ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Motorcycle Oil Delivery System

Updated on October 5, 2009
Custom Chopper
Custom Chopper

Oil Delivery System Overview

The oil delivery system of any motorcycle engine is arguably the most critical engine system. The primary purpose of the oil delivery system is to provide lubrication to the moving parts of an engine. When moving parts come in contact with one another, they generate heat. The heat is a result of friction. Oil reduces this affect, and thus reduces friction and heat. Without lubrication friction and heat would cause the parts to fail. Oil also acts as a cleaning agent, suspending dirt and debris (metal shavings, sludge, etc.) until the oil passes through the oil filter.

Oil is typically delivered through dedicated lines, passages cast in the motorcycle engine block, and in some cases, pushrods and rockers. It is circulated through the system by a pump. The oil is returned to the pump through passages, lines and cylinder heads. The oil will be filtered before it reaches the pump.

Custom Oil Bag
Custom Oil Bag

Components of the Oil Delivery System

Most modern V-twin systems are comprised of several components. Each of these components will be described in greater in the following sections.

· The oil tank, also known as the oil bag, acts as a reservoir for the oil in the system. It is also used to help dissipate heat from the oil as it circulates.

· An oil pump is used to circulate the oil throughout the system.

· The oil filter removes particles suspended in the oil, thereby cleaning it before it is re-circulated.

· Oil lines and passages are used to transport the oil throughout the system, much the same way arteries and veins work within the human body.

· Oil is used as a lubricant, cleanser, cooler and seal when the engine is under power.

· Oil coolers, not standard on most models, can also be added to a system to dissipate heat, therefore increasing the effectiveness of the system.

Modern motorcycles use some of the most advanced systems in the marketplace. A good reason for this is the simple fact that most are still air cooled. That means that the only cooling the engine receives is from the surface area of the cylinder heads and the circulating oil. If the oil delivery system fails, it won’t take long for the engine to follow suit.

V-twin Oil Pump
V-twin Oil Pump

The Tale of Two Systems

 Most modern V-twins use a dry sump oil delivery system. The dry sump system uses a pump and a remote oil tank (oil bag) for storage. This differs from a wet sump system (described in the following paragraphs) where parts of the engine are actually submerged in the oil. Oil from the tank is introduced to a pump through a metering system that is timed to the movement of the camshaft and crankshaft. The metering system typically consists of a vent gear or reed valve.

Dry Sump systems use a two-sided pump. This type of pump is common in American motorcycle V-twins. Each side of the pump performs a specific task. The “feed” side creates the pressure to distribute the oil to all areas of the system. The “scavenge” side returns oil to the oil bag, after it has passed through the filter.

A Wet sump system is the older method of oil delivery. This system uses a reservoir mounted on the underside of the engine, called a crankcase. The system is simpler than the dry sump, requiring fewer moving parts and no exterior oil lines. Wet sump systems use a one-sided pump to distribute the oil to the block and cylinder heads. Additionally, some moving parts of the engine are partially submerged in the oil and actually use their own movement to splash oil on surrounding parts. As the oil is returned to the crankcase it is filtered through a screen, and in some cases an additional filter is added.

One distinct disadvantage to the wet sump system is called windage. When moving parts are submerged in oil it takes more force to move them and sustain that movement. It is easily compared to the difference between running on a sidewalk and running in a pool. Displacing the oil adds resistance and in return reduces the efficiency of the motor. Some other disadvantages, as compared to dry sump oil delivery systems, are the size and location of the crankcase. Since the crankcase must house the oil, it must be larger in size; it must also be mounted below the lowest point of the engine. The engine, therefore, must be mounted higher in the frame to accommodate these two factors.

Spin-on Oil Filter
Spin-on Oil Filter

Oil Filters

Oil filters play a critical role in a V-twin oil delivery system. Oil suspends dirt and debris and moves it away from critical engine parts and easily-clogged ports and passages. As the oil passes through the membrane(s) of the filter these impurities are removed. Filtration reduces the chances of harmful deposits accumulating between moving parts, and lengthens the effective life of the oil.

Most modern motorcycle V-twins use “spin-on” canister filters. A gasket around the mouth of the filter forms a leak-proof seal. The filtering membrane(s) may be constructed of pleated paper, fiberglass, or synthetic fibers. Some filters even employ magnetic components to remove metallic shavings.

Braided Oil Lines
Braided Oil Lines

Hoses and Fittings

Dry sump oil delivery systems require external hoses and fittings. Special hoses and fittings are designed to withstand the heat, pressure and chemicals present in the system. Hoses are available in flexible neoprene, nylon and braided stainless steel. Rigid alloy tubing is also available. Oil system components should be inspected regularly to check for cracking, chafing and leaks.

Oil Cooler and Hardware
Oil Cooler and Hardware

Oil coolers

Oil coolers can be added to the oil delivery system to aid in the dissipation of heat. An oil cooler performs like the radiator of a car; effectively increasing the surface area of the system exposed to the air by using a series of fins or heat sinks. Cooling the oil increases its overall effectiveness and may extend the life of the oil.

Oil Gauge and Hardware
Oil Gauge and Hardware

Gauges and Sensors

Today’s motorcycle oil delivery systems make use of sophisticated gauges and sensors to help monitor this crucial system. Gauges may use either a digital display or analog movement (a needle and scale) to display the feedback. Temperature and oil pressure are typically monitored. Oil sensors use energy, in the form of pressure or heat, converted to electrical energy to drive the gauge displays. Gauges should be constructed, especially when choosing analog gauges, with high accuracy and quality components. These gauges should also be shock-resistant to withstand the rigors of road vibration.


This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

Show Details
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
ClickscoThis is a data management platform studying reader behavior (Privacy Policy)