Engine overhaul characteristics
Due to the two stroke engine and four stroke engines of existing structures, these differences of two kinds of engine fault diagnosis and maintenance characteristics are different. Now, with engine power for accelerating performance is poor fault.
Engine power shortage, accelerate the poor performance of the fault, affect a wider range of engines, almost involves various systems. In order to express convenient, motorcycle ignition system, will drive system and cylinder piston factors excluded. Two-stroke and four stroke engines is mainly due to the above faults with gas mixture institutions, seal, its diagnosis and maintenance of the basic ideas and have different features.
1, troubleshooting and four stroke engines
A) distribution institution
Four stroke engines with gas installation of institutions have strict regulations, assembly will only when the timing marker flywheel magneto scribed line on the crankcase (or box) timing marker holes in this position parallel to install the camshaft, timing chain and timing chain. If the engine is after dismantling assembly gas powered, timing after accelerating performance of fault, as long as carefully proofread and timing can eliminate xinan assembly gas fault. If a motorcycle is running after the failure tens of thousands of kilometres, and often need adjusting valve clearance, and with abnormal sound of cylinder head, engine failure to start, should be suspected appear abnormal wear or camshaft gas distribution institution and its related parts, shall be fully appear serious leakage inspection: 1) the camshaft wear: engine running for a long period of time, for lubrication and cooling system anomalies or parts, and the quality problem of itself from other some uncertain factors, camshaft lift wear parts, use limit, the more worthy of gas phase Angle will be reduced, now that matchs gas phase change, Two axis and the camshaft or severe wear bushing holes in turn, make the camshaft process of radial displacement, causing the valve open degree, valve open. These two conditions will cause the engine to the low speed characteristic direction, motorcycle and acceleration performance deteriorated nature. And with the gas distribution agencies operating noise increased gradually. 2) valve leakage: if the influence of many factors, because appear valve ablation, the valve stem bending, valve spring elastic abate wait, the intake and exhaust door will seal leakage phenomenon, lax. The reasons are: with the valve seat valve, due to excessive carbon sealed, combined with the valve seat valve sealing and produce the valve clearance is too small or no clearance to valve mechamisms, open late early, engine temperature, expands natural elongation automatically open valve, valve closed lax, caused by leakage. Valve closed lax, and is likely to cause the valve spring down the stretch, therefore, the valve leakage, not easily neglected during the check valve spring of elasticity.
B) cylinder liner airtight: not according to stipulations in the cylinder head bolts or tightening torque value, or driving nuts tens of thousands of kilometres of cylinder head after the nuts and bolts of causes for loose, The cylinder block surface or on the plane processing technical requirements and reach the flatness of the serious, Gas cylinder and the cylinder engines work after the plane in thermal deformation and warpage, Cylinder cushion on both sides of the coated with rubber gasket (off) coated butadiene-acrylonitrile rubber, Cylinder liner place, can make the mixture airtight have thin, loss of engine power.
C) intake place flat: if the intake manifold rubber parts for aging metamorphism produce craze, or between the cylinder and inlet O ring aging, or failure to tighten intake no provisions, can produce torque leakage phenomenon, in the engine at work, in the air mixture have thin, power decline.
Two stroke engines, troubleshooting
A two stroke engine) of the institution in the cylinder block or major setting and its distribution in the crankcase position basic cannot change. If the mixture of overmuch, after combustion engine components of carbon in hongcun gas cylinder clogging, interference engine exhaust gas and normal esau, make the engine exhaust, resistance. Therefore, to drive the car tens of thousands of kilometres, should focus on the check whether the exhaust air cylinder is blocked. In addition, if the exhaust muffler overmuch, also in carbon emissions will increase the exhaust resistance, causing the loss of engine power.
B) two stroke engine determines the structure characteristics of the sealing of the crankcase (including inlet, carburetor) there can be no leakage. If the crankcase seal leakage, will make the lax caused by engine ignition mixture decreases, suction is thinning, and power. Check the key is: left and right side of the crankcase leakage (mainly with super flatness sealant liquid or failure), or the crankshaft, oil seal serious aging lips mouth and crankshaft journals in seal leak, or lax valves and reed reed, and warpage seat over the seat rubber layer and layer not petrol, make seal failure. In addition, the crankcase sealed, it will cause car difficult starting fault. Cold
C) two stroke engine and four stroke engines matching different types, the carburetor carburetors idle oil have differences. In the adjustment of the two-stroke carburetor idle air conditioning screw counterclockwise, to spin the idle air conditioning screws, is increasing oil into the idle, the air mixture will become loose, The spin clockwise idle air conditioning screws, is to reduce the idle oil into the air quantity, the mixture will become strong. If the air quantity into the carburetor excessive (especially in the cold winter), will directly influence the engine and accelerating performance. Therefore, in the regulation according to climate change, usually in mastering to slant a bit stronger winter, according to the provisions of vehicles using manual idle air conditioning screw clockwise to spin a bit, Summer adjust to dilute some (idle air conditioning screw counterclockwise to spin. Its adjustment quantity, to slow increase throttle withtheengine for standard.
To sum up, because the four-stroke engine and two stroke engine working principle, structure, its repair methods and features are different. For four stroke engines, should check whether the oil pump, by foreign bodies blocked filter to ensure unblocked, adhere to the road of the lubricating oil changing process. Tens of thousands of kilometers of road vehicles for, if discover the engine, and accelerating performance and exhaust clearance should be adjusted, its operation often sound also growing, should check the camshaft lubrication and wear, and the cylinder liner, and whether there are ageing intake in cracking and anomalies, emotion change damaged parts. For two stroke engine oil pump, it must ensure that its oil can work normally, the moderate flow of specific situations, adjust the mixture proportion; the carburetor, Check whether the crankcase on existing, and regularly cleared sealed chamber, spark plug, cylinder and intake and exhaust and exhaust muffler carbon, in order to ensure the smooth and clean, direct vent.