In the following picture, you can also see the teeth on the slider gear and main drive gear which allow them to be mated together. Also remember that the slider gear is keyed to the mainshaft, so anytime the mainshaft is turning the slider gear is turning. Keep in mind that the mainshaft goes through the main drive gear, which means that the mainshaft can be turning while the main drive gear is sitting still. First to go in is the mainshaft, with the main drive gear and slider gear installed on it. Now that you are familiar with some of the major components, lets start installing them into the transmission case to see how they work together. The slider shaft provides a mounting point for the slider fork, the part that actually shifts the gears when you move the shift level forward or back.įrom top to bottom, a well used mainshaft, a countershaft and a slider shaft. The countershaft's only job is to hold the cluster gear and, unlike the mainshaft, it does not spin. On the other end of the mainshaft are the components that make up the kicker assembly. The mainshaft not only holds the main drive gear and the slider gear, but also completely exits outside the transmission case to hold the clutch assembly. This transmission uses three – the mainshaft, the countershaft, and the slider shaft. The next major group of components are the shafts.
The slider gear turns with the mainshaft and can slide back and forth to mate with different gears. These mate with the similar protrusions on the main drive gear and are used when the transmission is in first gear. Just like the main drive gear, it also has protrusions on its face. Using its own two gears, it engages with the second and third gear on the gear cluster. The last gear to discuss is the slider gear, which keyed to the mainshaft but slides back and forth. The main cluster gear contains the three gears that make this a three speed transmission. This gear rides on needle bearings on one end and standard caged bearings on the other. This three gear unit is what makes the transmission a three speed – the smallest gear is first, the middle second and the largest third. Next on our tour of gears is the cluster gear. The main drive gear transfers power out of the transmission and to the rear wheel. Also note the protrusions on the face of the gear, their importance will be discussed shortly. It rides on a bronze bushing which is press fit inside the gear and the bushing has small grooves added to its surface to allow transmission fluid to lubricate it as it spins on the mainshaft. As you can see in the photo below, this gear has a threaded portion which is where the rear sprocket is mounted for the chain drive. The first of these is the main drive gear which is mounted half inside and half outside of the transmission.
Your standard transmission case, coated on the inside with Glyptal.Ī VL transmission uses three different sets of gears to transfer power from the engine to the rear wheel.
This eliminates the need for adjustments and opens the door for other benefits like sharing fluids between the engine and transmission. The transmission case can also be incorporated into the engine case, making the engine and transmission one unit (such as a Harley Sportster). For my VL and other Big Twin Harley's, the case is a completely separate unit which can be moved back and forth within the frame to change the tension on the chains. Obviously, the case houses all the transmission parts, but there are a couple main variations on this piece that are noteworthy. First and foremost is the transmission case. To start, let's go through some of the major components you'll find in any transmission. READ MORE: Tennessee, a '33 Harley, and Me Modern transmissions are certainly more sophisticated than this vintage piece of machinery, but the overall design concepts are still roughly the same. I'm currently rebuilding the three speed transmission in my 1933 Harley-Davidson VL, and I'm going to take you through the ins and outs of this unit to give you a better idea of what is going on in your own transmission. When it comes to transmissions, it seems that what is happening inside is a lot more of a mystery to the average rider. We may not all be able to rebuild one ourselves, but we do have the basics of 4 cycle operation under our belts. As motorcycle riders, I feel that most of us have a decent understanding of how an internal combustion engine works (Those of us of a certain age at least - JM).