@GarryM welcome here!
In this case I would start with basics, like..
METIN box out...
At carburator model.
-check sparkplug, cap and cable to coil
-check fuel support, fuel filter, lines
-airfilter out
-vacuum hoses all plugged
-see if it helps when you open your fuel cap
-side stand switch if mounted
-starter switch, kill switch
-this two thin cables to ignition coil
-front panel off, check all relais
-is all electric working properly, lights, brakelights, indicators?
At injection model the same plus checking connectors/cable to CO -sensor.
Pls see all this and come back to ask.