{"id":288,"date":"2018-08-14T12:30:16","date_gmt":"2018-08-14T12:30:16","guid":{"rendered":"http:\/\/commons.princeton.edu\/63-tiger-cub\/?page_id=288"},"modified":"2018-08-14T12:31:11","modified_gmt":"2018-08-14T12:31:11","slug":"cylinder","status":"publish","type":"page","link":"https:\/\/commons.princeton.edu\/63-tiger-cub\/cylinder\/","title":{"rendered":"Cylinder"},"content":{"rendered":"<div class=\"picture-component\">\n<div class=\"body\">\n<div>The lower section of the top end of the engine consists of the<\/div>\n<ul>\n<li>Cylinder<\/li>\n<li>Crankshaft<\/li>\n<li>Piston and rings<\/li>\n<li>Cam<\/li>\n<li>Lifters<\/li>\n<li>Push-rod assembly.<\/li>\n<\/ul>\n<p>The head bolts onto the top of the cylinder, and the two pushrods connect the motion of the cam to the movement of the valves.<\/p>\n<\/div>\n<\/div>\n<h3 class=\"component-spacing\">Exploded Diagram of Cylinder and Pushrod Assembly<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-289\" src=\"http:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/top-end-exploded.png\" alt=\"\" width=\"839\" height=\"883\" srcset=\"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/top-end-exploded.png 839w, https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/top-end-exploded-285x300.png 285w, https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/top-end-exploded-768x808.png 768w\" sizes=\"auto, (max-width: 839px) 85vw, 839px\" \/><\/p>\n<figure id=\"attachment_290\" aria-describedby=\"caption-attachment-290\" style=\"width: 842px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-290\" src=\"http:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/presentation.jpg\" alt=\"\" width=\"842\" height=\"637\" srcset=\"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/presentation.jpg 727w, https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/presentation-300x227.jpg 300w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><figcaption id=\"caption-attachment-290\" class=\"wp-caption-text\">The components marked here are all part of the cylinder and pushrod assembly. These are the original parts from the motorcycle as we received it. No restoration has been done and the parts have only been lightly cleaned.<\/figcaption><\/figure>\n<hr \/>\n<div class=\"picture-component\">\n<h3>The Beginning of the Restoration<\/h3>\n<figure id=\"attachment_291\" aria-describedby=\"caption-attachment-291\" style=\"width: 420px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-291\" src=\"http:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/custom-jig.jpg\" alt=\"\" width=\"420\" height=\"560\" srcset=\"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/custom-jig.jpg 420w, https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/custom-jig-225x300.jpg 225w\" sizes=\"auto, (max-width: 420px) 85vw, 420px\" \/><figcaption id=\"caption-attachment-291\" class=\"wp-caption-text\">Custom jig for reboring on a lathe<\/figcaption><\/figure>\n<h3>\u00a0The cylinder needed to be\u00a0<strong>rebored<\/strong><\/h3>\n<p>It was wrong from the previous boring job, bored off center and tapered as well.\u00a0 We decided to make it 0.060 inches over its original diameter, and ordered a new piston to fit that new size.\u00a0 The bore of a cylinder is a measure of its inside diameter.\u00a0 We bored the cylinder on the lathe, bolting it onto a custom jig using the four holes for the head bolts.\u00a0\u00a0<strong>The idea here is to take only a few thousandths off at a time, and advance the cutter slowly to create a uniform surface.<\/strong><\/p>\n<div id='gallery-1' class='gallery galleryid-288 gallery-columns-2 gallery-size-medium'><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/phplswdS1PM.jpg'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"225\" src=\"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/phplswdS1PM-300x225.jpg\" class=\"attachment-medium size-medium\" alt=\"\" srcset=\"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/phplswdS1PM-300x225.jpg 300w, https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/phplswdS1PM.jpg 600w\" sizes=\"auto, (max-width: 300px) 85vw, 300px\" \/><\/a>\n\t\t\t<\/div><\/figure><figure class='gallery-item'>\n\t\t\t<div class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/phpdABM9kPM.jpg'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"225\" src=\"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/phpdABM9kPM-300x225.jpg\" class=\"attachment-medium size-medium\" alt=\"\" srcset=\"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/phpdABM9kPM-300x225.jpg 300w, https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/phpdABM9kPM.jpg 600w\" sizes=\"auto, (max-width: 300px) 85vw, 300px\" \/><\/a>\n\t\t\t<\/div><\/figure>\n\t\t<\/div>\n\n<p>The desired result is to have the bore diameter just slightly more than the piston diameter, within a few thousandths, allowing the piston rings to squeeze out against the inside of the cylinder and form a seal.\u00a0 Once the correct bore diameter is established, the cylinder wall has to be honed, which removes scratches and grooves made from the cutting tool.\u00a0\u00a0<strong>The honing tool is also used to create tiny vertical grooves in the cylinder wall, allowing oil to move vertically in the cylinder.<\/strong><\/p>\n<p>If the grooves from the boring were left in oil would only move in a spiral fashion, and the cylinder would be ineffectively lubricated.\u00a0 The piston rings have gaps in them for two reasons.<\/p>\n<ul>\n<li>The first is to allow room for expansion, so the rings can expand when they heat up and not bend<\/li>\n<li>The second is to allow oil to move throughout the cylinder.\u00a0 The tiny gap allows a miniscule amount of oil through to lubricate the walls. Too large of a gap will decrease compression, while too small a gap can cause the rings to bend or the engine to overheat due to lack of lubrication.<\/li>\n<\/ul>\n<hr \/>\n<div class=\"picture-component\">\n<h3>Piston and Rings<\/h3>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-294 aligncenter\" src=\"http:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/4StrokeEngine_Ortho_3D_Small.gif\" alt=\"\" width=\"225\" height=\"300\" \/><\/p>\n<p>There are\u00a0<strong>three<\/strong>\u00a0rings on most pistons. The main functions of these rings are &#8211;<\/p>\n<ol>\n<li>To seal the combustion chamber<\/li>\n<li>Regulate oil inside the cylinder<\/li>\n<li>Transfer heat from the piston to the cylinder to the cooling fins on the outside of the cylinder.<\/li>\n<\/ol>\n<p>The two rings closer to the top of the piston are intended to seal against compression loss, while the bottom ring controls the movement of oil inside the cylinder.\u00a0 This one allows oil to move around the outside of the ring, leaving a lubricating layer of oil on the walls of the cylinder.<\/p>\n<p>The piston rings have gaps in them for two reasons.<\/p>\n<ol>\n<li>The first is to allow room for expansion, so the rings can expand when they heat up and not bend<\/li>\n<li>The second is to allow oil to move throughout the cylinder.<\/li>\n<\/ol>\n<p>The tiny gap allows a miniscule amount of<a name=\"_GoBack\"><\/a>\u00a0oil through to lubricate the walls.\u00a0 Too large of a gap will decrease compression, while too small a gap can cause the rings to bend or the engine to overheat due to lack of lubrication.\u00a0 The piston is domed, which decreases the size of the combustion chamber, increasing what is called the \u201ccompression ratio\u201d of the engine. \u00a0 This number is the ratio of the pressure in the cylinder above the piston at the top of its travel (smallest volume) divided by the pressure when the piston is at the bottom of its travel (largest volume).<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-295\" src=\"http:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/piston.jpg\" alt=\"\" width=\"851\" height=\"405\" srcset=\"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/piston.jpg 561w, https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-content\/uploads\/sites\/74\/2018\/08\/piston-300x143.jpg 300w\" sizes=\"auto, (max-width: 709px) 85vw, (max-width: 909px) 67vw, (max-width: 1362px) 62vw, 840px\" \/><\/p>\n<p>The piston we have creates a\u00a0<strong>higher compression ratio<\/strong>\u00a0than the stock piston.\u00a0 A higher compression engine is a higher performance engine, because it has a higher thermal efficiency. The air-fuel mixture is more concentrated, and the adiabatic heat of compression increases the temperature of the mixture. \u00a0 These two factors result in a\u00a0<strong>better fuel-air mixture, which increases the power of the engine.<\/strong><\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>The lower section of the top end of the engine consists of the Cylinder Crankshaft Piston and rings Cam Lifters Push-rod assembly. The head bolts onto the top of the cylinder, and the two pushrods connect the motion of the cam to the movement of the valves. Exploded Diagram of Cylinder and Pushrod Assembly The &hellip; <a href=\"https:\/\/commons.princeton.edu\/63-tiger-cub\/cylinder\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Cylinder&#8221;<\/span><\/a><\/p>\n","protected":false},"author":6,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-288","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/pages\/288","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/comments?post=288"}],"version-history":[{"count":1,"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/pages\/288\/revisions"}],"predecessor-version":[{"id":296,"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/pages\/288\/revisions\/296"}],"wp:attachment":[{"href":"https:\/\/commons.princeton.edu\/63-tiger-cub\/wp-json\/wp\/v2\/media?parent=288"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}