Hi Kevin!
first of all i see your a new member, welcome to the forum and please PLEASE go and post an intro, chances are the other members wont reply until you do, doesnt have to be anything special, just a little bit about who you are, where your from, what youve got and what you want to do with it, takes 5 minutes and it will get you in the loop with us regulars.
congrats on buying a pre-div, they are the fastest of the series no matter what anyone says, the notch at dead centre could well be the head bearings, its worth taking the top forks off and having a look just incase they have worn a "dead spot" into the race.
viscosity? 10w/40, be sure it is a MOTORCYCLE oil and not a walmart special offer oil, if it contains mobylene then leave it well alone, putting a general purpose car/lawnmower oil in it will cause the clutch to slip and cause you no end of headaches, the sump plug is on the very bottom just behind where the exhaust manifolds go under the engine, it can be a right bastard to get off and if your bike is fitted with a Motad Neta system you will have to take the exhaust off to get it out, be sure to fit new exhaust washers when you put the exhaust back on or it is sure to leak (you may get away with using exhaust sealent in the headers for the first couple of times, after that its definately worth putting new washers in)
MOT checks, definately check the rear tail lights, there are two dual filament lights just incase one blows you always have one left until you get home, if the cables are a bit coroded these can blow within 5 minutes of each other due to high resistance so check them both before the MOT, other than that check the rear suspension linkage moves freely as they are prone to ceising up
let me know how you get on, im madly in love with the pre-divs, especially when they piss all over another young sod on a suzuki SV650 at the traffic lights.
regards
Foamy