Hi I have a 550 maxim basically the same engine. Beneath the brake pedal on the the engine crankcase there is a little window in which you can see the oile level there are markings to indicate low level and max level. I found that it is best to put the bike on centre stand and run the engine for a couple of minutes stop let it settle for couple of minutes and get the best reading. I have the original owners manual and the oil capacity including the filter is 2.5 litres. I use Halfords motorcylce oil its about £9 for 2.5 litres. all the best brian