k2 Burgman 400 air/fuel screw location and turns out?? anybody have any idea please...

Make sure there are no air leaks at the joints.

I guess you mean the joints of the exhaust? its one pipe from the cylinder head/port which joins the muffle via a clamp type fitting. So it could be sucking in air via the muffler joint causing the issue??

Any air getting in at a joint will allow any unburnt fuel to burn
thats often when you get the popping.

Hi stubo, if it’s any help I agree with Ralph, most usually air ingress. On the original can there’s a thin gasket at the join with the down pipe that has to be in good working order. On The Burgman they seem to perish after a few years. In order to remove the rear wheel you have to break that join to remove silencer. I’ll usually replace the gasket then. They’re relatively inexpensive. It may be you need a gasket specific to your new can? Best of luck anyway.

Thanks very much for the help guys much appreciated

one other question for you all...
When I open the throttle up to accelerate from and standing start it very briefly stutters before the revs go up and the clutch engages and the bike accelerates? is this a normal thing on the early carb models(k2)
cheers.

Not normal but it could be due to the non standard exhaust did it do it before the new exhaust was fitted

it came fitted with this exhaust unfortunately but im trying to acquire a standard exhaust which isn't easy

There's a copper ring gasket on the head end of the standard burg exhaust. If they reused the old one when they swapped the silencer, that could be missing/leaking.