Start by confirming there is actually a problem
Before diagnosing anything, check that consumption has genuinely changed:
- Are you comparing dashboard figures or brim-to-brim calculations? Dashboard readouts are frequently optimistic and can drift
- Has the weather changed? Cold air, headwinds and winter fuel blends all cost fuel
- Has your riding changed? More motorway, more traffic, more luggage, a pillion
- Did you change tyres? A more aggressive pattern costs fuel
- Did you fit luggage or a screen? Aerodynamics matter more than most people expect above about 100 km/h
If nothing has changed and consumption has, work down the list.
Free to check
Tyre pressures. The most common cause and the easiest to fix. Underinflated tyres increase rolling resistance measurably. Check cold, to the figures in your manual, with your own gauge.
Brake drag. With the bike safely supported, spin each wheel. It should rotate freely. A binding caliper wastes fuel continuously and generates heat — feel the disc after a ride, and if one is noticeably hotter than the other, investigate.
Chain condition. A dry or over-tightened chain absorbs power.
Cheap to check
Air filter. A clogged filter restricts airflow. Inspection is straightforward on most machines and the part is inexpensive. Follow the interval in your manual.
Spark plugs. Worn plugs cause incomplete combustion. Also worth doing because the plug tells you a story — its colour and condition indicate how the engine is running, which is diagnostic information you cannot get any other way.
Needs a workshop
- Fuel injection or sensor faults. A failing sensor can richen the mixture without triggering a warning light
- Valve clearances out of specification. Follow the interval in your manual — this affects both economy and long-term engine health
- Fuel leak. Rare, and serious. Any smell of fuel means stop and investigate immediately
When it is not the bike
Two honest possibilities worth considering before spending money:
Riding style. Consumption is heavily influenced by throttle use, cruising speed and how much you use the gearbox. A change in your riding — even an unconscious one after gaining confidence — shows up at the pump.
Running in. Consumption often improves over the first few thousand kilometres as the engine beds in.
Post your figures
Code:
Model, year, mileage:
Consumption before and after:
Dashboard or calculated at the pump:
Riding type and typical speed:
What changed around the same time:
Tyre pressures when you checked:
What it turned out to be: