Rough running cold - now not running

Forgive me if this takes us into egg sucking Grannyterritory...

Big air cooled bikes take a LONG time to heat through. Although bits of the bike will be too hot to touch almost immediately it can take ten miles or more before the engine has warmed through completely. Similarly it can then take lots of hours to cool down properly.

My Commando used to start reasonably easily. It would take one or two kicks to get it going even after it hadn't been used for a while. You say it had a Boyer fitted, which is good, and that you have recently timed it correctly. From past experience I would counsel you to check all the connections on the stator plate very carefully. One way to do this is to take the cover off the stator housing, switch on the ignition and gently poke around. What you are listening for are cracks as the spark plugs fire which indicates a poor connection. Gently rock the stator coils and move the wires about. A good result would be silence. Any cracks and you will need a repair/replacement.

Assuming that works OK check your spark plugs are correct, accurately gapped and fit for purpose. New ones aren't expensive and I'd be tempted to change them anyway. If all that is good and you can get a good spark when you kick the bike over with the spark plug out of the cylinder and touching a good earth then the electrickery should be good enough. I might suggest that you avoid being the earth for the spark plug ... it hurts!

I am going to assume that you are running the standard Amal carbs with a standard air box. Simple one first: you have got some fuel in the tank, haven't you? Of course you have. What sort of air filter have you got and is it reasonably clean? Are there any other sorts of obstructions to the air flow or leaks from the manifold area?

Do the carbs flood properly when you tickle them? Does the bike make any sound when you try to kick start it? i.e. is it trying to fire or just dead?

After this we get into all sorts of stuff: are the tappets adjusted correctly? Are the float heights in the carbs correct and equal on both sides? Has it got the correct jets in the carbs? Are the jets blocked?

See hours of black fingered fun! Good luck!

Hi Andy.

You say carb in the singular but perhaps this is a typing error?

If you know the carb/s are all clean and assembled correctlycould be an air leak somewhere on the manifold/s, but my hunch is that it is the Electronic Ignition.

My experience with electronic systems is that they can play up in all sorts of ways. One effectis for themto produce sparks with erratic timing, you can set them manually but the spark timing jumps all over the place when running. This can be checked with a strobe, but you should do this with a cold engine to replicate the fault temperaturecondition. Look out for missing flashes too.

Also as Ian Wooleysuggests, it could be thespark plugs playing up.

Les