Piaggio Typhoon 2 Stroke Bogging

So ive recently started my Piaggio Typhoon 70 and it starts and accelerated absolutely fine. However when i got to about 15 mph the bike has small sharp bogs. Almost like i keep revving and letting go of the throttle. I have never experienced this type of bogging on a bike before its like im repeatedly twising the throttle and revving when in reality im holding it fully pinned.
I have tried a new spark plug, the bike felt more powerful but the problem remains. I was thinking about getting the carb cleaned. Anyone know what it could be?
Thanks

 

Sounds like lack of fuel...
Have you Done some modifications to the engine?
If not, I should clean the carb.

If yes, What modifications?

 

I got the carb cleaned out now and the problem remains. Ive been told the mods the bike has are:
Malossi crank
Malossi 70cc kit
Malossi gear up kit
Malossi tc controller
Leo vince zx exhaust

Also i lost the fuel cap for the fuel tank so ive been using a plastic bag to cover the tank, this couldnt be the problem could it?

Thanks

 

Yes your causing an air lock in the system .

fuel caps have a breather hole as fuel is drawn out and needs to be replaced, the small vent hole built into fuel caps allows air to be drawn into the tank but if its tipped upside down keeps fuel in they are like a one way valve. without that your drawing fuel and and creating a vaccum in the tank. over a certain time your tank is not able to deliver fuel because there is no air that can replace and a vaccum is formed, if you remove the bag it runs ok untill the vaccum is created again and then that stuttering bog come back.

The fix ........ buy a new/second hand fuel cap and your problem should vannish

 

Thank you for the reply i will definitely try this and if it is the fix it will save me alot of money