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Andyman · 03-09-2009, 11:54 PM

My brother had several motorcycles in the past. One was a Honda CX500 which had a V twin water cooled engine and shaft drive. He said it would get about 55 MPG on the highway. I don't know if that's accurate. That's better than his other motorcycles. I think most of them got about 40 MPG on the highway.

I can think of a few reasons why motorcycles often don't get great fuel economy.

- they usually don't have any vacuum advance in the distributor

- they often have low gears, so the highway RPM may be double that of a car

- they don't run well at low engine speeds

- the tires have high rolling resistance

- the coefficient of aerodynamic drag is high

- the engine may be larger than necessary

I have read about some bikes that could get over 100 MPG. They usually had an engine size of 125 cc or less.

03-09-2009, 11:54 PM	#49 (permalink)
Andyman amateur mech. engineer Join Date: May 2008 Location: New York City Posts: 112 Sporty Accord - '88 Honda Accord LX-i 90 day: 23.25 mpg (US) Dad's Camry - '01 Toyota Camry CE 90 day: 22.81 mpg (US) Artie's Camry - '98 Toyota Camry 90 day: 37.3 mpg (US) Thanks: 0 Thanked 17 Times in 4 Posts	Honda CX500 My brother had several motorcycles in the past. One was a Honda CX500 which had a V twin water cooled engine and shaft drive. He said it would get about 55 MPG on the highway. I don't know if that's accurate. That's better than his other motorcycles. I think most of them got about 40 MPG on the highway. I can think of a few reasons why motorcycles often don't get great fuel economy. - they usually don't have any vacuum advance in the distributor - they often have low gears, so the highway RPM may be double that of a car - they don't run well at low engine speeds - the tires have high rolling resistance - the coefficient of aerodynamic drag is high - the engine may be larger than necessary I have read about some bikes that could get over 100 MPG. They usually had an engine size of 125 cc or less.