Crankshaft machined

A while ago while out in our local curry house, I bumped into an old friend.  He owns a successful engineering company, and I was quick to ask him if motorcycle engines were something he ever had the pleasure of handling.  His answer was simple - "NO - too much hassle" (and to be fair to him, if your business is tier 1 engineering supplier to the auto manufacturing trade, nobbing about with private one-off jobs probably is more hassle than its worth) - "But, if you want to drop it round, I'll have a look at it for you.... as a friend".  And so I did.

It turns out that the sheered pin in the crankshaft was hardened, and so the only way out was to spark erode it out.  The Manurhin workshop manual calls this little pin "a magnetic cotter pin" - im not sure why 'magnetic' but my engineer friend and I decided that a new pin made from a piece of silver-steel would be tough enough to do the alignment job and yet sacrificial should anything fail (I'm relying on the tapered shaft to do all the securing of the flywheel)

Note only one hole was spark-eroded.  It looks oval at the top, but its a good true 2mm dia hole deeper down

Normally when updating this blog I would put a link in to the supplier or source of information, but in this instance, I'm not sure if Richard of RPS engineering in Birmingham would be overly grateful to receive a little queue of scooter tinkerers asking for fiddly-piddly machining jobs.  Its not really what his CNC machines are cut out for.