Wednesday, 11 January 2012

Royal Enfield Meteor Minor 500 twin

Here's the new project: it belonged to my old friend John Robinson, technical editor of Performance Bikes. I plan to restore it along the lines John would have chosen: better suspension, brakes and ground clearance, more comfortable riding position.
Early days, but it should turn out to be a handsome beast. Styling, if I can afford it, will resemble a Series 2 US export Interceptor – small tank, chrome and upswept pipes.

Monday, 9 January 2012

BSA A50/A65 wiring diagram

I've cleaned up the old wiring diagram which I first drew in 2009, and which has since been downloaded 44 times by people in India, Australia, Canada, the US and elsewhere. This new version is easier to follow. It shows a bike with a non-standard ignition switch, Boyer Bransden electronic ignition and a 12V conversion with Zener diode. Not how I'd do it now, but it worked OK.

There's a good quality hi res version free to download here:

What goes wrong with NX650's Keihin carb?

1000 miles later nothing has broken, fallen off or worn out. Considering how worried I was when I first saw the inside of the engine, that's a decent result. The one nuisance is a tendency to stall approaching junctions, even though the bike ticks over and pulls away perfectly well.
Another owner, Simon Relph, says they all do that, and the best cure is a new carb from an XR600. I've also talked to the previous three owners and they all say the pre-rebuild bike stalled like that for years. The question is, why?
Assuming the ignition and valve clearances are fine, and taking Simon's observation that a new carb fixes it, I decided that the carb must still have some problem despite professional cleaning. Replacement isn't cheap, and the carb isn't worn, so it must be possible to put whatever is wrong right. Maybe the design makes some of the small bleed drillings incredibly prone to gumming up?
I stripped the carb down and spent a long time with carb cleaner and compressed air, trying to ensure the four pilot drillings were clear. These are the holes which the pilot adjustment screw covers or uncovers as you screw it in and out. I concentrated on these bits because when I tried to set the carb up originally after the rebuild this screw made virtually no difference.
Carb reassembled and fitted, fire it up – still no good.
I have found some extremely small drills. They may come in handy.