Try and see if the leak is not from the timing chain tensioner, that is the easy one to repair an oil leak. If it is from the base of the barrel, the everything above that will have to come off to replace the gasket. Going that route, you will need as a minimum a new head gasket, the rest you can make yourself, not a difficult task, couple of hours and you will be done. Things to look out for is not to damage the rings when the barrel goes back or mess the timing. Don't use silicone sealer, it has the nasty habit of blocking oil ports. Try and get a low range torque wrench, the head bolts don't need that much torque. Good luck, this is not a difficult task, also, try Mr Google, might not have the same bike, but the concept stay the same.