Honda Scooter 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.
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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.
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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.
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We have always been committed to providing excellent service and offering all-round support and assistance to our customers.
The crankshaft of an engine, is the component that converts the up and down motion (reciprocating motion) created by the pistons, into rotary motion. The rotary motion ultimately turns the back wheel with the aid of a chain, propelling the motorcycle forwards. The crankshaft of an engine, is the component that converts the up and down motion (reciprocating motion) created by the pistons, into rotary motion. The rotary motion ultimately turns the back wheel with the aid of a chain, propelling the motorcycle forwards.
High strength material: Made of high-strength alloy steel or aluminum alloy, capable of withstanding high-strength working loads.
High precision machining: With high machining accuracy and smooth operation, it can improve engine efficiency.
Strong balance: With a balance block, it can balance the rotational inertia force of the crankshaft, improve the handling and stability of the vehicle.
Good adaptability: Strong compatibility with engine cylinders, transmission and other components, ensuring the overall performance and stability of the vehicle.
Working Principle of Crankshaft
The crankshaft is one of the important components in the engine. Its main function is to withstand the force transmitted by the connecting rod and convert it into torque output through the crankshaft to drive other accessories on the engine. The working principle of the crankshaft can be summarized as follows:
Conversion of force
The crankshaft converts the gas pressure transmitted from the piston connecting rod into torque, which serves as power to output work, drive other working mechanisms, and drive the auxiliary equipment of the internal combustion engine to work.
Structural composition
The crankshaft is generally composed of a front end shaft (free end), a main journal, a connecting rod journal (crank pin), a crank arm, a counterweight, and a rear end flange (power output). These components work together to ensure that the crankshaft can effectively convert and transmit power.
Lubrication system
The lubrication of the crankshaft mainly refers to the lubrication of the connecting rod big end bearing shell and the crankshaft connecting rod neck, as well as the lubrication of the two fixed points. The oil lubricates the working surfaces of the main and connecting rod journals to ensure smooth operation of the crankshaft.
Force analysis
The crankshaft is subjected to the combined action of centrifugal force from rotating mass, periodic gas inertia force, and reciprocating inertia force, which causes the crankshaft to withstand bending and torsional loads. This requires the crankshaft to have sufficient strength and stiffness, as well as good wear resistance and balance.
Knocking noises from the engine
Knocking noises coming from the engine is one of the common symptoms of a bad crankshaft . Drivers usually refer to this as a rod knock which sounds like a consistent hammering that increases as the RPM does. This can occur when the crankshaft has worn out that causes excess clearances. Rod knocks can happen when the rod big ends hit against the crankshaft at the top and the bottom of the piston stroke.
Low oil pressure
A low or reduced oil pressure is an early symptom of a bad crankshaft. You will usually notice it when you first start your car. Sometimes, a worn can also set off the check engine light to illuminate intermittently depending on the severity of the problem.
Worn can lead to having excess clearances between the that can trigger an oil pressure leak. It usually occurs when your vehicle is at low RPM where the pump is spinning the slowest. Although low oil pressure can be caused by a lot of issues from other car components, it is also one of the symptoms of a bad crankshaft.
Metal shaving found in the oil
If you check your oil using a dipstick and you notice metal, silvery shavings or aluminum dust in it, it is an indication that your have worn out. You will know if what you found in the oil is caused by a worn if the aluminum shavings look like dust or is powder-fine. If you see splinters or strings of aluminum stuck in the dipstick, it means that it is not caused by normal wear and tear but from overheating or running out of oil. This could mean that your have already failed or are starting to fail.
Copper sheen found in the oil
A lot of crankshaft have three layers that include an aluminum outer layer, a copper layer in the middle, and a steel backing plate. These kinds of use copper that is known to be a softer but smoother metal compared to aluminum. This is done to give an extra protective layer before the wears down to the steel or before it completely fails.
Crankshaft noise
This problem is caused by low oil pressure that can potentially damage the surfaces and the crankshaft itself. The crankshaft noise can be heard as a rumbling or thumping sound that seems to be coming somewhere deep in the engine when you are accelerating.
What Are the Materials of the Crankshaft
Steel crankshaft
Steel is a common material for crankshafts, which has high strength, toughness, and wear resistance. Steel crankshafts are mainly divided into three types: carbon steel, alloy steel, and stainless steel. Carbon steel crankshafts have lower costs, but lower hardness and strength, and are generally used in low-power and low-speed engines; Alloy steel crankshafts have higher hardness and strength, better durability, and are suitable for high-power and high-speed engines; Stainless steel crankshafts have good corrosion resistance, but they are relatively expensive and are generally suitable for high-end sedans or professional racing engines.
Cast iron crankshaft
Cast iron crankshafts have lower costs compared to steel crankshafts, are lightweight, have good rigidity, and have less damping, but their hardness and strength are not as good as steel crankshafts. Cast iron crankshafts are mainly used for low-power engines, such as small motorcycles, agricultural engines, etc.
Aluminum alloy crankshaft
Aluminum alloy crankshafts are lighter in weight and have better heat dissipation performance, which can effectively reduce engine weight and improve engine thermal efficiency. However, due to the lower hardness and strength of aluminum compared to steel, it can carry lower power and speed, and is generally used for small engines or motorcycle engines.
How Do You Fix a Bad Crankshaft
The crankshaft has been damaged, but nothing else inside the engine is affected: The crankshaft may be repairable, or it may need a replacement. Remanufactured crankshafts are available, which are a cost-saving solution, compared to buying a new crankshaft. If your motorcycle is very old with high mileage but otherwise runs fine, you might be able to find a cheap used crankshaft in a junkyard, to save money and keep your motorcycle running a bit longer. The crankshaft bearings should also be thoroughly checked, to confirm that they are still in good condition. Bad bearings will quickly destroy your new crankshaft.
The crankshaft and its bearings have been damaged: This type of damage is more extensive, because the bearings must also be repaired. The forces that caused the crankshaft damage have also damaged the bearings, causing excess wear, or making their formerly round surfaces into an irregular shape. A new or remanufactured crankshaft and bearings may solve the problem, but if the damage is too extensive, you might consider getting a remanufactured replacement engine (if the motorcycle is fairly new). If your motorcycle is old and worn out, it may be time to say goodbye and send it to the junkyard.
The crankshaft, the bearings, and the top end of the engine have been damaged: This is the most catastrophic type of crankshaft-related damage. In addition to damage to the crankshaft and its bearings, the connecting rods and the pistons attached to the crankshaft have also been damaged. And if the pistons hit the tops of the cylinders, they can cause serious damage to the intake and exhaust valves. Now you have a huge and expensive mess that involves repairs to your entire engine. A replacement engine may be your best option if the motorcycle has some value left in it.
Use the recommended engine oil weight and change it at the manufacturer's recommended intervals. Proper lubrication is crucial for reducing friction and wear on the rings.
Ensure the engine is not burning oil excessively. Oil consumption can lead to carbon buildup on the rings, causing them to stick and wear prematurely.
Maintain proper coolant levels and change the coolant as recommended. Overheating can cause the rings to expand and stick, leading to accelerated wear.
Avoid prolonged idling or running the engine at low speeds. This can allow oil to accumulate on the cylinder walls, reducing the lubrication needed for the rings.
Replace the piston rings according to the manufacturer's replacement interval, even if they don't appear to be worn. Worn rings will allow increased blow-by and oil consumption.
Check for and address any issues that may be causing increased ring tension, such as misaligned pistons or a warped engine block or cylinder head.
Use a piston ring compressor tool when reinstalling pistons to ensure the rings are not damaged during installation.
The piston, a key component in internal combustion engines, transforms combustion energy into mechanical work, delivering it through the connecting rod to the crankshaft as rotational force.
Operating in extreme conditions of high pressure, inertial forces, and temperatures, pistons move with a reciprocating linear motion inside the cylinder.
Pistons feature a roughly conical shape and comprise the following elements:
Crown: The upper part of the piston, which also serves as the movable lower part of the combustion chamber.
Head: The top side part of the piston (above the wrist pin), where grooves housing the piston rings, also known as seal rings, and the oil scraper ring (only for 4-stroke engines) are located.
Skirt: The side part below the head, guiding the piston's movement and transferring the lateral thrust due to the connecting rod's inclination to the cylinder wall.
Wrist pin: The pin that connects to the connecting rod, inserted with minimal clearance.
Around the piston are the piston rings: These play a crucial role as they help cool the piston, ensure combustion chamber pressure retention, prevent oil from the crankcase from mixing with the fuel or combustion gases in 4-stroke engines, and above all, provide adequate lubrication between the cylinder walls and the piston.
How to Change a Motorcycle Piston
Remove the timing chain slider
Before removing the barrel, you'll need to pull out the plastic timing chain slider. This almost always sits at the front of the engine, and can simply be pulled out. The slider has two lugs formed into the plastic that nestle into a groove on the top of the barrel, thus ensuring the slider stays put. When re-installing the slider later, make sure that the tip of the slider and the lugs are properly aligned.
Removing the barrel
With the timing chain slider removed, the only thing getting in the way of the barrel's removal is the timing chain. A long piece of tie wire twisted around the timing chain allows you to simply let the chain drop down into the engine cases and be easily retrieved later. Then pry the barrel from the cases and pull the barrel over the piston. You may need to rotate the engine (via the crank nut) to get the piston lower in its stroke if you have limited removal room in the frame. Clean the gasket surface in the same way that you did with the head.
Removing the piston
The final step in the disassembly process is removing the piston. This is an easy step, but can lead to a world of pain if you lose a circlip down into the engine cases. To avoid this, grab a clean rag and wrap it tightly around the conrod then fanning out over the gasket surfaces, so that anything dropped will land on the rag. Use a pair of circlip pliers to remove the circlip out from one side of the piston and the end of the gudgeon pin. Then push the gudgeon pin out to remove the piston from the conrod.
Oil up the new rings
After you've inspected the piston, rings and bore and set up the new rings on the piston you're going to use (see the sidebars on those steps), pour some heavy oil on the rings and distribute it around the piston. This provides some lubrication for when you first start up the motorcycle after the rebuild and prevents any initial scouring.
Install the piston into the barrel
When reinstalling the piston and barrel on the motorcycle, it is possible to install the piston first then place the barrel over the top, however this can be a fiddly process. The best method is to partly install the piston into the barrel on the workbench, where you can easily pinch the rings together and ensure they're lined up correctly. While you're there, install a circlip on one side of the piston to make life easier when you're putting the gudgeon pin through the conrod in the next step.
Reinstall the new piston & barrel
Before you go putting the piston on, make sure the gasket surface on the cases is clean and that you've laid a base gasket out on the surface and over the conrod.Then grab the barrel with the piston already in place. Slip the gudgeon pin through the piston and conrod, then insert the second circlip, making sure it's firmly in its slot. An important trick here is to ensure that the eyes of the circlip are facing either directly up or down in the slot, in line with the direction of travel of the piston. If the circlip gap is placed at three or nine o'clock (when viewed from the side), the g-force the circlip is subject to when the piston changes direction at the end of the stroke could cause the weight of the circlip to push against its own spring tension and come out of place.
Reinstall the head
With the barrel secured and the timing chain slider reinstalled, place the dowels into the top of the barrel to align the head. With the gasket surface clean, seat the new gasket into position, then place the head onto the cylinder. Using the wire connected to the timing chain, pull the chain up through the head and tie it up to the frame of the motorcycle. Push the head down onto the dowels and ensure the gasket is seated well, then check that the timing chain slider remains seated.
Adjust the head tension
With the head in place, bolt the head and barrel to the cases. Of all the bolts on your motorcycle where it is important to get the correct tension, the head bolts are probably the most crucial, so use a torque wrench. If you're re-using the head bolts, they have already been stretched once, so use plenty of caution and try to ‘feel' the bolt stretch. To remove any unwanted friction, use a dab of copper anti-seize grease on the thread and under the bolt head.
Reinstall
With the head and barrel back in place and correctly torqued, reinstall the exhaust, carby or throttle body, and radiator hoses. Then follow the steps in the valve adjustment story to put the valve train back together and reinstall the timing chain, and then fill the cooling system with fluid. Put the top engine mounts back on, reinstall the throttle cables and put the tank and plastics back together, and you should be good to go.