Front end shake when braking KZ550

Can anyone tell me if it is safe to reduce the diameter of a drilled rotor? I got the ProLite MD4052LS and the diameter is slightly larger than the rotor i was replacing.

The stock rotor measures 10 7/8" and the EBC diameter is 11 9/16".

Im not sure if this is usually a problem when using a KZ750 caliper, but I am currently using a KZ550 caliper and due to the increased diameter, the bracket cannot be mounted.

The biggest question I have with this, is if the diameter is reduced, it may result in some open holes on the edge of the rotor because it is drilled, I dont know what sort of problem that can create, if any.

I suppose an alternative solution would be to get a different caliper.

Having 1/2 holes around the outside would probably cause it to catch on the pad at a really bad time,not that theres ever a good time for that to happen! :sick: :woohoo:
Does anybody have a stock 650 rotor they could measure to see if its any closer?

I just talked to EBC and walked thru specs, Turns out the rotor I am using is off a KZ650C and is a different OEM part than I was searching for a replacement. Back to the waiting game...

I copied this from a post from Jeff Saunders (owner of Z1 enterprises)

Motorcycle Wobble Causes

There's a LONG list of potential area that can cause this.

These are not in any particular order

Wheel bearings

Steering bearings - repack grease, check tightness

Swing arm bushings/sleeves/bearings - replace if worn, repack grease

Fork springs aging - check spring length

Unequal fork oil - if seals leak, then your damping can be ineffective

Rear shocks aging, damper leaks - if you have oil leaking from the seals, the damping is toast.

Worn Tires/Mismatched tires/tire pressures/wrong size tires.

Wheel alignment - don't trust the chain adjusters - I visually align the wheels.

Bent rims/broken spokes - get the wheels off the ground and spin them - check for runout / damage

Front disc warped - check for runout

Steering & swing arm bearings are very common problems, but so are tire issues (pressure/mismatch) and wheel alignment.

Not having a front fender, as it helps stiffen up the forks. I’d suggest a fork brace.

Good news, my front end shake is solved!
I finally got the right rotor (well kind of), an EBC MD4059LS, threw on some new pads and tested it out....great stopping power and smooth as could be, no wobble/shake. For my particular issue it was definitely the warped rotor. I wish I had not overlooked it so early on, but now my steering and front wheel bearings are fresh and the brake operates like new.

Having a drilled rotor was never a priority but I do like the way it looks. For whatever reason the carrier on the ProLite rotor was half as thin as the original one, so I had to make a spacer to fill in the gap. EBC said this is the 'only' rotor with the specs I needed so it was weird that is was so thin. Oh well.

Thank you to everyone who offered input on this thread. It is all very much appreciated, at times I was at wits ends and it gave me new ideas to investigate. This is a hell off a community to have as a resource.

And loudhvx- I will be at 5 Star Bar come Sept/Oct for Japan and Custom night. Thanks for the suggestion, looks like a great time!

glad to hear you got it fixed. Hopefully will see you there.