Hi Thanks for coming back, answers below.
What do you call bogging- The engine die's as after you begin to apply the revs on throttle. So can't get it to rev out.
What carb- Standard Orginal
Air filter state/condition- Air Filter is brand new
What jetting- Not sure
Is float valve passing- May need help, not sure what this means
Is it different behaviour hot to cold- Can't get it hot
Has it run well before- Yes, I rebuilt it, though I didn't touch the carb or engine much, just a good service. Ran like a dream last time out!!
Are there any changes to inlet tract or exhaust system from standard- Exhaust is completely standard with a new end pipe but that was there when it ran well.
Whatever other clues you can give
It does seems to be spitting out a thin black substance, from the end of the pipe, but I assume this is just unburnt/poorly burnt fuelmix.
It also does not like the choke at all to start it?
Any help appreciated, it's been about 15 years since I messed with bikes so a little stumped, given it ran like a dream a few weeks ago and nothings change. I have started it and just run round the garden a few times, could I have coked it up, but I did add a new plug with no difference?