Christo... Based on your initial query, I would guess you are not that comfortable with mechanics at this point but willing to give things a shot. I think before disecting your bike's engine to fix an oil leak you FIRST confirm where the oil is coming from. You MAY THINK it is the head gasket but it can also be coming from a variety of other locations... oil tends to work its way away from where it actually leaks from and makes diagnosis confusing. So.... Clean the engine. Get some powder deodorant spray and spray the gasket line, the cam end plugs, the tach drive, the OUTER stud nuts and anyplace else where there is any potential for oil to leak. Start the bike and let it run for a minute or two and then shut it off. Look for the powder to be dampened by the oil. NOW YOU HAVE FOUND THE OIL LEAK. It may be in the valve cover or cam end plugs or oil may be leaking from the stud nuts or elsewhere that are EASY to fix.
If you find that the problem is that the head gasket is leaking, your biggest issue will be the cam shafts. You first remove the valve cover. Take off hoses and reed valve covers. Then you will be able to lift the valve cover clear of the cam chain tower while removing the valve cover by sliding it a bit to the rear and then out the side. The you will remove your cam chain tensioner. Once the valve cover is off, you will first remove the bolts holding the cam caps which are used to retain the camshafts. Once they are loose, the cam chain will loosen. Take off the upper cam chain idler assembly which is held by four bolts. This is your best opportunity to drop something to the bottom of the engine. If you do, it can generally be retrieved by removing your oil pan and fishing it out. In any case, take care because once the bolts are removed, there are a steel plate and rubber pad under the bolts that are loose and can drop in the engine. It isn't very difficult to keep track of these parts if you are aware they are loose. Once you remove the idler assembly, you pull the cam shafts out. The cam chain needs to be tied up to an engine stud or the frame so it doesn't drop down into the engine. It can be a chore to fish out with a coat hanger. Then you just loosen and remove the nuts on the engine studs and two bolts on the end of the head. At that point, you can pry the head a bit up at its pry points as shown in a Factory Service Manual (FSM) and then lift the cylinder head off while holding onto the cam chain. Once the head is off, tie the cam chain again. Then clean the gasket surfaces of both the head and block. Put a new gasket in place. I would highly recommend using NAPA Gasket Sealer. It is spray on stuff in a blue can and comes out red so you can see it. Follow the directions and spray the mating surfaces as well as both sides of your gasket material. When the stuff starts to tack up, put your cylinder head back on (hold that cam chain so it doesn't drop in the engine). At some point, re-anneal the copper washers that go under the stud nuts. This means heat them till they are red hot and drop them in water. This restores their ability to seal oil. Use a propane torch. Torque the head according to the pattern and to the specs given in your FSM. You will torque each fastener twice with the second pass tighter than the first. Again, refer to your shop manual for reinstalling the cam shafts so that cam timing is maintained properly. Failure to do so will result in bent valves. Reinstall your cam caps in the order described in your FSM. Once installed use the PROPER torque wrench and torque the cam cap bolts to the exact spec given. I would clean these bolts with a wire wheel when they are out to ensure no problem reinstalling. These bolts tend to strip the thread when overtorqued and that is why the torque spec adherence is critical. Then you reinstall your idler assembly and loctite the four bolts holding it and at THAT POINT, check your valve clearances per your FSM and replace any shims where clearances are incorrect. Reinstall valve cover (using a new gasket there too!) and ride!
Think about what happens to the "Base Gasket" when you effectively remove the torque load from it by removing the head. This is just common sense to replace the "Base Gasket" as well. He's already removing the top end. We wouldn't want him to do this job over again (possibly immediately) because of a simple oversight. This is not even metioning all of the other little parts that should be inspected and possibly replaced. It also says in his signature line the bike has over 100,000km. 
