Quick shift

Originally Posted by flymo

this is exactly what a race quick shifter does, as fitted to every World Superbike, MotoGP and many others.

Only difference is that it does this electronically using a pressure sensetive switch built into the gear shift linkage. The moment that you attempt to move the lever it kills the ignition for a predetermined duration taking the load off the gearbox.

As long as you are not clumsy with it, after a bit of practice it is pretty easy to do on upshifts. Continue to use the clutch on downshifts though or you'll lock your rear wheel into a slide if you're not careful or maybe even over rev the engine to the point of breaking it.

+1. The upshifts can be super quick and smooth with a bit of practice, but doing it on the downshifts is a complete waste of time as long as your clutch lever works. It would be about as unnecessary and almost as detrimental as swapping your hands and using your left on the right lever.

[flymo]

Originally Posted by Baph

Whilst good theory, in practice you can change down the box without either locking the rear or blowing the engine/gearbox up. Again, I wouldn't advise anyone to do it though, purely because of the risks involved.

I still change down the box without the clutch from time to time... but I accept the risks associated.

Thats fair, although I think the main reason for not using the clutch is speed, faster changes. Its a racing technique thats very common.

During a race its pretty normal to do rapid shifts down the box during the braking zone. Trying to do this without the clutch (and no quickshifter) is extremely difficult to do when you are under pressure.

Probably fine to do under gentle riding conditions but I dont really see the point personally.

Downshifts are easy tbh. Doesn't hurt the gearbox unless you're a moron.

Originally Posted by gettin2dizzy

Downshifts are easy tbh. Doesn't hurt the gearbox unless you're a moron.

How do you rev-match without disengaging drive?

Originally Posted by sinbad

How do you rev-match without disengaging drive?

By changing down where the gears cross over. You just put a dab of throttle on to take the weight off the gearbox.

Originally Posted by gettin2dizzy

By changing down where the gears cross over. You just put a dab of throttle on to take the weight off the gearbox.

Where the gears cross over?
I don't understand. Rpm will always be higher in a lower gear at any given speed- if you don't disengage drive and rev match then the revs will be forced up by the rear wheel, and however you do it, you're not disengaging drive if you don't use the clutch (unless you're going from 2nd to neutral -rev- and then to first ).

Originally Posted by sinbad

Where the gears cross over?
I don't understand. Rpm will always be higher in a lower gear at any given speed- if you don't disengage drive and rev match then the revs will be forced up by the rear wheel, and however you do it, you're not disengaging drive if you don't use the clutch (unless you're going from 2nd to neutral -rev- and then to first ).

Simple really. When you're changing up, you roll off the throttle & snick up when the gearbox isn't loaded (well, in practice, when the load is so small that it'll easily jump to the next gear).

When changing down, you need to bring revs up a little, so you open the throttle a little. There's a small time delay in that increase in RPM getting to the drive chain. During this time delay there's relatively little load on the gearbox again and you can snick it down a gear with ease.

With practice you can change gears both up & down without the clutch, without really unsettling the bike (I find clutchless downshifts easier when I'm hard on the brakes TBH).

However: Shifting down without the clutch has far more chance to go wrong. If it goes wrong, the consequences can be pretty severe.

I find it quicker to have good clutch control tbh I suspected that I fudged my 675 gearbox by clutchless up shifting so I tought my self to be fast on the clutch, I wouldn't recommend it without a racing or equvilant clutch setup.

Down shifting without the clutch - I just blip the throttle. It works. Upshifting all the time without the clutch, was useful at getting on the gas early yesterday.

USD gearbox helps too.