The headlight shell on this bike had a big hole in it, in which
I had put a voltmeter. Pretty useless as I could not see it there,
so I decided to move the voltmeter to the top motor mount and
fill the hole in the headlight. I guess the advantage of the acid
and oil finish is that you can blend in repairs quite easily.
All has to be bare metal though, it won't work on filler...
I noticed that 2 bolts of the sprotor ( a combination of
sprocket and brake rotor) had broken and the holes in the sprotor
had developed a lot of slop. This was probably caused by the
offset spacer between hub and sprotor. The sprotor had been
mounted with 5 long bolts and that is all wrong ofcourse. I
designed a new spacer which uses 10 short bolts and had that
CNC machined from steel.
The holes in the sprotor were worn oval so I drilled them
oversize and fitted a steel ring in each hole to get the proper
diameter again. I also recessed the heads of the bolts, after
machining each bolt head for a tight fit in the recess. Everything
is tight now with zero slop, much better!
I designed a new steel one-piece top motormount
with a mounting point for ignition switch and voltmeter and had
that lasercut from 6 mm steel. It turned out that 6 mm was too
thick for the ignition switch so I had to machine a recess, but
how to clamp this part in the milling machine?
I machined a piece of roundbar and welded that
to the motormount so that I had something to hold it with and
then succeeded in machining the pocket on the bottom of the
motormount. I welded the extra bit of metal on the front of
the motormount to the bottom to create extra thickness for the
threads of the coil mount.