but when i hold my bike off the ground and lightly drop just the front end my bars,forks and front wheel vibrate like crazy my headset is tight everything is tight but i cant stop it.....wtf am i supposed to do?
You must have some pretty cruddy bike shops if they can't figure out the problem.
So the question is, has it always been this way or is this a problem that developed over time or when you upgraded or replaced parts?
You need to check everything.
I did some reading... it is amazing what you can find.
Reading up on the FSA Impact it says that it is only compatible with Campy integrated headsets and I am going to take a wild guess that your BMX is not Campy spec'd. There may very well be issues with the crown and headset races fitting properly.
With that being said that headset may be shifting around in the head tube ever so slightly and no amount of adjustment is going to make it work.
With integrated headsets being rather new there is no set standard and compatibility between them can cause issues.
Contact the maker of your bike and find out what headset is supposed to go in there... a green mechanic might have built up the bike and may have not been aware of these compatibility issues.
Your bike shops may look at your bike and not realize this either.
Although I am a mechanic (and a good one) I don't spend too much time with BMX bikes so have to do some reading up on specs... the specs on the bike say it uses an integrated headset but does not specify a specific type.
If everything is set to where it supposed to be and things still aren't working my suspicion is that there is some compatibility issue especially with the FSA being a Campy only part.
Again... let me know if the new headset solves the problem and I'd advise contacting the manufacturer to see what and what isn't compatible to save yourself time and money.
If you bring questions like this to the mechanics forum you will get a lot more attention and replies from folks who probably are intimate with issues like this.
Originally Posted by http://fitbikeco.com/PDF/09_spec_charts.pdf
all fit frames are designed for 1 1/8” integrated style headsets (campagnolo compatible 45°/45° with 41.8mm o.d. Cups), press fit mid bottom brackets,
14mm rear axles, and 25.4mm seatposts. All dimensions and geometry are based around a fit frame using a fit fork.