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DIY Quickshifter concept

9K views 23 replies 12 participants last post by  Auser6guy 
#1 ·
Hi all, ive been thinking.
A quickshifter is nothing but a momentary ignition cut. That cut lasts 65milli seconds long and drops power just enough so that the shift goes smoothly.

How can it be done on the cheap?
First we need to sense that a shift is happening and then we need to change ignition timing for 65ms or so whilst shifting

Sensing
A simple switch can do it but it needs to be on the shift rod

Affecting ignition
On an injected bike changing the resistance of the inlet air temp so that the engine things it needs A LOT less timing
Or momentarily cutting power to the coils

So... any ideas in a cheap way to sense the shift beside the obvious strain gauges that the name brand manufacturers make ?

I reckon a raspberry pi with some simple programming could do the smarts part.

Any other ideas ?
 
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#3 ·
Wonder if a reed relay and a magnet on the pushrod/behind the pedal would be precise enough. Not sure it'd move enough for the magnet to get far enough from the relay.
 
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#5 ·
If you had a channel on the arduino looking for a change in the signal rather than trying to produce an actual switching effect, a magnet and coil (or light and diode) might work.

You might need something a bit more complex to allow sensing the difference between upshifts (where you probably want it to kick in) and downshifts (where you would probably rather it did not, to allow rev matching). But a properly designed sensor and software could do that (maybe the mag field gets stronger on upshifts, and weaker on down, or there's a light blocking disc with an opening that only lines up during upshift).
 
#6 ·
If the swith would kill ignition what happens when you shift from neutral to first on low rpms? Also that half switch to neutral? With actuall switch in rod it might just kill ignition and stall the bike!? Or you have to use it as a sensor amd arduino, raspberry.
 
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#8 ·
Look up FSR: force sensing resistor. A simple flexible package 0.012 inch thick that in its relaxed state shows a resistance near infinite, but when a force is applied the resistance drops significantly. Ideal for a basic voltage divider following +5V (Vcc) buffered by an op amp which will tie the analog input to the MCU to 5 volts as long as the FSR is at rest, then progressively move toward ground as force is applied. As to the free play that needs to be taken up before the actual shift is initiated: about 0.007 inch.

The biggest advantage here is using an analog input to the MCU makes it possible to fine tune the trigger point by varying the voltage level: either a simple pot accessible to the rider on the fly, or up and down buttons. Endless possibilities.

The housing is really quite simple: a piece of half inch .065 wall 2024 tubing with a fixed boss for rod attachment at one end which is where the FSR is mounted as well, and a constrained and spring loaded plunger sliding on a teflon bushed guide screwed into the other end of the housing. Note only one sensor ... for upshifts only! Kinda solves the engine dying when shifting into first problem.

Of course if you prefer GP shift, as I have for the last three decades, just mount the sensor the other way around.

More to come

Rob
 
#9 ·
Would you want a raspberry pi which had to live in a very vibey outdoors environment to have control of cutting your ignition? Sounds just as bad an idea as fitting a $9.99 alarm and immobiliser from China.
 
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#18 ·
That's easier because the ignition cutout is triggered by the same power source as the shifting itself, and the shifting event has a short, consistent duration. Get some clutzy ape pushing the leaver with his toe instead of a nice air mech, and you need shit like a sensor and maybe some logic.
 
#19 ·
No sense in re-inventing the wheel. Some other cheap bastard already did it.

https://www.speedzilla.com/forums/honda-rc51/62440-el-cheapo-quickshifter-mod.html

Something similar could be made with 2 micro switches. One on the throttle body to ensure it only activated under WOT and the second being on the shift shaft "sensing" when pressure is going in the upshift direction. Both needing to be switched to disconnect the coil, CDI, fuel pump, or something like that.
 
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