The history of Harley-Davidson transmissions has undergone transformation since its time of inception. The inaugurating model OHV 61 cubic inch EL in the year 1936 is a hit model called Knucklehead. The design of the transmission is the amazing factor in this bike. The transmission model was followed until 1986. The bike was running with the same configuration for nearly 50 years. Of course, one cannot deny the fact that there were variations during the initial period. Some of the transformations include 3-speed with reverse, 4-speed and hand and foot shift.
The first design had knuckles and pans in the same case. In the year, 1965 electric start was introduced. The transmission case was enlarged to support the electric start resulting in a quarter inch length in transmission. The case was extended to accommodate all the new ingredients. There was not much of change until the alternator came into existence. Now the alternator again affected the transmission where the primary has to be removed to fit the alternator. The main shaft grew. Changes were in progress until the dead of 4-speed in the year 1986. The four speed was thrown out as everyone wanted another gear.
The year 1980 saw a revolution with the FLT series motorcycle that was introduced by Harley. The change came in the form of a rubber mounted engine that came with 5-speed gearbox. This resulted in a major design transformation. Harley listened to the view of the riders when they wanted a five-speed gearbox instead of a 4 speed. Riders thought that the 5th gear is for overdrive. Though, the final drive ratio is 1:1. It gave the engineers the base to increase the performance of top speed.
It did not stop with that, riders wanted more speed, and therefore, one more gear was added. The 6-speed cruise drive transmission was introduced in the year 2006. This resulted in the upgrade of the Harley gearbox. But the snag is that it is not as good as the aftermarket transmissions found in the market. Make no mistake, this is a serious bike, this is not your average manual treadmill reviews magazine. Some top brands that produce overdrive gearboxes include Rev Tech, Milwaukee Twins, Baker and Jim’s machine. The latest in the transmission arena is the high gear option that is .86 to 1, .80 to 1 that is less than the 1:1 stock. This results in low engine rpm when put at a particular speed or faster speed while at the same rpm.
In the mid-1990s, Harley Softtail came up with an overall ratio of 3.36:1. The number of teeth in every gear or pulley located in the primary or secondary drive is determined by the ratio. Though, a problem in this overdrive system is that if you try to slow down in the overdrive gear, the engine will choke when you try to accelerate the vehicle. This can lead to damage to the engine health. To avoid this, it is advised to downshift if you want to accelerate.
There are alternatives you can try while you add an overdrive to improve the overall ratio of the vehicle by reducing the rpm of the engine at a particular speed. Motorcycles that have a secondary chain drive find it easier. The market is flooded with chains of varied lengths that can fit different sprockets depending on the customization. Belt secondary has made things complicated. With belts fixed in the application, there are certain limitations in how to customize the overall ratio of the bike. Moreover, it makes it difficult to reinstall and remove the components. Lowering the overall engine rpm is fine if you modify the drive ratio. You can also use 6-speed overdrive transmission to lower the engine rpm.Read More Motorists first love – Harley Davidson – Must know information