Hi my bike starts well runs fine ticks over runs well at quarter throttle but when opened up to half throttle it misses and will cut bike out if you open it up too fast. I have cleaned carb twice adjusted needle up and down adjusted the screw still it will only run with have choke half on. With choke half on it runs fine and picks up well. Any Ideas of problem I was thinking maybe wrong main jet or throttle slide it is obviously getting too much air or not enough fuel.
I gave some guidelines/information on the "Mysterious parts" and "Running a 16H/B4" pages of the website.
There should be enough info within the "normal"running requirements to help you solve the problem.
It indeed suggestes to much air/ to little amount of petrol at higher throttle setting.
First check if all parts are as proposed, and work from there on as given in the AMAL text.
Its a job requiring patience but if the carb is fairly OK it should work.