XB9S MPG

[1972c10]

@ Captain chaos. just raise the limiter on the 12, I bumped the limiter up on my 9 and it still keeps building power up top

 

[captain chaos]

@ Captain chaos. just raise the limiter on the 12, I bumped the limiter up on my 9 and it still keeps building power up top

With a 3.813" stroke running more than 7000rpm with a 12 is just begging for internal engine parts to become external ones. Piston speeds get astronomical above 7k. Buell raised the rev limit to 7100, I believe, on the later ones but it required stronger internals to do that. Even still, the term "ragged edge" applies.
The 9's can get away with a few more rpm because of their MUCH shorter stroke (3.125") but then the pushrods and inherant valve float become big issues. Be careful with adjusting the rev limit, there is a VERY good reason why Buell set it where they did.

 

[Blaylock1988]

Internal combustion engines have their highest efficiency at about 90% throttle at very low RPM. If you want best fuel economy when riding around at low to moderate speeds, shift into 5th gear at around 30 MPH and crank the throttle to just a little under WOT. You won't have much power or torque but you will have insane fuel economy, nearly double your normal MPG...

Chevy had issues with it's corvettes not meeting fuel economy standards, so instead of redesigning the engine to be more fuel efficient, the car would temporarily lock out 3rd, and 4th gear, forcing the driver to shift straight into 5th to get better gas mileage numbers. You can imagine that a lot of people were upset about this and would modify the transmission so it wouldn't lock any gears out. But chevy had the right idea for getting better gas mileage.

The concept of "overdrive" is uses this idea. It gears the car WAY up so that it keeps RPM very very low with nearly full throttle to get better efficiency at higher speeds.

 

[nativeXb12Rbuell]

here is the other main buell mileage threads.

Buell mileage 1125R & 1125CR


Buell XB Mileage


Buell-tubers-mileage