I grew up riding little Honda motorcycles all over cities and campgrounds. I understood how to engage the clutch to get the bikes moving off a stop. I also rode a bicycle all over before I could get a driver’s license, so I can turn on 2 wheels with ease.
What I never did understand was how to work the clutch in the friction zone on a big Harley Davidson open road bike. Cars and trucks have a dry clutch and you don’t want to slip that clutch much in order to minimize heat and wear on the single disc system.
Motorcycles have a “wet” clutch that is multi disc and designed to slip a lot. This is the backdrop, here’s why that is important.
Part 1. Understanding the Friction Zone. Start with a bike on flat, level ground. Pull the clutch lever all the way in and put the bike in gear. Give it a little throttle, let’s say 1500 to 2,000 rpm and slowly let the lever out until the bike just starts to creep. That is the beginning of the “Friction Zone”. You may call this the starting point if that helps. As you let the lever out very slowly, the bike moves more and pretty soon your feet are up on the pegs, but you are still holding the lever in a little and the clutch is slipping. You are in the zone that lies between the beginning and full engagement, where you let go of the lever and the clutch is fully engaged.
In this situation of partial engagement, you can regulate the speed of the bike by applying the brakes in varying degrees. A little brake or a lot of brake will speed up and slow down the bike. Remember, you are still slipping the clutch while holding a constant engine speed.
Practice this maneuver with as little engine speed as you can. Just work on straight line starts and get accustomed to the feel of the clutch, throttle and brake. You are now learning the friction zone. It’s important to understand it is a Zone, not just a single point. Start, roll and stop. Over and over until you feel yourself becoming one with the bike. This is one of the most important things you will learn about riding a big open road bike.
Part 2 Now that you understand the friction zone, let’s learn to use it to our advantage. With the clutch fully engaged at a very low speed, the engine has very little power. If you enter a tight turn with the clutch fully engaged, the engine doesn’t have enough power to pull you back upright in the event that you get too far over. The engine will stall and you fall down, go boom. (direct quote from Tweety Bird commenting on the sudden demise of kitty cat).
When you lean your bike over to take a corner, the power of the engine can pull you back upright if you tip over too far. The engine is your asset. The engine can save you. Engine speed saves the engine. If the speed gets too low, the engine stalls.
This is the same concept as flying an airplane. You can only gain altitude as fast as the engine can pull the plane. Pull the stick back too far and the engine can’t pull it. You’ve stalled the plane. Take a corner too sharp, at too slow a speed, and you’re going down.
I was riding my Harley Ultra Limited on a road trip. I’m over 70 years old and too weak to manhandle a thousand pound bike. I’d stopped for gas and headed out via the front of the gas station. What I didn’t realize was that what looked like pavement was really black gravel and there was no entry to the street, just a tall curb. I recognized this too late. I knew if I stopped in deep gravel, I’d go down. I turned to try to get back on pavement. It didn’t work. The next thing I knew, I was headed for a huge curb drop. The front tire hit the gravel side of the curb and the front of the bike flew high up into the air. The frame of the bike hit the curb hard and then the back of the bike hit the curb. I was tipped over further than I could control. I was tipping over and the bike was going down hard.
Instinctively, I pulled in the clutch, hit the gas with everything I had and popped the clutch.. As I came down, the power pushed the bike back upright and I was able to stabilize the bike and come to a stop sitting on the bike. A guy witnessed all this and came running over to help. He said he never thought I would save the bike and keep it up. I told him I never thought I could do that, either. 🙂
That was how I learned the true value of using the power of the engine to keep a bike from going down. Engine revolutions (RPMs) provide the power, the clutch connects the power to the wheels.
Now that you understand how to begin to master the friction zone to get your bike moving, you can use it to start the bike moving from an uphill stop. You can either hold the front brake to hold the bike in place, or use the rear brake and hold your bike up using your left foot. It’s a good idea to practice both techniques on level ground. Use the engine to pull against your brake on level ground to help you learn how to do this.
Now, let’s learn how to use the friction zone to corner a bike. Start out by pulling in the clutch on every turn, so you use instinct to set the friction zone. As you practice wider turns, you’ll get better at finding the friction zone right away. I practiced right turns by trying to follow the edge of the curbing through the turn. You want to always look at the end of the turn as you enter it. Use the rear brake to regulate your speed, not the throttle.
The rear brake will keep the bike stable and using it to regulate speed can help keep the bike up. Under ideal slow speed conditions, the clutch and throttle don’t change. The brake controls the speed. The engine speed is up to provide the power needed to keep the bike from tipping over and the clutch enables it to have the necessary speed.