Hi, i have a 93 banshee, everything works perfectly fine, i can rev it al the way up while on neutral up to 1st 2nd 3rd 4th and 5th gear, the problem starts at 6th, i can have it on low to mid low revs, when i try to rev up on 6th the quad bogs, i tested it on a straight line gave it full throttle on 6th it started to bog, it doesnt turn off but it fails, and it kinda wants to rev up but then it fails again and so on, bottom line is, 6th gear bog, what could it be? What can i do? HELP