Yamaha Motorcycle Engine Parts
Hangzhou UCAN Trading Co., Ltd
We are prefessional motorcycle spare parts manufacturer &exporter, establlished in Hangzhou since 2009.We have been exporting parts to different countries for many years.We mainly products is full body fairing parts forscootermotorcycle(mainly HONDA/YAMAHA),and OEM quality engin parts for scootermotorcycle&ATV,UTV. We have always maintained a customer-centered philosophy and strive to exceed our customers' expectations and become a leading brand in the field of motorcycle parts and accessories. Whether you are an existing customer or a potential partner, we look forward to establishing a long-term relationship with you and working together to achieve the goal of mutual benefit and win-win situation.
Why Choose Us
Factory
With our excellent manufacturing technology and strict quality management system, our products enjoy a good reputation in the market. We focus on technological innovation and product development to continuously improve the quality and performance of our products to meet the needs and expectations of our customers.
Quality Assurance
We have always been committed to providing our customers with the assurance of high quality and efficiency to meet their needs and expectations for our products and services.
Produced Products
We mainly productsis full body fairing partsfor scooter motorcycle(mainly HONDA/YAMAHA),and OEM quality enginparts for scootermotorcycle &ATV,UTV.
Superior Service
We have always been committed to providing excellent service and offering all-round support and assistance to our customers.
Your crankshaft is an extremely robust moving part of your engine. It is placed low in the engine, close to the oil supply. The crankshaft function is to convert the up-and-down motion of the pistons into rotating motion that can be used to smoothly power your vehicle.As the pistons are pushed up and down in their cylinders by the process of combustion, they are linked to the crankshaft by connecting rods. The design of the crankshaft allows the lower end of the connecting rods to move in a circular direction, turning the crankshaft. This rotary motion of the crankshaft, along a linear axis, is directed into your motorcycle transmission and then to the driving wheels, moving the motorcycle forward or backward, depending on the driver needs.
Advantages of Motorcycle Crankshaft
Increased Power and Efficiency
Crankshaft improves power delivery, allowing your motorcycle to accelerate more effectively and reach higher speeds. The efficient transfer of energy from the engine to the wheels results in improved fuel efficiency, reducing the frequency of refueling stops during long rides.
Reduced Vibrations and Engine Stress
Vibrations caused by an imbalanced or worn-out crankshaft can lead to discomfort, fatigue, and even damage to other engine components. Investing in a quality crankshaft minimizes vibrations, ensuring a smoother and more enjoyable ride. It also reduces stress on engine components, extending their lifespan and mitigating the risk of failures.
Enhanced Reliability and Longevity
A reliable and durable crankshaft significantly reduces the likelihood of engine failures and breakdowns. By withstanding the demanding conditions of motorcycle operation, it contributes to the overall longevity and reliability of your bike. With a high-quality crankshaft, you can have peace of mind during your rides, knowing that your engine is performing optimally.
The crankshaft has a connecting rod attached to it at each of the four crankpins. Each rod has a piston rising and falling in its respective cylinder. That rising and falling produces a shaking force, which, to some extent, is counterbalanced by weights on the crankshaft.
The crankshaft is not just a simple zigzag line like my uncle drew for me when I was five. It has the added complication of these counterweights, which are there to reduce vibration and also the load on the main bearings.
Classic motorcycles of yesteryear had roller- and ball-bearing crankshafts. But roller and ball bearings don't last as long as people would like their motorcycles to last these days. This engine has plain journal bearings.
Smooth cylindrical journals are supported by skinny little shells—a pair of them, split at the centerline, just as the crankcase halves are split—which do the work of great big ball bearings. And they do a better job.
A thin film of oil between the smooth crankshaft journals and the bearing shells acts not only as a lubricant but a damper. So the crankshaft supported in five places by plain bearings and clamped between the upper and lower cases is actually very well supported.
Crankshafts are typically manufactured through a combination of forging and machining processes.
The first step is the forging process, where a billet of steel is heated and then pressed or hammered into the rough shape of the crankshaft. This forging process aligns the grain of the steel material to the shape of the crankshaft, improving its strength and durability.
After the initial forging, the crankshaft undergoes extensive machining operations. These include:
Turning - The forged crankshaft is mounted in a lathe and the main bearing journals and crank throws are turned to their final dimensions.
Grinding - The bearing surfaces are then precision ground to achieve the required surface finish and tolerances.
Drilling/Boring - Holes are drilled or bored through the crankshaft for oil passages.
Balancing
The crankshaft is dynamically balanced by removing small amounts of material from specific locations to ensure proper rotational balance.
Heat Treatment
Depending on the application, the crankshaft may undergo heat treatment processes like induction hardening or nitriding to increase surface hardness and wear resistance.
Final Inspection
The completed crankshaft is thoroughly inspected to ensure it meets all dimensional, hardness, and other quality specifications before being approved for use.
It is certainly possible for competent engine repairers/rebuilders to repair even severely damaged crankshafts because all crankshafts are designed with a "remanufacturing margin". In practice, this margin allows for the journals to be ground to up to a millimetre smaller than what their diameters were when the crankshaft was new.
However, whether (or not, as the case may be) any given crankshaft can be repaired largely depends on three factors, these factors being.
The degree of damage to the journals; in severe cases, grinding out the damage may result in the journals being below their minimum allowable diameters
Whether the crankshaft had been repaired before; if so, the journals may already be at their minimum allowable diameters
The steel alloy the crankshaft is made of; in many cases, especially on severely damaged older crankshafts, it is possible to reduce the bearing journals to their minimum allowable diameters and then to build them up again by a specialized welding process. Even if some damage remains, the welding process “seals” the damage, and subsequent grinding, polishing, and simple heat treatments can restore the journals to their original OEM specifications. However, with many modern steel alloys, the welding process destroys the crankshaft's hardness and wear resistance, and the specialized heat treatment required to restore the crankshaft's wear resistance to OEM-specified depths is so expensive and time-consuming that it is often more cost-effective to replace a damaged modern crankshaft than to attempt repairing it.
What Are the Types of Crankshafts
Ordinary crankshaft
A regular crankshaft is the most basic form of crankshaft, consisting of one or more connecting rods. Its main characteristics are simple structure and low manufacturing cost, but it is prone to vibration and imbalance during high-speed and high-power operation, which will have adverse effects on the stability and service life of the engine. Therefore, in high-performance engines, ordinary crankshafts have gradually been replaced by balanced crankshafts and cast crankshafts.
Balanced crankshaft
A balanced crankshaft is an improved crankshaft based on a regular crankshaft, mainly achieved by adding counterweights to balance the crankshaft and reduce vibration and imbalance. Balanced crankshafts are widely used in high-performance engines, which can improve engine performance and lifespan. However, the manufacturing of balanced crankshafts is more complex than ordinary crankshafts, and the cost also increases accordingly.
Casting crankshaft
Casting crankshaft is a crankshaft manufactured using casting technology, which has the advantages of low manufacturing cost and high production efficiency. Casting crankshafts can be divided into two types: pressure shell type and cast steel casting type. Cast crankshafts are widely used in low-power engines and large-scale production due to their low manufacturing cost. However, the strength and reliability of cast crankshafts are not as good as steel crankshafts and are not suitable for use in high-power, high-speed engines.
What Are the Symptoms of a Broken Motorcycle Crankshaft
Noise generation: Motorcycles produce significant noise during operation, which may be the most obvious sign of crankshaft damage, and the noise will vary with the operation of the engine.
Increased vibration: Damage to the crankshaft may cause an increase in engine vibration, which may make the driver feel uncomfortable while driving and may cause additional pressure on other components of the motorcycle.
Fuel consumption increase: If the crankshaft cannot effectively transfer power from the engine to the transmission system, the motorcycle's fuel consumption may increase because the engine needs to consume more fuel to generate enough power to overcome the resistance of the crankshaft.
Abnormal oil pressure: Damage to the crankshaft may affect the engine's oil pressure, and high or low oil pressure may cause damage to the engine.
Easy to pull cylinder: Damage to the crankshaft may cause severe interaction between the engine piston assembly and the working surface of the cylinder, resulting in excessive wear, burrs, scratches, scratches, cracks, or bite marks on the working surface.
Accelerated wear of parts: Damage to the crankshaft can lead to increasingly severe wear of related components, with a faster rate of wear.
The oil dispenser makes a clanging sound: When supplying oil, the machine will make a clanging sound, and the higher the throttle, the louder this sound will be.
These symptoms indicate that there may be a problem with the crankshaft of the motorcycle. If encountering these symptoms, the motorcycle should be promptly sent to a professional repair station for inspection and repair.
How to Distinguish the Motorcycle Pistons
There are generally grouping marks on the top of the piston, usually there are groups A, B, C and D, which are the size grouping marks on the piston skirt. In addition, there are several very fine grooves on the piston skirt, which are mainly used to store lubricating oil to enhance the lubrication function of the piston skirt. Due to the rough processing, it is impossible for defective pistons to undergo such a precise processing technology.
The wall of high-quality piston skirt is very thin, and its wall thickness is uniform. The size of one side of the piston skirt can be measured with a vernier caliper. If a digital display vernier caliper is used for measurement, the measurement result is more accurate because of its high precision. If the difference in wall thickness is more than 0.20mm, after the temperature of the piston rises, due to the different wall thickness of the skirt, the thermal deformation will be large and uneven, so that the size of the piston skirt will not reach its ideal perfect circle, which will not only easily cause leakage , and an abnormal knocking sound will be produced.
The cylindrical part from the bottom ring groove of the piston (referring to the oil ring groove) to the bottom surface of the piston is the piston skirt, which acts as a guide and bears side pressure when the piston reciprocates in the cylinder. The piston in non-working state is different from its working state under stress and heat. This is because the piston will be deformed to varying degrees when it is heated and stressed.
When the piston is in working condition, due to the force and heat, the dimensional deformation of the piston along the direction of the piston pin increases, while the deformation along the direction perpendicular to the piston pin is small. Therefore, in order to offset and adapt to its thermal deformation, ensure that the shape of the piston is cylindrical when it is working, so as to adapt to the inner wall of the cylinder and have a suitable fit clearance. In the non-working state, the size of the head of the piston viewed from the axis smaller, while the skirt is slightly larger;
The cross section of the piston (that is, the cylindrical section) should be oval when the major axis is perpendicular to the axis of the piston pin. The difference between the length of the cross-section of the piston produced by the regular manufacturer is 0.15 ~ 0.25mm. You can use a vernier caliper or a digital caliper to measure the dimensions of the above relevant positions, and compare them to distinguish the advantages and disadvantages.
Specific Causes of Motorcycle Piston Damage
Worn Diesel Piston Rings
If you’ve noticed white smoke coming from the tailpipe, low power for acceleration, overall power loss and also a significant drop in engine oil level these are key signs of worn diesel piston rings.
Your engine may experience these signs of piston ring damage as the seal between the piston and cylinder is no longer airtight, meaning the oil will leak into the crankcase and the firing chamber.
Worn diesel piston rings are a very common cause of piston damage, as the diesel rings circle around the piston act as a buffer between the combustion chamber and the crankcase, surrounding the crankshaft. Diesel rings are responsible for moving the heat away to the cylinder wall, whilst regulating the oil temperature.
Unfortunately, piston rings do wear out, and there is little you can do to prevent this. However, if you replace them routinely before they wear, it can play a great part in preventing damage to the engine.
Piston Skirt Damage
The main cause of damage on the piston skirt is caused by rubble coming through the air filtering system. This can cause the piston rock within the cylinder to wear the skirt down, making the skirt thinner and weaker, which can eventually result in the piston breaking.
Piston Snap
If your car is starting to make a rattling or knocking noises that remains by the time the car has warmed up, this could mean that there is a large gap between the piston and the cylinder wall.
Using a piston cleaning tool: This is a specialized tool that has a brush or scraper attachment that can be inserted through the spark plug hole to clean the top of the piston and cylinder walls. The tool allows you to reach and scrub the piston without disassembling the engine.
Valve cleaning solution: Some valve and fuel system cleaning products can be added to the fuel tank or injected directly into the cylinders. As the engine runs, the cleaning solution helps dissolve and remove carbon deposits from the pistons and cylinder walls.
Walnut shell blasting: This technique uses soft walnut shell media that is blasted into the cylinders through the intake or exhaust ports. The abrasive action helps clean the pistons and cylinder walls without requiring removal.
Decarb service: Some mechanics perform a "decarb" service where they use a specialized tool to scrape carbon deposits off the pistons and cylinder walls through the spark plug hole. This is more involved than the piston cleaning tool but can be effective.