Good of you to drop by with some sensible questions!
I did actually give your method some thought but the pump body that I was working with was badly scored around the periphery so a new gear of the the same OD would not really restore the pump.
I am told that the culprit for damage to these pumps is broken clutch wires that happily pass through the gauze screen.
I tried lots of options for gears, including designing one myself. The quotes I got were astronomic for those companies who bothered to answer.
In the end I found HPC hears which supplies a range of stock gears. I found that their 14 DP, 10 tooth gear was, strangely, about 1.5mm bigger diameter than the Honda gear despite having the same diametral pitch. The HPC gear comes as a wide blank from which you can cut a pair of gears (importantly with identical outside diameter).
big gear by graham.curtis, on Flickrhttp://www.hpcgears.com/pdf_c33/23.126-23.131.pdf
The bad news and good news is that these gears have a 10mm bore compared with the Honda gears, allowing a little tweaking of the shaft diameters and the centre spacing. The gears cost about $20 each (makes 2 gears).
I pondered making my own "D" bits to do the machining but my little boring head worked just fine. I couldn't find a suitable end mill from stock and don't have (yet) a tool grinder. What you see in the pictures above is what I end up with. 6mm wide gears are easy and the cover plate could be machined like the Capellini versions for even more capacity.
The scary thing is that these pumps are 'designed' to operate at 10,000 rpm.
Incidentally, while doing this I realized that a poor man's fix would be to flip the gears over so that the scores in the casing did not match up with the scores in the gears. New gears are available still but the ones I got from CMS in Holland were rusty. I did buy some Cappelini gears before I realised that the casing was badly scored in several of my pumps.
G
