Had the same with mine at about 25K , could be reduced pressure / manky fuel, I purged the injector pipes of fuel near the injectors and what came ot looked like home made cider, manky particle ridden fuel, it fired up straiht away and has ran since.
I too bought some iridium plugs that made little or no difference to the running , as long as your gaps are ok and you have a spark (yellow) it should run.
My next job was to strip the bike down to the tank so i cold remove the fuel filter but luckily never had to.
My god there's a lot to a silverwing , you need a empty garage to store all the parts as you strip the bike down. Honda certainly put this bike together well for the £1450 i paid for mine , you cant get a decent bicycle for this money let alone a monster scooter!
Now introduce yourself buddy