No cold start valves on this primitve beast!!!

I had the same problem with my daily driver and it turned out to be the little blue diaphram in the carb itself had a pin prick hole in it!!!

To the btm right of the carb there should be a square like chamber with 4 star shaped bolts holding it together!!! Take these out and replace the diaphram!!! Be careful because this can quite fiddly and dont loose the horseshoe clip inside!!!

Get the air/fuels done again and it should be good as new!!!

If this doesnt work change the dizzy cap and arm!!! Might help!

Good luck matey