Hi my Gillera runner 125 4t starts and revs fine when cold but soon as it warms up it bogs out can keep it running but won’t rev up checked compression which is gd check timing valve clearance checked stator cleaned carb out checked the choke is working got spark everything seems good but I took of vacuum line to the fuel pump and put my thumb over the vacum line on and off and then I can rev it but then it runs out of petrol obviously because there no vacum for the fuel pump what could it be pls help

Scott, August 2022