many years ago older engines were open to all types of mods,changes and alterations to make them perform better.. Modern technology allows for very little advance over what some very smart people have produced. By all means not let us stifle innovation but let us see that the modern product is pretty damn good when purchased. Production line methods dictate that not all products off the line are bad most are great...We do not spend a lot of money to buy our engines and should I think be thankful that we can motor along on a bicycle without peddaling very much. New members should take advise and temper it with a bit of common dog..The help that I have gotten from the Forum is exceptional. If starting out do not try to have the best damn thing since sliced bread ,give it a go off the shelf as it were if you like it embrace it,if not no expensive harm done..The cheapest,most fun filled,challenge,hobby of ego stroking,thing that one can do given the expensive world we live in.. GO Motorized Bikes,Be Happy and Be Safe..