Why Your 2017 Suzuki GW250 Is Using More Fuel Than It Used To
Shop parts for a 2017 Suzuki GW250 Motorcycle.
The 2017 Suzuki GW250 is a 248cc four-stroke parallel twin with liquid cooling, electronic fuel injection, and chain final drive. That combination shapes the entire list of reasons it might start drinking more fuel than it used to. There is no choke to leave partly closed, no float bowl to stick, and no jets to gum up. Instead, the GW250 depends on sensors, injectors, and an engine control unit to decide how much fuel to deliver, and anything that skews those inputs — or that adds mechanical drag — eventually shows up at the pump.
Start by Confirming the Drop Is Real
Before chasing a mechanical cause, make sure the numbers actually changed. Fill the tank to a consistent level, reset the trip meter or write down the odometer reading, ride normally, then refill at the same pump and note how much fuel went in. Divide the distance ridden by the fuel added and you have a real figure for that tank. A single tank proves very little, because wind, traffic, and temperature can swing the result noticeably. Track three or four consecutive tanks before you conclude anything.
It is also worth checking whether the bike is telling you the truth. If you have changed tire sizes or swapped sprockets, the speedometer and odometer readings shift with them. A taller rear tire or a smaller rear sprocket makes the odometer under-report distance, which makes your calculated economy look worse than it really is. If you have not touched either, and you simply find yourself stopping for fuel more often than you used to, that is still a valid signal — just confirm it with a few measured tanks.
Riding Conditions and Habits That Quietly Cost Fuel
Not every fuel economy drop is a fault. Cold weather thickens lubricants, increases warm-up enrichment, and raises air density, all of which cost fuel. Many regions also switch to a winter fuel blend that simply contains less energy per gallon. Ethanol-blended fuel has a similar effect, and the higher the ethanol content, the more noticeable it becomes.
Your right hand matters just as much. Sustained highway speeds, hard acceleration away from stops, and carrying a passenger or loaded luggage all increase the fuel the engine needs to do the same trip. Short hops are especially thirsty, because the GW250 spends a larger share of each ride warming up and running rich. Long idle warm-ups in the driveway burn fuel while covering zero distance, which drags your calculated economy down without anything being wrong with the bike.
Tires, Brakes, and the Chain
Underinflated tires are the most common and most overlooked cause of poor fuel economy on any motorcycle. Soft tires flatten at the contact patch, raising rolling resistance, and the effect compounds over a full tank. Check pressures when the tires are cold and recheck monthly, since tires lose air gradually and a slow leak can go unnoticed for weeks.
A brake caliper that drags will do the same thing, and it is easy to miss. After a ride, carefully feel the brake discs. A disc that is noticeably hotter than the others, or a wheel that is hard to spin by hand with the bike on a stand, points to a sticking caliper or a misadjusted brake. Because the GW250 is chain driven, the final drive deserves attention too. A dry, rusty, or overtightened chain soaks up power that should be reaching the rear wheel, and an overtightened chain also loads the countershaft bearing. Clean, lubricate, and set the chain to the correct slack, and make sure the rear wheel is aligned properly afterward.
Air Filter and Spark Plugs
A clogged air filter restricts incoming air, and the engine control unit responds by trimming fuel delivery in a way that leaves the mixture richer than ideal. If the filter is heavily soiled or has not been serviced in a long time, replacing it is inexpensive and often restores both throttle response and fuel economy.
Spark plugs matter for the same reason. Plugs that are worn, fouled, or gapped incorrectly produce a weaker spark and incomplete combustion, so some of the fuel you paid for leaves the engine unburned. Pull the plugs and read them. Sooty black deposits suggest a rich condition worth investigating further, while normal light tan or gray coloring suggests the plugs are not the problem. The GW250 uses a fully electronic ignition, so there are no contact points to wear or timing to drift, but the ignition system can still degrade through a weak coil, a damaged plug cap, or a poor ground connection.
Fuel Injection, Sensors, and Injectors
On a fuel-injected bike like the GW250, the engine control unit decides fueling based on sensor input, so a sensor that lies will change how much fuel the engine receives. An engine coolant temperature sensor that reports the engine as colder than it actually is will keep the system in enrichment mode, and the bike will run rich long after it should have settled into normal operation. If your bike is equipped with an oxygen sensor, a lazy or failed sensor can have a similar effect by misreporting the exhaust mixture.
Dirty or leaking injectors are another possibility. An injector that does not seal properly dribbles fuel when it should be closed, and one that is partially clogged sprays poorly, both of which hurt economy. Because the GW250 is a parallel twin, it uses separate throttle bodies, and if they drift out of synchronization the cylinders will not share the load evenly. Stored fault codes can point you straight to a sensor problem, so having the system scanned is a sensible early step. Finally, check for fuel leaks — a weeping line, a loose clamp, or a seeping fitting wastes fuel and is a genuine safety concern.
Engine Condition and Cooling System
As an engine accumulates miles, compression slowly drops through ring and valve wear, and lower compression means less of the fuel's energy becomes forward motion. Valve clearance that has drifted out of specification has a similar effect, since valves that do not seal fully bleed off cylinder pressure. A compression or leak-down test will tell you whether the engine itself is the source of the problem.
Because the GW250 is liquid cooled, the thermostat is worth a mention. A thermostat stuck open keeps the engine from reaching full operating temperature, and a cold engine needs more fuel than a warm one. If the temperature gauge or indicator never seems to reach normal, or the bike runs cool in mild weather, that is worth having checked.
Modifications That Upset the Fueling
An aftermarket exhaust or a high-flow air filter installed without matching fuel tuning is a frequent culprit. These parts increase airflow, and if the fueling is not adjusted to match, the engine can end up running rich in some conditions and lean in others. If the mileage drop began right after a modification, that timing is your best clue.
When to Hand It to a Mechanic
Some symptoms point to something deeper than a maintenance item. A strong fuel smell, black smoke from the exhaust, sooty spark plugs, rough running alongside the mileage drop, or a dashboard warning light if your bike has one all justify professional diagnosis. The same goes for a fuel economy drop that persists after you have corrected tire pressures, serviced the chain, replaced the air filter and plugs, and confirmed your riding conditions have not changed. At that point, a mechanic with the right diagnostic tools can check sensor readings, injector performance, and engine health far more efficiently than guesswork.
Related Shopping Categories
Shop Fuel System Parts for a 2017 Suzuki GW250 Motorcycle.
Shop Air Filters for a 2017 Suzuki GW250 Motorcycle.
Shop Tires for a 2017 Suzuki GW250 Motorcycle.
Shop Brake Parts for a 2017 Suzuki GW250 Motorcycle.
Shop Spark Plugs for a 2017 Suzuki GW250 Motorcycle.
Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.
