It’s a very straightforward job. The front wheel is held on by a nut and long, flanged hex-head bolt that passes through a shaft running through the forks, the wheel and an odometer assembly inside the right fork. Here is the assembly with the left fork, shown from the front. The big bolt in the middle is the one you need to remove to get the wheel off. To the left, you can see one of the sunken hex-head bolts that hold the disc to the wheel itself.
1) Use a spanner/socket to get the wheel off, but have something to rest the front forks on while you’re working on the wheel. Here’s what it looks like with the wheel off. The Odometer assembly hangs free on its cable to the left, and on the right you can see the bolt that held the wheel on. The inverted bucket is for the forks to rest on if it tips forward on its stand.
WARNING: Do not operate the front brake while the wheel is detached. The piston will pop out of the calliper head.
2) The disc has three larger holes for the bolts that hold it on. Here’s the new one I got, face down. Take the old one off with a suitable socket. I tried to use an alan key at first, but the bolts were too stiff, and I was only going to end up stripping them. In the end I got a socket converter to use with hex-head screw-driver attachments.
3) Replace it with the new one, but make sure you put it on the right way up! You can see which way is front by the recesses for the heads to settle into.
4) Tighten the nuts and put the wheel back in place, pushing the bolt back through the left fork, out the other side of the wheel and through the shaft in the odometer assembly. You’ll need to twist the whole thing slightly forward of the right fork to get the odometer assembly to squeeze back into place.
5) This is the wheel as the odometer assembly is being slid back into place. Make sure the hook on the assembly engages into the slot designed to receive it, or something nasty will probably happen when you try to drive it. Once engaged in place, slide the bolt the rest of the way through and put the larger nut back on the end (don’t forget your tax disc holder, if you have one mounted here!).
All done! Easy as pie…