question on LH crank seal

[imsimon]

Hi guys,
MY bike is running really bad, wont rev past half revs etc, I know could be a number of things but im just going to start and work my way through things, I know it can be Cranks seals so have ordered them and going to start there. My question is do you use any gasket sealant on them like yamabond etc? on the web ive seen some people do and others put them in dry but couldn't find anyone thoughts of a gas gas owner?

many thanks
si