You want a bike that can survive your off-road romps yet turn civil while riding through the city. What you need is a dual purpose motorcycle such as the ones under Kawasaki's KLX series. For a midrange bike in this category, the KLX 250 is just the right blend of city racer and motocross bike. This bike has a 249 cc, four-stroke, four-valve, liquid-cooled engine paired with a six-speed transmission. With its pair of 16-way compression suspensions and rebound damping adjustments, the Kawasaki KLX will easily survive the rough and tumble of those trails you frequent. You can find this dual purpose bike and all the parts needed to keep it going among the wide selection of motorcycles offered by reliable sellers on eBay. If you want a variant of the KLX 250S with more power and better grips, then you should choose the Supermoto-inspired 250SF. This bike is tough and fast enough to take on flat tracks, race tracks, and motocross trails.