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Motorbikes use sequential constant mesh transmissions , no need to match revs or disengage anything . Dusty
Too glib Dusty.So do use the clutch on your bike when shifting ?So quick shifters are pointless ?Why not just crash it through and let the transmission crunch the crankshaft up to the new rpm ?
New to me 18 BMWR1200RT has pro shift and up shifts you can hear the exhaust note change for a split second as the ignition is cut to aid shifting. On the downshift it has an overrunning clutch to help smooth things out. Overall I like the upshifting and do it pretty well. The downshifts are OK with a closed throttle and not very good under power, like needing a lower gear for a hill.
I test drove a Nissan 370Z manual with synchro rev matching. It was pretty impressive and negated the need for heel/toe downshifting. Haven't tried a bike with a quick shifter, but I have preloaded the shifter a few times and closing the throttle before pulling the clutch the transmission slipped quietly into the next gear. Not sure I need a bike with a quick shifter for the way I ride these days.
A couple of my riding buddies ride modern Yamahas with slipper clutches, apparently you can just bang them through the gears.I assume a slipper clutch must disengage the drive for a split second am I correct?Anyway none of my Guzzi's will ever get a clutches change although I did ride one with a broken clutch lever once, its quite easy to do if you take it slow.
The shifter has an up and down pressure sensor talking to the ecu. The ecu also knows what gear the bike is in the road speed and the target rpm for the lower gear for the road speed. At the sensor lever threshold pressure the ecu via the FBW throttle pops the rpm to the target figure for the next lower gear thereby offloading the gear drive dogs from the overrun load on them and the foot pressure drives the shift lever and the gear selection. Anyone that's ridden a motorcycle knows you need to rev match on the downshift while using the clutch to get a clean and smooth engagement. The other option I've seen used is to just kick it down through the gears and let the slipper clutch do the work which I don't recommend myself. I've seen professional racers do clutchless downshifts before throttle blippers and standing by the side of the track into slower corners was a horrendous to hear experience. Troy Bayliss used to do it in WSB if the story I heard was correct until Tardozzi got onto him about the amount of transmissions he was wrecking. My track Ducati 1198 has a Techtronics quick shifter that unlike more popular but basic cheaper units knows gear position and road speed and can be upgraded to downshift blipping with an optional actuator to drive the cable operated throttle bodies. I haven't bothered with it.Ciao
The slipper works as the name suggests. When the lower gear engages instead of the the engine trying to instantly go to the revs the road speed dictates the clutch slips until an equilibrium is met. Problem is it's hard on shift forks and shifter mechanisms due to needing to overcome the back drive load on the gear dogs when down shifting and no slipper clutch works seamlessly for all gears and road speeds.My RSVR Aprilia had a vacuum operated one which didn't stop the bike trying to throw me over the high side out of turn 11 at Phillip Island when I short shifted the wrong way a few years ago.Ciao
And manufacturers are finally realizing that it is not just powerful bikes that benefit from slipper clutches and have started putting them in bikes generally bought by new riders. Now if they would just start putting cruise control on lower displacement bikes.
all i can add Pete is that for us older riders they are very counter intuitive. You are tempted to help things along by trying to match engine rpm's like an old school clutch less up shift. WRONG! Keep the hammer down and let the ECU take control . My Tuono is only quick up shifts, and is remarkably smooth if you have faith and leave the throttle constant and shift. Wear to engagement dogs is primarily due to rider error and not staying on the throttle when upshifting. Remember when you are hammer down you are accelerating and a split second ignition gap is all it takes to smoothly roll you into the next gear. The problems arise when you let off the throttle and confuse the program. They are a joy on a bike trying to kill you as fast as possible. You must come to Maine and take Dan's for a spin.
This is an interesting discussion The best I can come up with going is that A) The shock load is dissipated to some extent by a slipper clutch if fitted or the rear wheel losing traction momentarily B) The engineers sized the components and selected appropriate materials that can accommodate the loads appliedI assume that going clutchless up the box, the instantaneous loads are the same but in the opposite direction?
As for clutchless shifting, and quick shifters, that has been discussed as well. I have been riding clutchless for years, even on my old clunky XS bikes. A little preload on the shifter, and blip of the throttle, the V7 snicks through the gears as well as my FJR and FZ1 did.
I must be missing something How do you blip the throttle when the bike is in gear, surely that would cause it to accelerate?PS Bullitt Mustang