Reinstall the drain plug tightly. Pour 0.8L of fresh 10W-40 oil into the dipstick fill hole. Check the level without screwing the dipstick in. Carburetor Tuning & Cleaning

Hold the grounded threads of the plug against the bare metal of the engine cylinder head.

The small rectangular CDI box is the brain of the ignition system. If all switches are functional but there is no spark, the CDI box is the most common point of failure and is inexpensive to replace.

| Specification | Details | |---------------|---------| | | 125cc, 4-Stroke, Single Cylinder, Air Cooled | | Bore & Stroke | 52.4mm x 57.8mm (Approx.) | | Compression Ratio | 9.0:1 (Approx.) | | Fuel System | Carburetor | | Ignition | CDI (Capacitor Discharge Ignition) | | Starting System | Electric Start | | Transmission | Semi-Automatic (No clutch lever) or fully automatic, depending on the specific model | | Drive | Chain Drive | | Front Suspension | Double A-Arm with Hydraulic Shock Absorbers | | Rear Suspension | Swing Arm with Hydraulic Shock Absorber | | Front Brakes | Drum Brake | | Rear Brake | Hydraulic Disc Brake | | Front Tire | 19x7-8 | | Rear Tire | 18x9.5-8 | | Battery | 12V/5AH | | Fuel Tank Capacity | Approx. 2.5 liters | | Max Speed | ~45 km/h |

A loose chain will derail and smash into the engine casing, causing severe damage. A chain that is too tight will ruin the transmission output bearings.

: Gravity-fed via a 3-position fuel cock (ON/OFF/RES).

There are a few HB 125 models, such as the HB-ATV125F and the HB-ATV125B . While their chassis may differ slightly, the engine and transmission systems are virtually identical, so this guide applies to them all.

Remove the bowl and clean jets with carburetor cleaner.

This points to a fuel delivery or ignition problem.

The challenge of finding a specific service manual for an HB ATV 125 is a common one among owners.

Insert a feeler gauge between the valve stem end and the rocker arm adjuster screw. 0.05mm (0.002 in) Exhaust Valve Clearance: 0.05mm (0.002 in)