Background
I was riding to work one morning on the zed when I applied the front brake only to hear a loud clunk sound and see something fly from the front. I stopped carefully and discovered one of the caliper mounts had broken. I quickly located the missing piece and then turned the bike around and put it back in the garage till I could checkover the rest of it to see the full extent of the damage and work out what had gone wrong.
I didn’t have a replacement fork leg at the time so I removed the caliper and converted the brakes to single caliper mode. A few months later I sourced a spare pair of fork legs in Sydney and asked a friend if he could collect them, strip them and send me the lowers. He got to keep the internals and the fork tubes in return.
The pictures below show the damage and the replacement parts cleaned up. They were sent to Specialized Blasting Services to be cleaned up, the result is below:
Broken Lower caliper mount. 
Replacements cleaned up 
Pre-oxidation stage. It took some time to locate a genuine original set of lowers.
Disassembly
The disassembly process is simple with the correct tools.
Remove the complete fork leg from the bike, don’t unscrew the top (you can loosen it slightly).
Remove the dust cover and under the cover there should be a snap ring that you need to remove as well.
Tip the fork leg upside down and using a rattle gun, push down hard to release the 8mm Set Screw, do this on a soft piece of timber to protect the top of the fork leg.
Take out the 8mm Set Screw and drain the oil via the hole, pump it a few times to push oil out.
Reef the tube and the lower apart. The seal should end up on the tube, discard it.
Drain the remainder of the oil and clean the parts. Refer to the service manual to work out how much oil you need and the correct weight.
Below is a set of forks from the z650.
Take off the dust seal 
Remove the snap ring 
Locate the 8mm Set Screw underneath 
Use an 8mm 1/2″ drive hew driver socket 
Push down using an air powered “Rattle” gun, to loosen the grip. 
Upright it and drain the oil 
Give the upper and lower a good tug in opposite directions to separate. 
Separate over the oil pan. 
Clean and layout the parts.
Fork Assembly
Soon after the parts arrived back I re-assembled them onto the front end.
When installing the new fork seal, use some plastic over the sharp fork leg edges to push the seal over and sit the seal on the tube, you may need some rubber grease to help it slide over.
Use a PVC pipe slightly larger in diameter of the fork tube and gently push the seal into place. Fit the tube into the lower in the reverse order of dis-assembly, the seal should push easily into the lower fork tub recess. Put the snap lock ring on and then re-install the 8mm set screw on the bottom. Fill oil into the fork leg after you have re-installed the leg back on the bike.
No sooner had I installed the new fork leg assembly I spotted the brake union in urgent need of cleanup as well.
For the last few years the z900 has been living the high life in the lounge room with the odd trip out. However I noticed the forks were starting to show some degree of corrosion and the brake parts where showing the classic oxidation from leaking brake fluid.
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