Motorcycle Repair: poor gas milage, air fuel mixture, mapping problems

Question
i have had my 1999 suzuki 1500 lc tuned up and serviced for the year and i am loosing approx. 6 miles to the gallon on fuel consumption.

i have taken the bike to the repair shop twice and they can not explain the loss of milage.

what causes that is it the plugs or the carbs.

Answer
Hi Mark,

Some causes for excessive fuel consumption are rich air-fuel mixture (jetting), worn needle jet, worn or incorrect spark plugs & gaps, dirty air filter, restricted air intake, carbs not synchronized, and ignition mapping problems.

Respectfully,
Mark Shively