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Discussion Starter #1 (Edited)
Hi everyone,

During the course of doing some periodic maintenance, I found that the front rotor was just below minimum spec. So I ordered a new rotor (non genuine of course!) from www.metalgear.com.au, along with new pads (for front and rear).

Anyway, long story short, I replaced the rotor and pads, and took the bike to a gentle ride down the street. Straight away I knew something wasn't right. There was a lot of "inappropriate" feedback through the steering...like it wants to wobble about. It was not doing this before the rotor and pad replacement. I made sure I did everything as per the factory service manual, and as I hadn't done this job before, I made sure that I took my time doing it.

As I was riding slowly along trying to see or determine what was going on, I look down along the front forks, and could see them 'wobble' forwards and backwards. What the...?

I took my wife's Ninja 300 for a quick spin to compare, as her bike is still on the factory rotor (still in spec)...and it felt so much better - like it should be...very smooth.
Got on my bike again, and the wobbles are very present and very disconcerting.

I went to the Google university library to do some research, and found that it may be the steering bearings are shot (although the wobbles weren't there prior to my putting a spanner to my poor bike!), or, the front tyre needs replacing.

Has anyone else here had the same problem - if so, what is the solution, please.

Cheers!

PS: Yes, the tyre (Avon Road Runners) pressures were check out!
 

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Discussion Starter #2
Just to clarify some points:

1. There was no hint of wobble before I replaced the front brake rotor and pads.
2. Tyres: Avon Road Runners in OEM sizes.
3. Odometer: 37,000km (22,990miles)
4. Wobble can be felt doing 5km (ie: real slow) to around 40 km/h - as this was my first brake rotor replacement (and pads), I was taking it very easy/slow just in-case I stuffed something up when putting everything back together.
5. I have read/searched this forum for answers/clues, and people say to replace the tyre and/or steering bearings. Thing is, this wobble was not there prior to doing any work on the bike, so it kind of has me puzzled. I was fastidious in doing the work, and as I wrote before, I did everything by the FSM and I took my merry time in doing the work.
 

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Lift the front and spin the wheel.

Warped rotor coming in contact with the caliper? Forgot a wheel bushing? Put the brake pads in correctly, with the friction side towards the rotor on both sides? Did you apply any front brake to align the pads yet?

Possible to get a pic?
 

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Get the front wheel up in the air and spin it to see if the rotor is warped and dragging.

Did you clean and grease the sliding pins on the caliper?

Grab the wheel and twist it to see if you can determine if anything is loose or not assembled correctly.
 

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Discussion Starter #5
Thanks ekare and jkv45 for your suggestions...righto, so this is where it's at...
Today I put the bike up on the stand:
  • The pads have been installed correctly, friction material against the rotor, plus the pads being different in shape, are confirmed to be in the correct place - by confirming with my wife's ninja 300 which still has the original/factory pads installed.
  • Yes, I applied the front brake to align and get the new pads seated correctly.
  • I can spin the front wheel without undue effort. I can spin it using one finger on the edge of the petal disc.
  • I spun the front wheel as fast as I could and watched for warping/run-out...I did this many times and couldn't see anything untoward, but stopped doing cos my eyes started playing tricks on me...and I don't have a run-out gauge.
  • Yes, I did grease the slide pins in the caliper before re-assembly.
  • I tried twisting the front wheel assembly by grabbing the axle bolt-head/nut, nothing out of the ordinary noted there...all solid.
  • I removed the front wheel and re-installed the original OEM rotor to see if that changed anything...to prove if the new rotor was warped or not. The test ride showed that nothing changed...still getting the wobble at low speed...meaning, the replacement rotor was not warped.
  • Giving up for the day, I tidied up the garage (swept out etc) and pushed my bike back into its parking spot when I noted something odd through the steering. Knowing that the floor was clean and clear of debris, free from errant bits of stone/grit and other crap, I moved the steering left, centre, right, and back again. Light-bulb moment! There is a definite 'detent' when the steering is straight/dead-ahead. The culprit(s) is/are the steering head bearings. They're shot. Strange, but they were find before I started working on the bike...
So that's it. I need to replace the steering head bearings. I did take photos and video of the spinning front wheel etc, but they are a moot point now.
Thanks for the suggestions folks. Much appreciated. Truly. I thought I was going nuts!

Case closed.
Cheers🍻
 
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