The decompressor holds an exhaust valve open until rpm is high enough to disengage it, at which time you get compression back once she's started. Its only purpose is to remove compression by holding the exhaust valve open so the starter can crank over the engine with ease. Do not remove it, it has to be there. All 4 stroke machines have to have it. Even kick-start machines have to have a decompressor or your foot would pay the price.

 

c i knew some1 would be able to explain it much better than me

 

ok, thanks im not sure how it works but i guess i dont have to know everything