Inlet air filter is blocked
Specific reasons: the rubber pipe is bent and blocked by air, and the foam plastics in the air filter is blocked by dust, which is seriously rich in oil caused by the blockage of air intake.
Repair: Trim the intake pipe and clean the foam from the empty filter. If the air filtration is normal, adjust the carburetor so that it is not seriously rich
The carburetor is not properly adjusted
Specific reason: the main oil content hole is blocked by impurities caused by high speed oil. High speed oil enrichment caused by dust blockage of the main oil distribution orifice. The carburetor choke is still in the cold start position. The carburetor main oil needle is out of position. Carburetor diameter is too small. High speed rich oil blocked by empty filter.
If the carburetor's air adjustment screw is not adjusted properly, the main injection needle is too low, or the float chamber oil level is too low, resulting in too thin mixture, the carburetor will be shut down and temper.
Exhaust pipe is blocked
Specific reasons: the exhaust pipe is blocked by carbon ash, and the bending part of exhaust front section is dented; These cars have no problem moving at low speed, but not at high speed.
Repair method: remove the exhaust pipe, clean the spring with sewer or hand electric drill clamp wire rope scraping the internal carbon, filling high quality gasoline. The impure substances in gasoline such as wax and gelatinous bai substance are the main components of carbon deposition, so the tendency of carbon deposition in gasoline with high cleanliness is weaker.
Camshaft installation dislocation or alignment disorder
Specific reasons: the timing of small chain installation dislocation, resulting in the exhaust time too late. Camshaft alignment disorder, resulting in poor intake and exhaust timing.
Repair: If the installation is confirmed to be a dislocation, re-install the camshaft is. If camshaft alignment is off, polish or repurchase.
The exhaust channel of the four stroke cylinder head is seriously carbonized
Specific reason: Carburetor long-term serious rich oil. The ignition Angle of the igniter is not correct for a long time. Long-term use of non-standard fuel. The engine burns oil.
Repair method: remove the cylinder head, with a small flat driver shovel clean cylinder head exhaust channel inside the carbon layer; And adjust the carburetor. Either switch to a plunger carburetor or adjust the carburetor to a depleted oil state and slowly burn off the carbon deposits.
The exhaust passage of the two punch cylinder is seriously carbonized
Specific reason: Carburetor long-term serious rich oil. The ignition Angle of the igniter is not correct for a long time. Long-term use of non-standard fuel. Use a mixture of oils.
Repair: If confirmed, remove the cylinder head, move the piston to the bottom dead center, and use a small flat driver to remove carbon in the cylinder head exhaust channel. Or use a plunger carburetor. Adjust the carburetor to lean oil. Reduce the use of lubricants. Clean up regularly.
The igniter does not give an early ignition Angle
Specific reason: ignition advance Angle is too small. The original model was made of 70 # gasoline, and the new flywheel has a different trigger boss. I had encountered such a flywheel, but I did not expect it at that time. There was also abnormal damage to the firearm, turning it into a fire along the rear of the triggering platform.
Fix: If you can't find the original standard flywheel, modify the trigger boss by yourself, or make your own "dislocation key" to trigger the boss. The flywheel should find the upper dead point of the piston, and then measure the position between the trigger boss and the igniter sensor. It should be 26 ~ 30 degrees. It is difficult to check the trigger boss for some two - punch or four - punch girder cars. It can be seen from the performance of the engine at each speed stage.
Slight engine wear
Specific reason: the size of the friction velocity
Repair method: in the cold car start, can be in front of the first gear, pinched clutch trolley on 30-40 meters, and then hang the neutral gear, release the clutch, turn on the electric switch, close the choke, after the normal start car, so as to reduce engine wear.
Electroplating parts rust
Specific reasons: in the forming process of the metal parts, the surface may be stained with oil or form rusts, oxides, etc., forming an intermediate layer between the surface of the parts and the plating solution, which hinders the smooth progress of the electrode reaction, thus affecting the binding force of the coating and the matrix and the coating quality; When the surface of the metal rough, and there are pores, holes, cracks and other defects, plating solution is easy to remain in the front defects, resulting in the deposit appears "black spot" or "white point", or due to the acid corrosion of hydrogen so that the deposit appears "bubble". Secondly, rough or machining defects on the surface of parts, not plated smooth, shiny coating. When there is dust, metal powder on the surface of the parts, the coating will appear "nodules" and "burr", easy to fall off, so that the coating surface produce pits.
Repair method: put ammonium acetate into equal amount of clean water to heat to 70 degrees, and then use soft cloth to thoroughly scrub the rust, until the rust completely disappeared, dry with dry cloth can be.
The fuel tank rust
Specific reasons: Normally in the case of frequent use without long-term placement, due to the gasoline in the tank, so it will not rust, if it is not used for a long time, this may be possible.
Repair method: when cleaning, first let off the excess gasoline, leaving only half tank, and then remove the oil level sensor, put a thin piece of iron chain into the tank, the end of the chain with a rope left outside, and then shake the tank, so that you can basically clean the rust inside down. Finally, pour in the gasoline, shake it and wash it several times.