Yerf Dog ATV 150CC GY6 Engine

GUARANTEED FIT FOR Coolster Reaction 150CC ATV: New GY6 150cc Internal Reverse ATV Engine. Yerf Dog went out of business over a decade ago.  This is NOT the exact engine that originally came in your Yerf Dog but in an ugraded version of the same engine with the same mounting points.  With this engine you shift from forward to reverse using the shifter handle as oppose to a switch on the handlebars. You can get this same engine with more power as a 175cc engine.  175cc Racing Engine Upgrade  MORE CC MEANS MORE POWER Read our article on how displacement relates to more power.How big bore kits & strokers work To see more on converting this new engine to a 175cc racing engine please see: 175CC racing Engine Engine is shipped DRY with no oil. Be sure to add 750ml of 10w40 to the crankcase and 120ml of 80w90 to the gearcase before starting. IMPORTANT NOTES No returns on engines.Please do not return your engine. In the very rare event that there is a warranty issue please see warrant