Chopper Basics: A Simple Look At How Choppers Work...If you want to learn how to build a chopper from start to finish and study all the fine details involved in every step of the process, this article is not for you. It's simply too large a subject to discuss in one simple article. But if you want to learn the basics of how a chopper is built, and how each of the parts work, you may find this article extremely informative. This article is probably best for the novice chopper enthusiast who wants to take the fist step in learning how to build a chopper. If you want to ad in any additional information, please contact us and we may include it in this article. We would love to expand on this and make an advanced presentation. And with your help on how to build a chopper we can accomplish this together. Also, if after you have read this article you want more detailed information I recommend these video's (DVD's) from Covell. If you are not quite ready to jump in on building your custom chopper, I recommend you read this material (see the bonus material too): How to build a chopper frame.Following is the brief description about the parts used in chopper motorcycles and a basic guide to what's needed in the process of learning how to build a chopper... Chopper Basics: The FRAME The most important step in learning how to build a chopper is understanding the frame. The frame is one of the most important components on a motorcycle, especially on a large motorcycle. The frame must be designed strong enough and built rigid enough to:
Frame Construction The frame is made from high-strength seamless steel tubing and utilizes a high tensile strength welding process to extremely tight tolerances. Chopper Basics: Types of Frames: 1) Hidden Shock Frame
A) Steering Head B) Frame C) Rear Forks and Pivot Shafts D) Shock Absorbers 2) Rubber Mount FrameA) Steering Head B) Frame C) Rear Forks and Pivot Shafts D) Shock Absorbers 3) Rigid Frame
A) Steering Head B) Frame Chopper Basics: The SUSPENSION SYSTEM (Front & Rear) In learning how to build a chopper beyond frame design, the suspension system is the chief ingredient in determining the handling capability of a motorcycle. The suspension system is responsible for keeping the wheels on the ground and absorbing the shock as the motorcycle passes over uneven surfaces in the road. Both the front suspension (telescoping front forks) and the rear suspension (rear swing arm and shock absorbers) operate by compressing and extending as the motorcycle passes over a bump, absorbing the shock of the bump to keep the motorcycle stable. The front and rear suspension utilize springs for the up and down compression and extension, and suspension dampers to stabilize the up and down movement. Without the suspension dampers, the springs in the suspension system would continue to bounce up and down after each bump creating a “rocking horse” effect. FRONT SUSPENSION Motorcycles use two types of telescopic front fork assemblies: conventional and inverted. Each assembly consists of two fork tubes which contain springs, spring dampers and oil. The fork legs slide on the fork tubes. The tube or leg extends and compresses within itself as a shock absorber. The two types differ in these ways. On the conventional type, the fork tubes are captured by the triple clamp positioning the fork leg at the bottom of the assembly. The inverted type was developed on racing motorcycles to place the heaviest and strongest part, the fork leg itself, in the triple clamp - thus inverting the assembly. This design gives more rigidity to the fork, reducing fork tube flex and lessens the unsprung weight, improving suspension response. The triple clamps (trees) and fork stem hold the front fork tubes to the frame and keep the tubes aligned. The fork stem is an integral part of the triple tree and fits through the steering head allowing the forks to be turned to the right and left.
Inverted Fork Suspension Conventional Fork Suspension A) Triple Clamps and Fork Stem A) Triple Clamps and Fork Stem B) Fork Legs B) Fork Legs C) Fork Tubes C) Fork Tubes REAR SUSPENSION There are two types of rear suspension exposed shock absorbers and hidden shock absorbers. The rear fork is attached to the frame with the pivot shaft. The arms of the rear fork (often called the swing arm) hold the rear wheel and keep it aligned. The rear shock absorbers mount to the rear forks and the back struts of the motorcycle. The ability of motorcycle to handle effectively while cornering, breaking, etc. depends in part on the suspension system having the right amount of “controlled flexibility.” Over time or under certain conditions if your suspension seems too rigid or too spongy, it may need servicing or adjustment. Chopper Basics: The POWERTRAIN The power train is composed of: A. V-Twin, 107 cubic-inch, four stroke engine B. Chain driven primary drive C. 5-Speed transmission or 6-Speed transmission D. Belt driven final drive down. Chopper Basics: How the Engine Works Chopper Basics: The BRAKING SYSTEM The front brake is a hydraulic disc type, which is operated by the hand lever on the right handle bar. It is composed of: Chopper Basics: The CLUTCH SYSTEM A. Clutch hand lever THE CLUTCH ASSEMBLY: Simply put, the clutch assembly is composed of round discs called “clutch plates” which are contained inside a clutch housing (often called the clutch basket). These plates are pushed together by CLUTCH HAND LEVER & CABLE When the clutch hand lever is pulled, the clutch cable acts against (or relieves) the spring tension within the clutch assembly to release the friction grip inside the clutch. As the clutch plates separate from each other and slip, this de-couples the gearbox from the engine. The clutch assembly is a mechanical wet clutch. Mechanical means that it does not operate by hydraulic pressure. A wet clutch means that the clutch assembly operates immersed in an oil bath. This not only helps to keep the clutch assembly cool, but also washes away loosened friction material from the clutch plates, keeping the surfaces clean and free of debris. Chopper Basics: The ELECTRICAL SYSTEM The electrical system provides power for your motorcycle. It is powered by a high cranking, long -life, 12-volt battery. The electrical system can be divided into five sub systems: Chopper Basics: The FUEL SYSTEM B. Fuel supply valve C. Carburetor and air filter D. Throttle grip & cable E. Fuel lines The fuel system on your motorcycle is a gravity flow system, so no fuel pump is required. Although it is a simple system, it must perform the complicated task of blending (or mixing) the fuel and air together in the right proportions and supply this mixture to the engine. FUEL SUPPLY VALVE: The fuel supply valve (petcock) is a manually operated on/off valve designed to control the fuel flow from the gas tank to the carburetor. CARBURETOR: The carburetor is the central part as well as the most complex part of the fuel system. Its primary job is it to atomize (break up) the fuel into small droplets, and mix the atomized fuel with the right amount of air. This mixing (or metering) of fuel and air is called the airfuel ratio. It is precisely here (the carburetor’s ability to atomize and properly meter the air-fuel ratio) that performance, as well as fuel efficiency, is won or lost. CARBURETOR OPERATION: Chopper Basics: CONTROLS AND DISPLAYS TURN SIGNAL SWITCHES: Chopper Basics: MIRRORS The speedometer registers miles per hour of forward speed. The odometer registers the number of miles the vehicle has traveled. B. TURN INDICATOR LIGHTS: The green TURN indicators will flash when turn signals are activated.C. HIGH BEAM LIGHT The blue BEAM indicator light, when lit, signals that the headlamp high beam is on. D. TRANSMISSION NEUTRAL LIGHT: The green NEUTRAL light turns on to indicate when the transmission is in neutral. E. OIL INDICATOR LIGHT The red OIL indicator light, when lit, signals that oil is not circulating through the engine. The light will come on when the ignition is turned on prior to starting the engine. With the engine running, this light should be off except possibly at low idle. If the oil pressure indicator light does not go off at speeds above idling, it is usually because of an empty oil tank or diluted oil. In freezing weather the oil feed may clog with ice and sludge, preventing oil circulation.
GEAR SHIFTER: The gear shifter is located on the left side, and is operated with the toe of the left foot. There are five or six forward gears (depending on model) and no reverse. Pushing the lever all the way down (one full stroke) shifts the transmission to the next lower gear, while lifting the lever all the way up (one full stroke) shifts the transmission into the next higher gear. The operator must release the gear shift lever after each gear change to allow the lever to return to its central position before another gear change can be made. The neutral position is between first (low) and second gears. First gear is the last gear position that can be found by pushing the lever full strokes downward. To shift from first gear to neutral, lift the lever half its full stroke. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Copyright Custom Choppers Guide |
