Updated: Jul 4, 2019
Once its central theory is understood, the skill of clutch-less gear up is naturally mastered in a matter of minutes. Clutch-less up-shifting is one of the easier systems you can employ on a motorcycle to enjoy smoother bike control and quicker acceleration. If done properly (and after a small amount of practice, you will), clutch less up shifting will not harm the gearbox – some even argue it lessens wear and tear.
We, at Siima MotoWear have done some research and we present you with how clutch less shifting works on motorcycles:
Though it's problematic for many to primarily accept, up-shifting without a clutch is in many ways modest than the usual pull-the-clutch-in-while-rolling-off-the-gas, shift-up, let-the-clutch-out-smoothly-while-rolling-back-on-the-gas method most of us grew up practicing. Instead, simply reload the shift lightly, then rapidly let off the throttle slightly and then back on and-presto-you're in the next gear.
When done appropriately, a clutch-less up shift sounds and senses like that of an electronic shift, and no, it's not offensive to the transmission; uncountable years of the SR staff racing their private bikes stand witness to this.
The key thing here is the saying "done correctly." Luckily, this is as easy to feel as it is to do.
First, recognize that while accelerating, even mildly, you're able to slightly lift (reload) the shift lever with your toe without causing the transmission to shift or pop out of gear.
By lightly, we mean perhaps two to four pounds of upward compression for a moment before your anticipated shift point. Then, as the tach sweeps past the chosen rpm, just crack the throttle slightly off, then immediately back on, as speedy as a blink of an eye.
Don't entirely shut the control; only close it enough to momentarily reverse the acceleration load on the transmission before returning the twist grip to its initial position. Don’t forget to release the pressure on the shift lever after the shift to let the mechanism to ratchet back and index the next gear.
Once grasped, however, you'll find that it works at any speed and any rpm. Primarily, it takes a bit of trial and error to get the mastery and feel for it, and diverse bikes may require somewhat different amounts of throttle change, but you'll know when you hit the right blend.
To understand how clutch-less shifting works, it’s helpful to have some knowledge on the insides of a motorcycle gearbox. Motorcycle gearboxes usually have a shift drum and shift forks with six dissimilar detente positions in which the shift drum can exist in.
On almost all modern bikes, those positions are 1st, Neutral, 2nd, 3rd, 4th, 5th and 6th. When shifting from say 3rd to 4th, 3rd gear is detached before 4th is engaged – in that period between those two gears, your gearbox is not in any gear. This isn’t true neutral, in effect it’s a ‘no man’s land’ and this differs from a standard manual car gearbox, where you shift through neutral between each and every gear.
To shift between gears then, the drive train must be discharged, allowing the
decoupling and re-coupling to occur. One way to do this is to jerk the clutch lever. But the way we want to do it is without the use of the lever. We do this by quickly rolling off and then on the throttle.
The process is this:
1. Put an upward force on the gear selector.
2. Blip the throttle. You don’t need to totally roll off the throttle, but enough to see the engine spin speed dip for a portion of a second and then roll back on the throttle.
3. If done properly, your upwards pressure on the gear lever will jump on the next gear.
4. Take the pressure off the gear lever until ready to up shift again.
Clutch less up-shifting allows for faster shifts, often time smoother shifts. The main reason why often time clutch less downshifts are not good, particularly on the track, is due to engine braking.
Check the video below to learn more:
Back in the old two-stroke era, you had almost no engine braking, but with our bigger 4-strokes in the present era, whenever you let off the gas, the engine itself is working against the rear tire, decelerating you down. When you are moving at high speeds, such as on the track, are under hard braking, etc., this can cause your rear tire to get light and then lock up.
This is where you want the regulator of your clutch, slowly feathering it, so the tire does not lock up. Other than that, downshifting is as easy as up-shifting without a clutch; it's just a question of a reverse. Up-shift - cut the throttle, bang up the gear. Downshift - blip the throttle to some extent and knock it down.
Any thoughts on the subject? Leave your comments below.