When sealing the crankcase back up is it ok to run a thin bead of silicone round the flat, thin harder gasket? Or do you have to buy a special rubbery one?
If you mean the centre cases there is no gasket that goes in there,you should use propper case sealant as above,you will get loads more than one engine outta one tube and it's good for all sorts of jobs ,don't skip this sealer or you'll regret it