piaggio typhoon not runing properly

my piaggio typhoon jults and stutters when im driving it and sometimes even slows right down to about 20mph and its as if fuel isnt getting through so i cleaned the carb and changed the fuel tap but it still does it so i just wondered if anyone had any ideas what it could be thanks

 

help please need to get this sorted as i want to sell the bike thanks

 

I would check your spark, change your plug, check your wiring at your coil....and your spark cap....
Next, check and see if your carb intake clamp is not broken and is tight....Might be your reeds are loose or are bad....
Also, do a vacuum test, and see how your compression is...might have a compression leak...