Quote Originally Posted by moving2time View Post
BigJohn, Thank you for the reply. You answered the big question I had regarding the Zipper a Joe B
Joe B

On the 1622 BigBore (which is not yet available, Still being tested) does require the case to be split and the cylinder sleeve openings machined out to fit larger cylinders, As well as a change of the Cam, likewise the Heads have to be machined to fit the larger cylinders, This keeps thicker Cylinder Walls to handle the power increase. As far as an airbox is concerned in most cases it allows cooler air to the carbs, cooler air is richer and thus produces more power I believe the formula is for every 10 degrees of air temperature increase to the carbs you loose 1% Hp, engine heat can increase air temp to carbs by 40 degrees or more thus a decrease of 4+HP.