Going To The Next Year | H-D Screamin' Eagle Six-Speed Transmission Install

01. Here is the H-D six-speed with a 66-tooth sprocket in a black case $2,799.95. Also a new sidecover bearing door with the new longer pushrod, gasket, cable clip, and ball and ramp kit, $199.95.

01. Here is the H-D six-speed with a 66-tooth sprocket in a black case $2,799.95. Also a

If you are a serious rider racking up a lot of hours on your bike and see tons of highway miles then you know how important it is to have a smooth and well running motorcycle. Guys are always looking to hop-up the motor with pipes, air cleaners, headwork, and so on, but what about hopping up the transmission? If you are running around on a stock bike with a five-speed in the gearbox then you should be fine, but what about the guy with the big-inch motor? We're sure he wants a smooth ride as well.

A few months ago we installed a 95ci motor hop-up kit from R&R Cycle on our '04 Road King, and we were very happy with all the new power. However, we could also feel how hard the motor was pushing at the high end and felt that we needed to shift to keep the pistons from flying out of the top of the cylinders. We needed to bring the rpm's down without losing acceleration and all that feeling of power.

Enter Harley-Davidson's Screamin' Eagle six-speed transmission. The transmission features helical-cut gears for increased strength and mechanical noise reduction featuring higher contact ratios and quieter meshing to carry more load and engine torque. All the gear teeth are cut and hard finished directly on the shaft, eliminating under gear splines, and providing improved gear mesh alignment for higher tooth strength and lower noise. For reliability and durability the output sprocket and final drive gear are supported by a high-capacity double row angular contact ball bearing replacing the smaller single row ball bearing. With the output sprocket spline and locking nut increased in size you get improved joint strength as well. To make the transmission shift quicker and smoother, Harley replaced the old-style moving gears with lighter dog rings to ease shift effort. The dog rings are diamond finished for smooth operation along with a lightweight composite shifter drum to reduce the throw of the shift lever. With the H-D Screamin' Eagle six-speed we should get a 15 percent reduction in rpm, and gain a much smoother ride.

Here is how the ratio breaks down from the five-speed to the six-speed. The gear ratio is the same up through Fifth gear; however with the added Sixth gear, at 0.86:1 is where we will lower the rpm's but still keeping the same rate of speed.

We stopped by Pomona Valley Harley-Davidson in Pomona, California, to get the new H-D six-speed installed as we snapped some photos. Shop tech Brian Breeland placed the '04 Road King on the lift and started draining the fluids and removing all the big parts that would be in the way like the seat, exhaust system, and running boards, then disconnected the battery.