Motorcycle Engine Information and Troubleshooting GuideMotorcycle engines will fail and knowing how they work and how to troubleshoot them is very important. If you think about being stuck on the side of the road with no help you will wish that you knew how the motorcycle engine works in addition to the accessories that also might fail. Troubleshooting a motorcycle should be simple and should be approached in an organized fashion.
Troubleshooting basics: Motorcycle troubleshooting can be frustrating. Keep it simple and follow the following tips. - Quickly look over the motorcycle and look for obvious problems or something that sticks out as a potential problem. Make sure all electrical connections are tight. Make sure you have fuel in the tank. Make sure you have power. Make sure nothing is hanging off that shouldn't be. - Think about the problem itself. Try to link it to parts and accessories that simply make sense. It doesn't make sense that you look at tail light connections if you have a problem starting the motorcycle. - Once you pin point the root cause of the problem or an idea of what can be causing the problem you are experiancing take the troubleshooting to the next level. Take out your tools and testers (hopefully you have some with you) and try to proove the cause of the problem. - Next step is logical, simply go ahead and fix it or contact roadside assitance if the problem cannot be fixed in place. Ok, Now that we have the basic troubleshooting steps down let's talk about how engines work. Two-Stroke Motorcycle Engine: The two-stroke motorcycle engine is the simplest of all with only 1 piston. Let's look at the major stages of each cycle. We'll talk about the exhaust and intake ports and the down and up strokes. When the piston is all the way down the following occurs: transfer ports are open providing new fuel mixture from the crankase and the burned exhaust gases are pushed out through the exhaust port. When the piston begins to travel up or rising with transfer and exhaust ports closed the new mixture begins to get compressed and getting ready for firing by the spark plug. When the piston is still rising the intake port opens and begins to fill the crankase with new fuel mixture from carburator (the crankase contains the flywheels). Remember both transfer and exhaust ports are still closed mixture from previous cycle is being compressed. When the piston reaches it's peak or top dead center the spark plug ignites teh mixture the piston begins to travel back down, the inlet port is closed. Back to the beginnig of the cycle. Each ignition occurs every 2 strokes (up and down). This is why the name of this motorcycle engine. Newer designs have 5 or 7 ports for much more efficient operations reducting fuel consumption.
Rotary Two-Stroke Motorcycle Engine: Same in principle as the old fashion two-stroke engine except it's build differently and has some benefits from the design. This engines advantage is that intake timing is not dependent on the transfer and exhaust ports because in this design the intake port is on the side of the crankase and is dependent on position and the duraion of the valve cutaway. Pushrod Four-Stroke Motorcycle Engine: A power cycle in a pushrod four-stroke engine requires 4 strokes of the piston. On the intake stroke the intake valve opens and fuel mixture flows into the cylinder. When the piston starts to move to the top or upwards both valves are closed and compression occurs with fuel and air. As the result of the firing the force created pushes the piston down and creates the power stroke. During the downward travel the exhaust valve opens the remains of the exhaust from previous charge is pushed out. Now again when the piston is at it's top position the intake valve opens, the exaust flow starts the intake flow and the exhaust valve closes. Overhead Camshaft Four-Stroke Motorcycle Engine: Engines with cams on top of it's valves are called overhead camshaft engines. Cam drives can be driven one of the following: chain or dual chain, spur gears, shaft and bevel gear, and reciprocating rods. The most widely used because of cost, sound and other reasons is the chain driven over head cams. Single Rocker arms are used to move the valves in overhead cam engines. In dual overhead engines usually will have cams located directly above the valve stems. Tip: Valve adjustment is more difficult with dual overhead cam solution. There is one advantage in using an overhead design. It weights less and have less valve problems when compared to pushrod engines. The drawback however is that the overhead design engine is taller which makes the center of balance higher and creates difficulty in handling and balance. Motorcycle weight and engine size contributes to engine maintenance. Ok, that was long but hopefully you now get a basic understanding of how a motorcycle engine works. When you notice one of the following situations you probably have an engine problem - look into it ASAP!!!
To read about motorcycle sizes and engine performance click here.
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