i have built two motor bikes with no issues at all.my last build(80cc ht) however starts fine and revs up fine,but has no power at all once you engage the clutch.barely has enough power to propel its self. i am using the same gas mixture as in the other motorbikes(wich run fine) already tried swapping sparkplugs with one that runs fine,nothing seams to help.any ideas? possible carb gasket issue? i did notice one of the head bolts were lose and torqued it down,could one bolt being loose have blown the head gasket? any ideas or help would be apriciated.thank you.