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Clutchless Shifting


Laffo IBA#34115

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I have, now and then, for various reasons. However, I'm responding because I know a fellow with a RT police model, with a sidecar attached, who shifts that way all the time. He has no use of his legs, and has a rod attached to his shifter that he grabs with his hand to shift. The bike has lots of miles, and he rides a lot, so it seems to work fine. I'm sure he has it down well what rpm's to shift at, and the timing of the throttle so you don't clunk the transmission during the shift. My guess is the sudden torque change from a bad shift could be hard on the transmission over time. Those BMW transmissions are pretty tough though...

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Paul Mihalka

Once in a while I shift without using the clutch, but not regularly. I do suggest that everybody learns and practices doing it. That way with a broken clutch cable or bad clutch throwout bearing you can still ride home or to somewhere where you find help.

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I have up-shifted quite a bit without the clutch, but I have never down shifted without the clutch. How would you recommend practicing? RPM's very low, throttle completly off? Just curious, I might start practicing, never really thought about what I would do if I lost my clutch. Thanks Phil

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George Brown
I have up-shifted quite a bit without the clutch, but I have never down shifted without the clutch. How would you recommend practicing? RPM's very low, throttle completly off? Just curious, I might start practicing, never really thought about what I would do if I lost my clutch. Thanks Phil
For starters let off throttle and nudge it out of gear. Then with slight pressure on shift lever apply throttle -- when engine speed is matched with drive train it should slide into the lower gear. Remember at a given road speed the engine speed increases with each lower gear.

 

Pratice gently at first until you get the hang of it. Start with the upper gears first as they will be easier than the lower gears.

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ShovelStrokeEd

George, there are no neutrals between the gears. The best way to accomplish a cluthless down shift is to momentarily release power from the drive train by very slightly backing off the throttle and then, with firm jab on the lever kick it down into the next gear while applying a bit of throttle. The above sentence took a lot longer to read than the entire action should take. It really just about occurs all at once, in particular, the jab at the gearshift should take place conincident with the quick off/on blip of the throttle. You might experience a balk or two or a little jerk until you get the timing down. BTW, something to keep in mind is that the percentage difference between gears rises as you go lower in the gearbox. 6th to 5th is easy to do, second to first much harder.

 

Short of a broken clutch cable or something whacky with the hydraulics, I can see no good reason for doing this. Well, one, upshifts while drag racing, an activity for which the BMW is singularly unsuited.

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Paul Mihalka
For starters let off throttle and nudge it out of gear.
To put the gears into a false neutral between gears is always bad. To downshift without clutch: go off the throttle - put some firm but gentle downward pressure on the shift pedal and hold it - give it some throttle - it will snick fairly smoothly into the next lower gear.
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George Brown
To put the gears into a false neutral between gears is always bad. To downshift without clutch: go off the throttle - put some firm but gentle downward pressure on the shift pedal and hold it - give it some throttle - it will snick fairly smoothly into the next lower gear.

 

Paul and Ed, Thanks for jumping in here and setting me straight. Its been a while since I've downshifted on a bike without the clutch. I guess I was thinking more about my Audi. Your both correct: false neutral is not a good place to be. Thanks again.

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I only use my clutch on my RT on pull away and down shifting and when you stop. I have found out on my RT that its much much smoother if you do clutchless upshifts and no 2 gear slips. On my GT I do the same but its a much smoother bike overall so no difference in gear changes with or without clutch. smirk.gif

 

TCS

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I have found that clutchless upshifting is the smoothest way to shift the RT.

 

Clutchless shifting does require close coordination between the throttle and the shifting lever, hand foot coordination.

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russell_bynum

Sorry about the size. a friend just put this on his sport bike.

 

That's a great way to go for racing.

 

For those who aren't familiar...that's basically a switch mounted inline with the shift rod so that downward pressure on the shift pedal closes the switch.

 

The switch is connected to the PowerCommander, and when the switch closes, it briefly cuts fuel to the motor to remove the load from the transmission. This lets the bike snick easily up into the next gear while the rider leaves the throttle WFO.

 

AFAIK, it doesn't work for upward pressure (downshifting), so you're still using the clutch for that.

 

Since I don't race, and a tenth a lap isn't a big deal to me, I just very briefly dip the throttle when I press down on the shift pedal to unload the transmission and allow the upshift without the use of the clutch.

 

But if you're a racer type and a tenth a lap means several seconds at the end of a race, then this is a good way to make time.

 

I don't think (though I may be mistaken) that this is available for the BMW version of the PowerCommander.

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