Small Enya engine 049 with a broken crank shaft?

All I can suggest in this instance (unless Ken Enya suddenly discovers an overlooked cache of spare parts languishing in some dark corner) is to dismantle the engine, chuck the shaft on a lathe (I'd be using a collect not a conventional chuck in this instance and drill out the broken stub to take a smaller diameter threaded stud or allen hex head cap screw. It won't be pretty-and it won't look original....but it will give you an engine you can actually use again.

If you have access to really good equipment, you could insert a stepped insert-the narrower thread inside the shaft, and get the outer portion machined back to the original thread diameter and rethread. You'd need quite good steel and good machining gear to do this accurately. I had this done for me on a late model DC Dart* by Jon Fletcher in Australia-effectively rebuilding the broken shaft to 'back to original' dimensions. Of course the shaft was hardened and ground, and he had to use a carbide drill to do it....

*the very last run of DC Darts produced ca 1983-4 quickly gained notoriety as having shafts with about the same strength as a carrot...and snapped just as easily. Anecdotally the entire batch of shafts had their hardening and tempering badly messed up. Whether this was a cockup at DC , or the job was outsourced.....has never been made clear. This batch of Darts are readily identified by their yellow anodised cylinder heads, rather than the traditional red or pink. The general advice has always been"if you have one-don't run it..."

ChrisM
'ffkiwi'