Copyright WWW.DBBP.COM | updated 18-December-2021


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.

To be continued....