Well.. Here is some info for you on Fuel...
The GT motors use gravity feed carbs with floats. Since the GT "good times" or HT "Happy Time" motors "I prefer GT ", Since these GT motors have gravity feed carbs with floats , they must be run in a more upright and level position. Since the GT motors are port piston valving type with small intake and exhaust ports, they are very efficient getting an average of 110 to 120 mpg city using a bicycle with a 200lb rider. This is typical. Using the New EPA Approved Black Cat exhaust mix 40:1 coupled with the new improved more precise GT engine and AMS oil synthetic, they burn super clean and last longer and are more reliable. Exhaust BLack Cat exhaust system does get hotter but is still away from user and should pose no problems. The "Black Cat" is engineered in such a way that the Cat is buffered center with volumetric Free Air Resonace Buffer around it thus lowering the surface temp of the Black Cat Perimeter to remain cooler. But..But.. This outer shell or Perimeter will still be much much hotter than the normal non Cat Chrome mufflers. Do not touch it ! It is hot for sure !! The Benefit of the Black Cat is two fold, 1 it meets EPA Approval by burning all unspent fuel, and 2 it makes the motor more quiet. Since the Black Cat has a large Valence, performance is not compromised. The New Black Cats are coming on line. Long Term testing is under way and so far engineering looks good and the Black Cat looks good too. IT just gets better and better.
Ok.. Now then.. As for some of the Weed eater type motors, some of them, not all, use a Diaphragm type Carburetor. These carbs are on a closed loop system and can be held in any position and the motor continues to run. It does not help efficiency or emissions properties. It is simply a function of positional run.
To sum things up, The engines, both GT and 4 strokers are getting better and better. Efficiency is super , reliability is great for all of our little motors and this is a good thing since talk about 12 dollar a gallon gas is real and Global warming is then the follow up subject. Help !!! IF gas goes to 12 dollars a gallon, 150 miles to a gallon of gas bicycle will cost the same as filling up a Ford Excursion now !!! Yes.. I know..It costs more than 3usd to fill an Excursion. But just because we have a bike that can go over 100 miles to the gallon , we still need Help !!!
