OK..I have 83mm bore b18c1 motor..I need to know which gasket is good to use?

Jeff-

 

I heard Cometic gaskets are really good

 

 

http://www.nipponpower.com/engine/gasket/cometic.html

stock gasket width is .030

choose accordingly

higher # will mean you will get a thicker gasket, so you will lower compression
lower # will mean you will get a thinner gasket, so you will raise compression

choose the appropriate bore.