Updated - Still running rich

[Greybeard]

 Can't help much with choke as I've never had or seen one, but imagine as GB suggests, if you hold the throttle wide open (engine off), you should be able to feel the choke open and close....should be open/up for riding I guess....

The choke is on the outside, (away from the engine) of the throttle slide isn't it?

[duTch]

 

The choke is on the outside, (away from the engine) of the throttle slide isn't it?

 I have in my head we're dealing with a monobloc (?), in which case the opening in the top of the throttle slide for the choke thingy is toward the atmosphere side of the slide.  Also corresponds with the cable abutments in the carby lid -  so I guess that's a yes-ish...

[RogerSB]

the choke thingy

Air valve  .

[RogerSB]

It's funny how these engines differ in needing the choke. Mine only needs choke if it's really cold weather. I have an air filter; I guess bikes without one may need more mixture enrichment to get going.

That was very observant GB. I do normal have an air filter fitted but that photo was taken to send to my insurance company and I remember I was working on my bike at the time so the filter had been removed for cleaning.