check and clean your rave valves, do a compression test, check ht leads and if needed cut back a couple of cm's, on the carb rebuild did you replace the little internal fuel filters?, did you replace the hoses correctly, definately replace plugs-for the sake of £2 its a win win situation.
when you rebuilt carbs did you use the correct size spring for needle/seat, did you flush jets on carbs? did you adjust low speed and high speed screws? you may have an air leak somewhere causing to flood carbs with fuel causing the bogging-did you put correct base gaskets on carbs and were they installed correctly-as sometimes they will move slightly-same for the exhaust gaskets.
iff all that has been been done and checked and been done correctly-it must be elctrical related-or a possible leak in crankshaft gasket