My 125 dragstar seems to have some plAstic fins on the top of the heads the first few fins appear to be plastic they appear to bolted to a metal bracket above them 

 

do they serve a purpose can I unbolt them from the bracket with out disturbing the head 

Have to ask the question, why are you thinking of taking them off? If it's just for the look  you want then ok but why did Yamaha add them to the bike in the first place would be my starting point.

If I remove the fins I gain over an inch in height ( trying to fit the draggy engine into another bike ) 

the parts I m talking about look like they are part of the cylinder head  but when you touch them they are plastic  an  have some movement in them they bolt on to a metal bracket 

they are found under the plastic covers that sit on top of the head 

Oh that makes more sense, thought you were just going for "the look" might be an idea to try it without them and see what happens if no one else has done this before then you can write up how it worked out on here.

Can't really remember much about the cosmetic parts of the 125 draggy, im sure it you take them off and there are no internal parts visible then just ditch them if how ever your faced with a hand full of oil and a valve picking you in the eye then id suggest keep them on