Quickshifter...rather weird discovery

[tedski]

12 minutes ago, Skidood said:

Yes.... on a normally closed switch, holding the shifter up will open the switch contacts...and with an open circuit on powerup, the ECU will deem this a fault and disable the QS, or assume no QS is installed.   

But when you install the QS for the first time, you have to enable it.  The enabling procedure is to hold the shifter up.  That's why I think it's normally open.  There's probably a logic check in the boot process of the ECU that checks if that circuit is closed (shifter up) and then flips the "QS Installed" bit.

[OZVFR]

You're all assuming it's either open or closed.

It could be like alarm systems that look for resistance.

IE: high resistance is open, low resistance is closed, no resistance (open circuit) is fault.

 

[CRFan250]

Ride more, worry less, lol

[Heli ATP]

What does a motorcycle quickshifter do? How does it work?

The factory-fit quickshifter on most current motorcycles uses a switch in-line with the rod that connects the gear-lever to the gearbox. In the case of the most common – an upshifter – as the lever is pushed up (on a race box it’s pushed down), the switch is first compressed and contact made. A spring adds weight to that switch, but once compressed and contact is made (or broken, depending on whether the switch is normally-open or normally-closed), the force being applied to the lever is transferred to moving the selector inside the gearbox, and the next gear ratio is selected.

It’s a simple design, but it relies on a positive shift being made by the rider, and it takes away the direct feel of a solid linkage rod, as you’re introducing a degree of sprung travel to the system.

Activation of the switch causes the spark plugs to be momentarily cut, ceasing drive. It’s the same process (but faster) as briefly rolling off the throttle while you flick into the next gear.

Why do some quickshifters feel better than others?

Different brands of gearbox feel lighter or heavier than others in their operation – the Yamaha Niken quickshifter, for instance, feels a lot more heavy and clunky than the one fitted to the MT-10.

The mapping of the ECU, the mechanical set-up and even the chain tension all contribute to the feel of a gear shift, and hence the quickshifter.

Link here...

QUICKSHIFTER AND HOW IT WORKS

[Skidood]

On 6/28/2021 at 11:21 PM, tedski said:

But when you install the QS for the first time, you have to enable it.  The enabling procedure is to hold the shifter up.  That's why I think it's normally open.  There's probably a logic check in the boot process of the ECU that checks if that circuit is closed (shifter up) and then flips the "QS Installed" bit.

That's a very good point.  

[SKYFLIX]

Based on my own troubleshooting with the QS, my thoughts are that it is actually normally closed. Otherwise, how can a QS enabled bike determine if the QS is faulty *after* it is enabled. A Normally Open circuit would be no different than a non-existent (or faulty) one. I have an aftermarket QS on order and I plan on testing this theory once it arrives. This switch supposedly takes less force to activate than the OEM.

[Skidood]

43 minutes ago, SKYFLIX said:

Based on my own troubleshooting with the QS, my thoughts are that it is actually normally closed. Otherwise, how can a QS enabled bike determine if the QS is faulty *after* it is enabled. A Normally Open circuit would be no different than a non-existent (or faulty) one. I have an aftermarket QS on order and I plan on testing this theory once it arrives. This switch supposedly takes less force to activate than the OEM.

The weird thing is, to turn QS on or off, you (apparently)  use the same procedure, hold the shifter up and turn the key.  So I wonder if the ECU is programmed to look for a "shifter up" condition,  and simply set the QS mode to the opposite of what it was already set at. (either on or off)

[fjray]

On 6/29/2021 at 9:02 AM, CRFan250 said:

Ride more, worry less, lol

This!