Clutch

Clutches and parts for clutches

Changing the clutch and disks is no big deal. Of course, all necessary parts as springs, washers, friction disks etc. should be obtained beforehand - preferably from Barnett, for your 883 or 1200, for Dyna, Softail, Tourer or V-Rod. Add the right amount of PanAm primary oil and you're ready to go.

Do I have to change the clutch? When do I need to change the clutch plates?

The biker knows that the clutch is due for replacement at the latest when the engine speed goes up when acacelerating but virtually nothing happens at the rear wheel. As inconspicuously as the clutch does its job, it is painful when it fails. However, the clutch rarely needs to be replaced completely. In most cases, new friction disks are sufficient, only sometimes the complete set of disks, i.e. the friction and steel disks need to be changed. If the engine performance has been modified, the springs should also be replaced. The original clutch springs are of course only designed for the original engine output. The clutch should separate easily without the biker having to go to the gym.

When do I need a high-performance clutch?

In principle, after a considerable performance cure. A Big Bore Kit or a complete Sidewinder kit, plus an Andrews B Grind camshaft, this ensemble can make a standard clutch sweat. The Rivera Pro-Clutch or Barnett Scorpion clutch are then the means of choice for capturing the galloping power and reliably transferring it to the road.

Why does the motorcycle need a clutch? What does a clutch do?

When motorcycles were young and not much more than a bicycle frame with an engine in it, there were no clutches. A drive belt went directly from the engine to the rear wheel. The rider pushed the vehicle, jumped on the saddle with luck and daring and ... putt, putt, putt ... the journey began. There were no traffic lights and if you did have to stop, you stalled the engine and pedaled on again when you wanted to continue.

A clutch to transmit the power became necessary when chain drive and manual transmission became standard. From 1915 onwards, Harley-Davidson motorcycles with three-speed transmissions were equipped with a well-functioning friction plate clutch. All clutches up to the present day are variations and improvements of this design.

How does a clutch work on a Harley-Davidson?

There are two components on the transmission shaft: a fixed component with external teeth (we call it the clutch hub) and a loose part such as a drum with internal teeth, which runs on a bearing on the shaft or on the clutch hub. The drum is called the clutch basket or clutch shell and is connected to the engine shaft via a chain. It doesn't really matter how the bearing is designed, the main thing is that it guides the clutch basket in such a way that it has the same axis of rotation as the shaft and hub and covers the hub. In the interior space formed by the clutch basket and clutch hub, there are (metal) disks, some with external teeth that engage with the internal teeth of the basket, others with internal teeth that engage with the external teeth of the hub. One type of discs is additionally equipped with a friction lining and both types of discs are located alternately one behind the other. Due to the toothing, the pulleys are positively engaged with the basket and hub, but can move axially - i.e. "out and in" in the direction of the shaft. The entire stack of pulleys is covered by a mechanism that is connected to the hub or basket and pressurizes the stack with spring force via a thrust washer. The friction between the disks due to the spring pressure creates a frictional connection and the clutch transmits the force. It is engaged. The disengagement, i.e. the separation of the frictional connection, is carried out by a mechanism that releases the spring pressure. (This allows the clutch disks to disengage from each other. The engine is uncoupled from the transmission and the clutch is "disengaged".

But not all Harley-Davidson clutches are built the same?

The clutches at Harley-Davidson differ from model generation to model generation in the shape and size of the disks, the design of the clutch basket and hub, the type and number of springs and, of course, the release mechanism. Only some parts are interchangeable or compatible. Most, however, are not and when selecting spare parts, you must pay attention to the type of clutch. This is determined by the model and year of manufacture. In addition, there are clutches from different manufacturers such as Barnett, BDL, Cannonball, Primo, Rivera, which often use similar-looking parts, but differ in many dimensions.

Why does the clutch on my Harley rattle? Will my clutch break if it makes that ringing noise?

Counter question: do you ride an open belt? Yes? Then the answer is no, your clutch is not broken. Although the clutch plates are interlocked with the basket or the hub, they can be moved axially in relation to the transmission shaft. So they are loose. Loose means they have some play. This play must be somewhat greater with dry-running clutches than with those that splash in the primary oil. The oil dissipates the heat, the dry clutch is at a thermal disadvantage. And since your primary drive runs open, you will hear this as clicking, ringing, rattling ... especially when you disengage the clutch.

If you're not running an open belt, you may have a primary housing made of sheet steel. This was original on Knuckleheads, Panheads and Big Twin Flatheads. And the clutch in the sheet metal primary case also runs dry. In this case, you should inspect the steel plates of your 3-, 5- or 10-finger clutch (3 is original, 5 and 10 are accessories, you will have one of them). Harley-Davidson originally fitted these plates with small spring-loaded balls for damping. Often the balls or springs are rusted or the springs are lame, the lubricating oil of the primary chain does not really reach the parts. Steel pulleys from the accessories do not have these dampers at all. As with the open belt, this results in a noise when the clutch disengages. Not really dangerous, but sometimes annoying. Then the only thing that helps is to replace the steel disks. However, if the check reveals that the six blocks in the clutch basket are worn, replacing the plates will not help.