The Rotax 125 Senior Max engine features a unique adjustable Power Valve. This ingenious system relied on exhaust back-pressure to create two port timings to deliver maximum power at low speed and top speed; so you get the best of both worlds. Like the Junior engine, the Senior Max requires no additional blueprinting or engine tuning prior to use. The standard setup of the carburettor covers nearly all operating conditions. For extreme conditions the jetting of the carburettor can be changed in between sessions, and no longer requires the driver to 'tune' whilst racing. The engine has an integrated electric starter with a Touch-And-Go (TAG) ignition. It can be downgraded to the Junior version with just a few components (available as a kit). A 6 month manufacturers warranty is included with the engine.