I have that same sort of problem when I ride 125's. Last time I rode Gomer's son's bike I was doing this one double and i would get everything right but my feet would automatically come off of the pegs and up near the airbox. This brought my front end down for the landing, I know that alof of people use this technique to jump but I don't mean to do it and it sort of scares me.
You're probably just too tense, this used to happen to me all the time until I got used to riding and jumping. Just hang loose and keep your knees bent on the face and then when you lauch slowly straighten out your legs to push your bike away from you, then loosen your legs again for the landing. It's hard to explain, and it sounds kinda hard, but once you get comfortable it is completely fluid.
I am not clear on when your feet leave the pegs. If they leave the pegs violently on the impact of the face, I suspect your suspension is way too soft. Have a experienced rider watch you or consult a suspension shop to make sure your suspension is in the ballpark.
Be real careful with jumps. Take it real slow. I have two less riding buddies because jumps ended both of thier riding careers.
Try gripping the bike with your legs to try and keep your feet on the pegs. I actually always do this when jumping. I bring my feet up a bit and can kind of whip it (not well, I ride an XR100R). I would suggest gripping harder.
My feet leave the pegs when I am at the apex of the jump. I think the problem was that I wasn't holding on tight enough with my knees so after the bike stopped going up I did'nt. I'll try it next time.
I have a hard time using only my knees. It feels better for me to use the inside of my boots to grip the frame along with my knees. If by chance you still are launched upward & off the pegs bring your legs in and catch the side number plates with your boots and it should help from summer-saulting over the bike.
Using knees is sometimes more of a figure of speech than anything. It's actually your thigh muscles that do the work when we squeeze our legs together. Unless you are short, like me, and rearward...your knees prolly don't even touch the bike (lol..sitters excluded). But racehorse jockeys do the same thing with their legs as we do to help control their ride, and you will never see a jockeys knees touch the horse. But squeezing with the knees is also what they call it.
WARNING! THIS IS A METHOD THAT MAY CAUSE DAMAGE TO YOUR BIKE
Sometimes when no matter WHAT I DO I STILL get tossed off... I will put my right foot UNDER the rear brake lever. Please don't flame me for this.... I only do it occasionally... and I realize that it might be hard on the lever... but it really does help on those jumps when it seems like nothing else does. Please realize the risk to your bike before trying this. :cool:
If you are comming off that much, I suggest a nice can-can...or maybe a lil heel clicker would be in order! Might as well get some crowd appreciation out of it while you are at it!
Remind me to do a "look-back" anytime I happen to jump before you, Moo! :)
I don't want to miss any good stuff!
If your body is getting pushed up in the air away from the bike off jumps, it may be that your legs are too stiff - rigid - locked as you launch off the jump. What happens is that the suspension compresses into the face of the jump and then rebounds as you are taking off. If your legs are too stiff (or worse - knees locked) when the bike "springs up" then that upward force is transferred directly from the pegs to your 2x4 legs and it launches you.
One thing you can do is to "suck it up" - a BMX and mountain bike technique in which you start the jump with straight legs and then as you launch, you bend your legs and let the bike rebound up to you. You'll see this a lot at the pro level, when they are trying to stay low off the jumps - they can then straighten their legs and push the bike down to the ground sooner and get back on the throttle quicker. Another technique you can try is to squat as the bike compresses into the jump face, and then do a little jump with your legs as the bike launches (picture a skier taking off one of those huge jumps - just before he takes off from the big ski jump, he compresses and jumps into the air). Do this on SMALL jumps first to get the feel for it first. The best general advice is to stay loose. Too tight and the bike will toss you around. Hope this helps.