hi guys just a little help its been asked a thousand times i am sure but i have just brought a nsr 250r mc18 mK2 and want to change the gear box oil can you tell me which is the best oil for the bike please as i dont want to mess things up also would it be ok and safe to put some iridium plugs in there too or does anyone have a idea which i should put in for best performance it is deristricted and running about 60 maybe a little bhp regards to all a13bee.

Castrol Universal 75w-90 semi-synthetic gear oil (formerly Castrol Syntrax universal)