Couple of questions

Is the exhaust just putting out a little smoke or is it fuming? A little bit at first is probably not anything to worry about.

Break in is sort of an extended process. Ride it light for about 10 miles or so then start riding like you normally would. I used a 20:1 mix with fossil oil for the first two gallons, 25:1 with the same oil for the 2nd 2 gallons and then 30:1 with good synthetic oil from there. The fossil oil allows the rings to wear in properly.

I personally think that anything over 25 mph on a motorized bike is a sure indicator of suicidal tendencies! These things simply aren't safe at much over that!

Have fun!

even if they say upto 45mph they mean 45kph which is like 32mph with lots of screaming.
but you can go faster with a smaller sprocket(cheap) or a jackshaft kit($$$).

i usually ride mine around 20-25mph.

want to save on gas,dont rev up your engine to show off at stop signs.
pull in clutch when going down hills.
heres a link for smaller sprockets and other good stuff:
ENGINE_KIT_PARTS_PAGE_2

The only way I can think of to save more on gas than you already are with a Motorized bike would be to take off the engine altogether and pedal!

i dont need to save on gas im getting 200mpg but even if youre getting less its still cheap to operate one of these bike engines. gas is $2.49 a gallon for me. i think thats like 1-2cents per mile for me. instead of saving money on gas its better to check to see if you have gas in your tank so you dont run out.since i dont gas up very much sometimes i forget to check.my muffler still has origional paint,no peeling or nothing and it never smoked even when i was at 16:1. using a 26" bike with a 44t sprocket i am able to go up to 32mph which is plenty fast for me since i usually like to cruise around 20-25mph. i have gone 200miles and used 4 liters of gas and still have lots of oil in the first bottle i bought. i am now using 20:1.