Index
Overview
Tuning
Tuning Overview
Lighter Roller Weights
Remove Variator Restrictor
Stiffer Clutch Springs
Move Needle Jet Washer
Increase Fuel Jet Size
Carb De-restriction
Un-Restricted CDI Unit
Un-Restricted Air Inlet
Trouble Shooting
Compression Test
Fuel Enricher Test
Seized Brake Caliper
General Maintenance
Replace Air Filter
Check & Change Oil
Spark Plug Change
Idle Speed Adjust
Change Brake Pads
Adjust Valve Lash
Electrical
Testing the Battery & Charging System
Battery Change
Coil Change
HT Lead Change
Transmission
Remove Starter Motor
Refurb Bendix Gear
Engine
Camshaft Removal
Valve Removal
Replace Valve Guides
Engine Removal
Return to Transport Listings
Models Covered
Lexmoto, Pulse, Sukida, Baotion, Lifan, Direct Bikes, Huatian, JMStar, QT50, LF50QT, YH50QT,
BT49qt, 139 QMB, Honda, GY6, Motorbike, Taishan, Jonway, Peugeot V-Clic, QT-4, QT-7, QT-9, qt-11, QT-50
Kymco, Tank, Quinqzi, PGO, Roketa, Strada, Vento, Yamati, QMB139, SunL, SYM, QingQi, Volano Plus Many More Chinese Motorcycles, mopeds and
scooters!
HT Lead and Coil
The HT Lead and coil are usually and all-in-one unit in your imported Chinese Taishan or Baotian 50cc scooter. The Coil converts the low voltage signal from the CDI unit into a very high voltage/low current and the HT lead (High Tension Lead) carries the high voltage to the spark plug. Both are likely to be of poor quality on imported chinese scooters such as Tank, Baotian and Jonway.
These parts are cheap for chinese and taiwanese 50cc honda clones so it is worth keeping a spare under the seat just in case.
How to Change The Coil and HT Lead, Chinese QMB139 Scooters
Applies to: Baotian, Sukida, Hoatian, Lifan, JMStar, Jinlun, Kymco, Tank, Quinqzi, PGO, Roketa, Strada and Taishan QingQi and many more...
Checking and changing your chinese 4 stroke scooters HT Lead and Coil
Changing the Coil and HT Lead on your scooter is a fairly simple task. Some scooters may have bodywork or fittings that impede access, in which case you may have to remove the panels to give yourself room to work.
A suitable Coil and HT Lead can be obtained for your 139QMB moped either online or from reputable scooter dealers. On most scooters the HT Lead and Coil are an all-in-one unit. These Coil/HT Lead units are identical on most Chinese imported 50cc scooters.
- Place your motorbike on its center stand. In these pictures I have removed some bodywork for camera access, this is not always necessary. The HT lead attaches to the spark plug on the side of the engine and the coil is screwed to the frame on the same side as the exhaust.
- Pull the High Tension Lead (HT Lead) from the top of the spark plug.
- Now follow the HT lead along the Scooters frame until it reaches the coil, usually above the exhaust. Undo the single locating screw or bolt and disconnect the two wires (usually one green and one black), noting their positions.
TIP: when refitting the coil their is a locating lug on the mounting point on the moped frame that holds the coil in the correct position.
- You should now be able to remove the old coil and ht lead from the scooter and fit the replacement.
Notes
Poor running, difficult starting or not starting at all are all symptoms of a broken coil or ht lead. Even if you see a spark when you remove the spark plug it does not mean that the coil is OK. The spark on your Baotian, Sukida, Taishan or any other chinese 50cc scooter may be too weak or being delivered at the wrong time.
Most 4 stroke 50cc clone scooters such as Baotian and Tank and motorbikes and pitbikes use very similar coils.