If your bike, whether it’s a Honda CD 70, CG 125, Chinese 70cc,or any other, is suddenly consuming more petrol, it’s probably not because your motorcycle is getting old and it can even happen to the best fuel average bikes in Pakistan. There can be many common reasons behind decreased fuel efficiency of bikes. Let’s explore some reasons why the fuel efficiency of a bike drops and how to improve it.
Clogged Air Filter
In cities like Lahore, Karachi, and Pindi, airborne dust is terrible. That dust quickly clogs a bike’s air filter, choking airflow to the engine. Worst case? If you don’t change the air filter regularly, it can even pass the filter and even start to build up in the engine.
- Fuel loss: 2% to 10%
- Example: A CD 70 usually giving 55 km/L could drop to 50 km/L on a dirty filter
- Tip: Clean or replace filters regularly (every month)
Low Tire Pressure
Did you know that under-inflated tires decrease fuel efficiency? Why? Well, under-inflation increases rolling resistance adding extra burden on the engine due to which, it burns extra petrol.
- Fuel loss: Roughly 1% per 2 PSI drop
- Example: Dingy tires could drop a CG 125 from 40 km/L to 38 km/L
- Tip: Check pressure every 2 weeks, psi gauges cost around Rs. 200 locally
Dry or Dirty Chain
A dry chain causes friction, forcing the engine to work harder. It can reduce the fuel efficiency by up to 5%. Wondering why? It increases resistance between chain and sprocket adding more burden on the engine resulting in decreased mileage.
- Fuel loss: Around 5%
- Tip: Clean and oil the chain every 300–500 km, or twice a month
Dragging Brakes
One of the major causes of dropped bike fuel-average is dragging brakes. If your brakes rub even slightly, your engine continuously fights back resistance. That inefficient drag can cost you around 5% in fuel economy on average.
- Fuel loss: 5% to 10%
- Tip: Lift rear wheel, spin it; if it doesn’t spin freely, get the brakes checked
Engine Wear: Rings & Valves
This is more serious and needs mechanical attention. Worn rings or improperly set valve clearances can cause excessive oil burning and loss of compression. As a result, you may even face a 20% to 30% decrease in fuel efficiency. For a CG 125 normally getting 35 km/L, that’s a drop to 25–28 km/L, a massive loss you’ll feel at the pump.
- Fuel loss: Huge 20% to 30%
- Tip: If your bike smokes or burns oil, get a mechanic to do a compression test and check valves
Poor Fuel Quality (Adulteration)
In Pakistan, petrol adulteration is unfortunately quite common. Adulterated petrol reduces combustion quality and may also damage the engine in the longer run. As a result, it may even lead to 10% to 20% lower fuel efficiency.
- Fuel loss: 10–20% .
- Tip: Use trusted pumps—Shell, PSO, or local station brands you believe in.
Old or Wrong Engine Oil
Using the wrong oil grade or postponing oil changes increases engine friction. That results in a roughly 5% to 7% drop in mileage. Changing your oil every 800 to 1,000 km (or as per recommended by the manufacturer) with manufacturer‑recommended oil can recover that lost efficiency easily.
- Fuel loss: 5% to 7%
- Tip: Stick to the oil grade recommended by the company and change it regularly
Harsh Riding Habits
Fast starts, sudden braking, and riding with low gears burn extra fuel.
- Fuel loss: About 2% to 10%
- Tip: Smooth acceleration, gentle braking, and using the right gear help, ride around 40–55 km/h for best efficiency (follow the speed limits of each road)
Final Verdict
Pakistani riders can reclaim 5% to 30% of lost mileage with simple steps: clean filters, inflate tires properly, lube chains, get occasional mechanical checks, and ride smoothly. Trusted fuel and proper oil also play big roles. These small habits cost little but can mean hundreds saved each month at today’s petrol rates.
Do you know any other problem that maybe causing decrease in the fuel efficiency of your bike? Share with us in the comment section below.
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