03 October 2017

Clutchless gear change - is it safe?

Some motorcycles with great big flywheels and big gears, like many Harleys and some BMW Boxers, need the clutch – or at least a little clutch – for nearly every shift. Most sportbikes only need you to use the clutch to pull away from stops and for the shift from first to second gear.

At slow, around-town speeds, we mostly use at least a little clutch to shift anyway; you don’t need to pull the lever all the way in every time you use it. But if you’re steadily accelerating, and especially at WOT (wide open throttle), you’ll find that after second gear, if you roll the throttle closed just enough to unload the driveline, for just a split second, with your toe pressing on the lever, then third gear will slip right in without using the clutch at all. Fourth, 5th and 6th will slip in even easier since the gaps between them are increasingly smaller. Done smoothly, it’s no harder on your gearbox than using the clutch.

Rolling off the gas just a smidge to “unload” the drivetrain is exactly what all quick-change electronic shifters do by cutting the ignition just long enough to allow the next gear to slip in, the best of them for an imperceptible amount of time. Naturally, the need to save every split second on the race track is what caused these to evolve. With the latest seamless gearboxes used in MotoGP, there’s no lag at all.

All a bit brave for yours truly. 
I'm gonna keep on pulling that left lever.
Really don't want to end up with a gearbox full of swarf. 

How to do it properly: Vid 1 Vid 2
Original article: www.motorcycle.com
Further reading: www.motorcyclenews.com

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