4 stroke 125´s are no good for speed. They are good for fuel economy and reliability. if you want speed and fun, get a 125 2 stroke. The standard DT will do 65mph if its restricted. Get the whole exhaust changed to a DEP full system, and the powervalve tweaked for full power and expect 85mph. Always use fully synthetic 2 stroke engine oil and the engine will do 20,000 miles easy.