Im new to the cbr world, but not new to motorcycles and my cbr has the most random fuel milage ever. When I got it I averaged 140 miles to a tank and recently I have only been getting around 60 miles out of 3 gallons. Any tips on what could be causing this? I figure I will start with the basics of plugs and air filter. But could it be something that needs to be tuned? Thanks in advance guys.