So my f3 has never run properly since i got it, it will start and run fine for a while but then with no warning will start to run realy lumpy and my m8 said it starts smelling of fuel when hes following it. Ive had carbs apart and cleaned and replaced coils and plugs but it still does it. Im thinking it could be electrical but unsure what to check, any ideas?

 

Sounds like it's running rich. Possibly a clogged/ restricted air filter or the P.O. could have rejetted it. Are you SURE it has stock jets? I believe stock is 135 138 138 135 mains, 40 slows.

Also check to make sure your choke cable is routed correctly and relaxing fully when disengaged.

Edit: if you're riding at altitude it could also cause an enrichened mixture.