From the point of view of the shape and position tolerance of the parts: the dimensional tolerances of the same set of parts are not within the same range; the top pin holes of the parts are rough, and the positioning holes and pin deflections are installed; a group of evenly distributed holes are individually skewed and have different pitches. Failed parts. For example: Piston pins, shafts, valves, etc. From the point of view of the performance of the parts: If the switch type parts can simulate the working state to carry out the operation experiment, all those with poor hand feeling and large pulling resistance are the unqualified parts. Some elastic parts can be tested by pulling, pulling, and pressing. Any feeling that is too soft or hard, and the free height is inconsistent, can be judged as inferior accessories. For example: valve springs, oil pumps, various valves, air pumps, etc. From the point of view of the material selection of parts: replace cast steel with inferior cast iron; use low carbon steel instead of alloy steel and high strength carbon steel; use ordinary recycled plastic instead Engineering plastics; Use ordinary rubber instead of high temperature, high speed rubber; Recycled rubber instead of synthetic rubber, etc., are all inferior parts Conditional metallographic experiments and hardness testing (Experienced masters can listen to their sound by tapping Identify it). For sealed parts, such as oil seals, where the color is bright, the size does not meet the national standard, too soft or hard, are unqualified products. The identification of imported accessories: The characteristics of unqualified or non-imported accessories are that the packaging is full of foreign language or has obvious grammar and word errors; the packaging is rough and there are no sales restrictions, no sign of access, etc.; the accessories have no serial number of the product, and the processing technology Rough or obvious traces of heat treatment and so on. Qualified Internet access, purchase of high-quality auto parts. Note: Be sure to remove the oil seal or retaining ring before welding to prevent burnout. In addition, be sure to pay attention to safety when cutting and drilling. The separation bearing fitted with the grease nipple is mounted on the car. One person uses the screwdriver to rotate the release bearing (from under the flywheel housing) so that the grease nipple is facing downwards; the other person moves the clutch to the clutch pedal in the cab. Fill the grease gun with the extension rod (2 to 3 times), then release the clutch pedal, separate the bearing in several revolutions, and then step on the clutch pedal to inject the oil once, so that the injected lubricant is evenly distributed, and the lubrication effect is better. The grease fitting is installed. After the separation bearing is mounted on the vehicle, the service life of the automobile clutch release bearing can be extended to 5-6 years as long as the oil is injected once. Even if the engine is overhauled or replaced with a friction plate, the separation bearing does not need to be replaced. An electric city bike is a type of bicycle that is designed for urban commuting and transportation. It is equipped with an electric motor and a battery that provides assistance to the rider while pedaling. This makes it easier to climb hills, ride longer distances, and carry heavier loads.Electric city bikes typically have a comfortable upright riding position, fenders, lights, and arack for carrying bags or cargo. They are a popular choice for people who want a convenient, eco-friendly,and affordable way to get around the city.Electric City Bike is Made for the people who like riding ebikes to work , school or just for fun.This bike is designed to be efficient,comfortable and reliable,making it the perfect choice for daily commuters.With its powerful motor and long-lasting battery,you can easily travel long distances without worrying about running out of power. The bike features a lightweight aluminum frame, front and rear suspension, and a comfortable saddle to ensure a smooth and comfortable ride. It also comes equipped with a range of safety features, including front and rear lights, a horn, and disc brakes for reliable stopping power. Whether you're looking for a fun way to get around town or a reliable mode of transportation for your daily commute, the Electric City Bike is the perfect choice. Electric City Bike,Charge City Ebike,Ebike City Bike Ejoysport Technology (SuZhou)Co.,LTD , https://www.nbtoperiding.com