the caliper piston press the pads against something solid the piston would pop out of it's bore and leak all the fluid out.

As noted, jack up the bike and spin the wheel. If you don't have a dial indicator, a rough way to tell is fix a pointer near the rotor and spin the wheel. The run out in the rotor will be obvious as the rotor moves near and away from the pointer as it spins.

 

I built a jig for mine and I straighten them in a lathe with an indicator.

Glad to help out anyone needing it.

 

First indicator would be a section of the disk darker than the rest. The rotor should be a shiny, silvery, uniform color but when they warp, the part that exerts the most friction against the brake pad changes to a darker color from the heat. This darker portion can be inside or outside the disk. see here:









The wheel will not spin freely if the rotor is bent or warped, so you have to raise the front wheel, remove the calipers, then check it. If you don't have a jack, put 2X4's under the frame, then dig a little under the front wheel.
For a little more information go here:

https://www.hdforums.com/forum/touri...nt-brakes.html


Regards,

 

From the pic that TooEasy posted, I wonder if it is a problem with the rotors that have the single floating attaching pin. I used to straighten and put a crown in I-beams using nothing but a rosebud torch. It seems to me that with the single floating attach point on the rotor is where all the heat expansion will have to go. Thus causing it to warp.

 

You should be able to tell which rotor is warped just by jacking the front wheel of the bike up and removing one caliper at a time to see if the other brake is the problem one by turning the wheel and watching for the rub caused by the bad rotor.
I have found that replacing the bad rotor is the only cure for this problem. Even on a car, they tend to warp easier afterward if you try to cut them to eliminate the problem.