2013 MOTORCYCLE PISTON

Piston

well at this time of my discussion about attempting to discuss the so-called pistons. may be quite lengthy discussion with friends, and I hope you want to read it until the end .. ok let's discuss 

The piston has a cylindrical shape . Working and moving in translation ( movement back and forth ) in the cylinder . piston is precision sliding axis mounted in a cylinder . with purpose , either to change the volume of the tube, push the fluid in cylinder , opening and closing the flow path or a combination of all of it . piston encouraged as a result of the expansion pressure as a result combustion . Piston always receives temperature and pressure high , moving at high speed and continuously . movement piston can move 2400 times or more every minute . So every second piston moves 40 times or more in the cylinder . temperature received by different piston and also different from the effect of heat surface to the other surface . What really happens is expansion of hot air so that the pressure -containing energy very large . The piston moves from TDC to BDC as motion straight . Furthermore , the piston back to TDC dispose of used gas . Up and down movement of the piston is going very fast service of process a motor comprising the steps of charging , compression , work steps and disposal of used gas .

Figure 1 . PISTONS

The top of the piston was originally made ​​flat . However , for improve the efficiency of the motor , especially on two-cycle engine , convex surface of the piston is made symmetrical and convex but notsymmetrical . Convex shape of the surface point to complete flushing of the fuel air mixture . simultaneously , the top surface of the piston is also designed to expedite disposal combustion gases .

Figure 2. Types of Piston Heads

 But sufficient to meet the requirements:
1. Resistant to high temperatures.
2. Able to withstand the pressure acting on it.
3. Easy to dissipate heat in the surrounding
4. Lightweight and strong.
The piston consists of piston, piston ring and piston rods. each piston fitted more than one piston ring. The ring is attached loose in the ring groove. piston ring divided into two kinds, namely:
1. Ring Compression, number one, or two, and for motors The larger of the two. Its function is to close between the piston with the cylinder wall so it does not happen leakage at the time of compression.
2. Oil ring, mounted on the bottom row and shape such that it can easily bring oil lubricant to lubricate the cylinder walls  Two stroke engine piston rings slightly different piston rings with four-stroke engine. Two stroke engine piston rings are usually only 2 fruit, which both serves as a compression ring. mounting ring piston can be done without tools but must be careful because the ring easily broken piston. The damage that occurs in the piston ring can result in two steps:
1. Inner cylinder walls wear out quickly
2. The machine is not stationary
3. Sounds lame machine
4. Engine power less
5. Difficult machine is turned on
6. Compression machine weak

 

Figure 3. piston arrangement

In the two- step installation of the motor piston rings must be precisely the spi contained in the piston ring groove . Spi on the piston ring must entered the indentation in the piston groove . Spi ( pen ) the function to lock the piston rings that are not easily shifted to the left or to Right . Unlike the four stroke engine piston rings where the ring not locked with spi . Shifting four-stroke engine piston ringsnot so dangerous but the two stroke engine can ring concerns in the rinse holes or holes so that the ring can waste broken . Before the piston fitted into the cylinder , piston rings must installed first. Installation of piston rings good and true is to pay attention to the signs that exist . piston ring The first should be installed at the very top . Usually on the surface existing piston ring number. Words and figures on the surface piston rings must be in the top or can be read from above . The other thingto note is the placement of piston ring connection . Piston ring connections ( gap ) should not be aligned , meaning that if there are three then the distance between the piston ring piston ring must be the same connection that is 1200. if there are two distances between the piston ring connections is 1800 . in  

Besides piston ring connection should not be in line with the pen piston . All this to prevent compression leaks . for motorcycle piston ring mounting two steps , the spi piston rings must be entered in the indentation in the piston groove . Piston rings mounted on the gas above the piston to insulate piston compression and expansion process that can take place with as well as possible , because when the cylinder space above the piston should really be closed, the piston rings also helpcool the pistons , by means of channeling some of the heat the piston to the cylinder wall .The function of piston rings is to maintain density between the piston with the cylinder wall so that no gas leaks from combustion chamber into the crankcase . Therefore, the piston rings must to have a strong spring in which an emphasis on the wall cylinder .Piston together with the piston rings to function as the following :1 . Sucking and compressing the fresh charge in the cylinder2 . Changing gas power ( for expansion ) into mechanical effort3 . Partition relationships and the gas above and below the pistonIn mounting the piston we recognize the existence of the pen piston . Pen piston serves to bind the piston to the piston rod . In addition , it also serves as a piston pen transfer of power piston to the piston rod back and forth so that the motion of the piston can be changed into a rotating motion on the crankshaft . Although mild forms  but the piston pen made ​​of high-grade alloy steel in order to withstand the enormous burden . Another part of the piston that the piston rod is often called the piston , it serves to connect the piston to the shaft crank . So the forward movement of the piston rod of the piston to the crankshaft . Where the back and forth motion of the piston in the cylinder chamber forwarded by motion of the piston rod into rotation ( rotary ) on the crankshaft . this means that if the piston moves up and down , the crankshaft rotates . Upper end where there is a pen called a piston end small end of the piston rod and the lower part is called the big end . in small end of the piston rods were equipped with wear pads bullet and fitted again with a metallic bronze or bush boaring ( his name in the store in terms of sales of automotive components motor ) . The tip of the magnitude associated with balancer shaft crank through the king pin and ball bearings . In general, shaft length about the size of two time step of motion of the piston . Piston rod is made of steel or iron materials Castings .Piston on a motorcycle can be divided into two kinds of motorcycle piston for four steps and pistons for motorcycles two steps . In general, the two forms are not the same piston . Motorcycle piston has four steps for oil ring groove so the number of three or more grooves . In the piston ring groove four stroke motorcycles there is no indentation . For more details we see image

 

Figure 4.

Components of the four-stroke engine, DOHC piston
engine. (E) Exhaust camshaft, (I) Intake camshaft, (S) spark plug, (V)
Valves (valve), (P) Piston, (R) coneccting rod, (C) Crankshaft,
(W) sheath flow of water for cooling.

 Piston for motorcycle usually do not have a two- step groove for the oil ring groove on the piston so that the number of motorcycle two usually only two steps . on the side of the piston in the plot are indentations to ensure that the piston rings do not rotate shifts after installed . Two step hollow piston on its side . The function of the hole The new gas to flow into the crank chamber .Piston is used for different motorcycles to those used for four-wheeled vehicles . piston for motorcycle has a specific pre-determined size , size piston called STD ( standard ) is a measure of goods from factory the author , is a measure that is still original and has never been changes . So the views of its size there are two sizes namely the size of a standard piston and piston size over size . piston standard used in the standard cylinder engine while the piston over -size cylinders that have been used in over size . What is meant by expansion over size is the diameter of the cylinder . expanded diameter The cylinder because the cylinder wall wear . The sizes of piston for the purposes of motorcycles are:- + STD = Piston pristine / new- Size + 0.25 mm = Piston over size 25- Size 0.25 mm- Size 0.50 mm- Size 0.75 mm- Size of 1.0 mmInstallation of the piston into the cylinder must consider the signs are there . There is usually a sign of arrows . The arrows should face the exhaust ( muffler ) , if installation of inverted piston then the result is fatal that the wear that occurs between the cylinder wall with the piston being very large . Another sign to watch for is if we want to replace the piston , if the piston head surface writing numbers particular , the figure shows that the diameter of the cylinder bike motor has been experiencing over size . Piston replacement should be in accordance with or equal to the size of the cylinder piston replaced . In her treatment needs in the service piston , stage it treatment is :1 . The piston is released from its holder2 . Piston soak in cleaning fluid together with piston rod , then pat dry .3 . Clean dirt charcoal on the piston ring groove .4 . Observe the piston ring groove wear possibilities . Wear of the largest usually occurs in the compression ring grooves .5 . Check the piston ring groove freedom with feeler gauge . ring groove piston can be repaired by cutting grooves and larger installing a steel ring at the top.
6. Check whether there is a rift in the piston. cracks piston no matter how small should be replaced.
7. Remove the piston pen. Before the piston removable pen mark so easy to put back as original position.
8. When the piston pen-type floaters, off the locking ring so that the pen easily removed. Be careful when removing the ring, not to damaged. Generally engines today use a pen that can pressed to move the piston and the piston rod.
9. Upon inspection of the finished piston pen reinstall as before. Because freedom of the pen against the piston very small, ie between 0.005 to 0.0127 mm for piston installation of aluminum it is necessary to carefully. freedom on the piston rod bearings that bit wide large which is about 0.0127 mm.

 Huff....discussion of the display is not friend .. please leave suggestions and criticisms ^_-