Many running faults only show up on the road: under load, at a certain speed, when hot, or over bumps. A planned road test lets you see exactly when the fault happens. That information narrows the diagnosis more than any guess. Do a short test before a repair (to confirm the fault) and after it (to prove the fix).
Safety
- Most serious workshop injuries happen on test rides. Wear a helmet and protective clothing every time, even for a short test.
- Do the Pre-ride check first: brakes, tyres, lights, throttle snap-back, chain. Never road test a bike with weak brakes, a fuel leak or a throttle that sticks.
- Choose a quiet, legal route. Watch the traffic, not the bike. A road test is not a speed test.
- If the engine cuts out, signal, move to the side and stop safely before you look at anything.
- Do not test a customer's bike without permission.
Steps
Plan the test
- Ask the rider or decide yourself: what exactly happens, and when? Cold or hot? At idle, in the middle, or at full throttle? In which gear? Uphill, with a passenger, in rain, over bumps?
- Check tyre pressure and that the wheels spin freely on the stand (a dragging brake feels like a weak engine; the K-Light 125 power fault chart starts here).
- Note the fuel level, the warning lights at key-on, and the odometer.
During the test
- Start cold if the fault is a cold one. Note how it starts and idles.
- Pull away gently in first gear. Note any hesitation or judder.
- Accelerate through the gears at part throttle, then at full throttle in a middle gear. Listen for misfire, pinking (a light metallic rattle) or bogging.
- Hold a steady speed for a minute in top gear. Feel for surging or jerking.
- Roll the throttle off. Note popping from the exhaust and whether the revs fall back cleanly.
- Climb a hill if the fault is power-related. Watch whether engine revs rise without the bike speeding up (clutch or CVT slip).
- Ride long enough to reach full temperature, then repeat the step where the fault appeared. Note if it changes when hot.
- Ride over a rough patch at low speed if the fault is a cut-out.
- Stop and idle for a minute when hot. Note any stalling or rising idle.
After the test
- Write down what happened at each step while you remember it.
- Check for new leaks, smells and warning lights. Feel nothing hot with bare hands.
- Use your notes to choose the problem page: for example Misfires when accelerating hard, Power fades as the engine gets hot or Engine revs rise but the bike does not speed up.
Check your work
- After a repair, the same route and conditions no longer bring back the fault.
- No new leaks, noises or warning lights after the ride.