l wanna know how to come out the hole on a dirtbike and a banshee like this http://youtube.com/watch?v=Qw_t3JgmKRE&feature=related on the 24sec u see how he launch the bike.. l have a kx85

launching is different depending on the surface u r on & what kind of traction u have. with enough traction u can put the bike in 2nd rev the motor way up & dump the clutch keep u weight way forward to keep the front end down & get u r foot on the shifter as soon as possible. but if u have limited traction launching becomes kinda like art work there is a fell some time less throttle gives u better acceleration
l always practiced starting 4-5 times before each race & had someone time me & also time the other riders who would practice. if my times were the best l was goo but if not l would often let a little air out of my tires to give me better traction. hope that helps

It is just a matter of proper clutch and throttle control combined with correct body position. Get you body forward, chin over the handlebars, elbows up in the ''attack position''. As far as clutch and throttle that just depends on the bike/quad. Depending on the surface you may have to slip the clutch. On loose dirt you can pretty much just pin the throttle and drop the clutch. Start out easy and work your way up. Practice makes perfect.