Poor Mileage FAQ
by Kristian #562
Please read the Disclaimer before attempting any work in this FAQ.

This FAQ is ONLY about getting poor gas mileage. If you have a problem with starting or poor running, see the Hard Starting Poor Running FAQ.

Why is my mileage decreasing?

Q. My bike’s mileage seems to be decreasing. What is going wrong.?
A. It depends on a lot of things.

The FAQs below might be able to help you out, they are in no particular order, but try the simple things first.

Easy to Check:

Medium to Check:

More involved to Check:

Feedback on Reasons for Low Mileage:

Excluding tire pressure and weight, can anyone give me their top 5 reasons why one might get low miles per gallon?

What Mileage should I be getting?

Q. So, what sort of mileage should I be getting.?
A. This is a very difficult question to answer, because it depends on so many things which you as a rider control. These cannot be considered as “repairable” contributing factors to poor mileage. These are riding conditions, on/off road, around town, preferred rpm range, altitude, riding style, laden/unladen weight, choke use, modifications.
Some inmates get 45-50, some 50-55, some 55-60. If you get less than 45-50 with a stock bike, normal around town riding on the road, and you have a high mileage bike, it’s probably time to check the Carbs. Same goes if you get less than about 50-55 on the open road.


Classic” Funduro and F650ST.

Richard#230 has a Staintune but no other modifications, gets around 55-60 mpg, but he is an older gentleman, who drives in the lower rpm range and I believe very steadily, by all accounts. Flash#412 on the other hand, gets low 40’s when he’s really going for it or fully laden and up to mid 50’s when he’s cruising.

If you want to see what sort of mileage some people are getting after a new exhaust/rejetting, see the F650 Exhaust Rejet Spreadsheet.

GS and GS Dakar

See the Fuel Tank FAQ GS

What is the Range of the F650?

See above for Mileage, but in General:



See the Fuel Tank FAQ GS

What About Ethanol in the Gas?

Q. I see in my latest Motorcycle Consumer News that all of the major oil companies in California, except Chevron Texaco, will be removing our beloved MBTE from the gas in California next year and replacing it with ethanol, to produce a new and improved smog gas. Does anyone know what this is going to mean to our motorcycle engines? Are they going to run better or worse? Are rubber parts going to dissolve faster? Inquiring minds want to know what will be in store for us next year, besides higher prices and fuel shortages. Richard #230, Pacifica, CA