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!



Air Inlet

The Air Inlet on your imported chinese QMB139 motorbike or scooter constists of the air filter and ducting that leads up to the carburetor. Restricting the air inlet can reduce the performance of an engine as an engine requires plenty of air to mix with the fuel. This is a more common restriction on 2 stroke scooters and motorbikes.

Checking your 4 stroke scooter or motorcycle for a restricted air inlet

Applies to: Baotian, Sukida, Hoatian, Lifan, JMStar, Jinlun, Kymco, Tank, Quinqzi, PGO, Roketa, Strada and Taishan QingQi and many more...

Motorcycle Air Inlet Restrictions

It is quite rare for a 4 Stroke 50cc Scooter, Chinese or not, to have a restrictor on the air inlet, as this would increase the vacuum in the slide type carburetor and effect the fuel/air mixture. However, it is not impossible and if you have exhausted all other restriction possibilites with no positive results, checking the inlet ducting for obstructions is the next step.

Removing the air filter and plastic ducting is quite a simple process. You will usually require a cross head screwdriver and an 8mm ratchet/spanner. Also, some scooters may differ slightly but these instructions should be adequate for most scooters.


  1. Use a screwdriver to undo the screws that secure the airfilter cover to the airfilter housing. Take the AirFilter Cover Off A GY6 Chinese Scooter 4 Stroke
  2. You should now be able to see your scooters air filter element. Remove the airfilter and inspect the air inlets for obstructions or restrictions. Looking for four stroke air ducting restrictions, motorcycle.
  3. To get a closer look, you may wish to completely remove the airfilter housing from your 50cc scooter. It is secured to the scooter by a couple of 8mm bolts that are easily removed. You will have to disconnect the air inlet from the carburetor, use a cross head screwdriver to release the clamp from the carburetor inlet, you should now be able to completely remove the air filter housing from your motorbike. Check thoroughly for blockages or restrictions. Disconnecting your imported scooters carburetor inlet.










Notes

Most running problems associated with chinese imported clone scooters relate to the fuel/air system. We do not recommend customising the air inlet system, either with a performance air filter or by modifying your stock air filter and housing.

If you do modify your stock air filter and housing, do it in such a way that you can reverse the changes later and return the scooter motorbike to its factory settings.



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