After the motorcycle is disassembled or decomposed into parts, the parts should be cleaned first.
Remove oil stains. There are two types of cleaning methods for metal parts: cold washing and hot washing. Use kerosene or gasoline as a cleaning agent, put the parts in a container, and scrub with a brush, which is called cold washing. Use alkaline solution as a cleaning agent, heat the parts in a container and the cleaning agent to 70~90℃ for 10~15 minutes, take out the alkaline solution on the surface of the parts with clean water, which is called hot washing method. The cold washing method has simple equipment, simple and rapid operation, but high cost and easy to cause fire. The hot washing method has low cost and will not cause fire. However, when washing, avoid splashing alkaline water on the skin, otherwise it will damage the human body. To clean aluminum alloy, a solution must be prepared, otherwise the aluminum alloy parts will be corroded.
For the cleaning of non-metal parts, different cleaning methods should be used according to different parts materials. If rubber parts should be cleaned with alcohol, they should not be cleaned with kerosene or gasoline to avoid rubber expansion and deterioration. The clutch friction lining and brake shoe friction lining should be washed with gasoline instead of alkaline solution.
Remove carbon deposits. Two methods can be used to remove carbon deposits: one is mechanical method, which uses bamboo scrapers and spatulas to remove carbon deposits; the other is chemical method, which is to put parts in a chemical solution and heat to 80~90℃ Boil for 1~2 hours to soak and soften the carbon deposits, and then brush it off with a brush. After removing the carbon deposits, use hot water to clean the chemical solution on the parts. When cleaning carbon deposits on cast iron and steel, lubricating oil should be applied in time after washing to prevent corrosion.
After the motorcycle parts are cleaned, parts inspection should be carried out. The purpose of the inspection is to determine whether the parts need to be repaired or scrapped. There are three methods for detecting parts: direct inspection, inspection and inspection.
1. Direct inspection method. The direct inspection method does not require instruments and other tools, and only relies on human sensory organs to inspect and judge the technical status of the parts. This method is simple and easy to implement and is widely used in motorcycle maintenance.
(1) Visual inspection method: carefully observe the surface of the part with the naked eye to determine whether the part has serious wear, cracks, peeling, surface annealing, ablation damage, bending deformation, etc. For rubber parts, check whether the rubber has deteriorated.
(2) Comparison method: compare the new standard parts with the tested parts, and determine the technical status of the tested parts by comparison.
(3) Acoustic method: Whether certain disc parts or various boxes in the motorcycle have cracks, whether the parts connected by rivets are loose, and the welds of the welded parts of the frame, all can be hit with a small hammer Listen to the sound. If the sound is crisp, the technical condition of the part is intact; if the sound is hoarse, it means that the part has cracked or the joint is loose.
2. Test method. Measuring the changes in the size and geometric shape of the parts by measuring tools and instruments can obtain accurate data. The technical condition of the part can be determined by comparing the allowable limit range. This method has high accuracy, but the accuracy of the measuring tool must be carefully checked before the test and the measuring position must be selected reasonably.
3. Detection method. The detection method for hidden defects of parts can be used. In motorcycle maintenance, the simplest oil immersion hammering method is generally used, that is, the tested parts are soaked in kerosene or diesel for a few minutes, and then the surface of the parts is wiped dry, and the talcum powder is evenly sprinkled on the parts. On the surface, then use a small hammer to gently tap the non-working surface of the part. Due to the vibration of the parts caused by the hammering, if the parts have cracks, the oil stains immersed in the cracks will splash out and stain the talcum powder on the surface, so that a yellow line mark appears at the crack.