Possible to fit a Quickshifter?

[750steve]

Ok, this is more of a microsquirt related question but this board seems to get more traffic.

Is it possible to wire in a quickshifter (on a motorcycle) to MS2/uS? If so how is it done?

[DonTZ125]

Hi, Steve.

Yes, you can use a quickshifter, but the implementation can be tricky, depending on the output from the shift controller. There is no way (that I can recall) to signal spark cut / retard in B&G code; the Extra code has the flatshift settings, but even that's tricky with a sequential gearbox. The car guys use flatshift to hold the revs at a certain rpm while they hold in the clutch and shift the gears, but that's not what you're trying to achieve. Every quick shift mode for a bike I've ever seen has been for a clutchless upshift at WFO - that's what you want, correct?

You'll need an adjustable timer to control the spark (or fuel) interrupt, and then a means of blocking the spark or fuel signal. It might be easiest to wire the spark (or injector) power through a high-power low Rds-on mosfet that is interrupted for however many milliseconds by the timer. I have something similar in the works for bikes using the OEM ignition, but it blocks the safety signal. Shouldn't be too hard to modify to this sort of service ...

[750steve]

Hiya Don, man you're everywhere!, thanks for helping me again!

This sounds a little more complicated than I 1st thought then. I had thought that the 12V ground to the coils could be connected to a kill switch which, when pressed, would then kill the ignition, maybe my head simplified things a little too much there!! I don't know what way the Dynojet 'barrel switch' that's connected to the shift rod in their modern stuff works but I was going to try to find out, I kinda hoped it was a momentary switch (like a bar mounted thumb operated kill switch is) which would break the ground to the coils & shift at the same time.

[DonTZ125]

Hi, Steve.

Using the kill button is exactly how I used to work it on my old TZ, but it isn't easy. Too long of a push, and you lose momentum; too short and the transmission isn't unloaded enough to shift. Also, my bike was CDI, and I was grounding out the trigger signal; I'm not sure what kind of flyback effects you'd need to worry about when constantly chopping the coils on a TCI ignition (I'm sure it's been done, so shouldn't be too bad). The ideal solution is a timer circuit that accepts a 'go' signal, whether from a shift-rod switch or a push-button on the handlebar, that chops the ignition for a set time.

I've finished my circuit, and I'm ready to go to market. I can offer a bare board for $25, or $50 for an assembled unit, plus shipping. This doesn't include a shift-switch or push-button.

[750steve]

Don, are you telling me you have a 'timer' box that will kill the ignition for a set time when used with a switch (such as the shift rod switch that Dynojet use?), ie. the 'brain' for the Q/S?

How does it wire in to uS? (Not looking you to give away secrets, just seeing if im capable of the installation! LOL)


We have HM stuff over here that would probably work ok, but its mega £/$! I have one on my race bike & its flawless, kill time is set to 65ms & you can set the small 'brain' with it to 'push' or 'pull' depending on if you're running race shift or not. On my project bike i happen to ve running race shift which i like best, 1 up, 4 down, so i thought it would be complimented nicely with a Q/S, best of all the race shift was an accidental thing when i added 2010 ZX6R Rearsets!


http://www.hmquickshifter.com/ (used by maby BSB & WSB teams)

[750steve]

I'd probably be interested in your tip over sensor too! Just seen it on uS forum, looks like an essential piece of kit!

[DonTZ125]

Hi, Steve. Yes, this is the 'brainbox' for a quickshift system. You work with a shift sensor all the time; with a push-button switch, you'd press down on the shift pedal then push the button. Just as with the shift sensor, if the timing is correct the transmission unloads just enough to snick smoothly into the next gear, then power is re-applied so smoothly you don't notice anything happened. If the timing is too short, nothing happens; if the cut is too long, the bike lurches.

The unit can be configured depending on the type of ECU. Most OEM controllers have a safety circuit that chops spark if the sidestand is down while in gear, so the easiest thing is to interrupt that circuit. The uS has no such option, but the Extra code has a 'flatshift' function, so I've included the ability to wire in and ground the input pin. Unless I'm mistaken, B&G code has no such ability, so you have to do it the hard way - cut the power to the coils. The quickshifter includes an option for a heavy mosfet; you would wire the +12v feed for the coils from the main relay (or FP relay, depending on your preference) to the QS, then to the coils. When the QS receives a signal, it interrupts the safety circuit, grounds the flatshift pin, or cuts the coil power feed, depending on the system, all for that brief moment. There is an adjusting pot to set the cut time.

Those HM units are pricy! Mind you, anything used for WSB or MGP is going to be $$$!

As for the tip-over switches, I can't believe no-one is flogging these. Yes, this is mostly car guys, but there are still quite a few bikes around here!

[750steve]

Very ingenius Don! Have you a set kill time on your Q/S box or can it be set by the user?

[DonTZ125]

There is an adjusting pot to set the cut time.

[750steve]

Err, oops! I missed that bit! lol

Ok, i'll see if i can pick up a switch for the gearchange & i WILL be in touch, tip over sensor as well.

[DonTZ125]

Wonderful - at your convenience!

[750steve]

Don, im on ebay looking, what wiring on the switch will i need to operate the Q/S?

*edit* False alarm, i see most have just 2 wires

[DonTZ125]

Hi, Steve.

Two wires is fine; it's looking for a grounding signal.

[750steve]

Thanks Don. So, its wired into the +12v, not the ground side? The reason i ask is those LS2 coils im using suck up alot of current, 140MA each, so im wondering if the Dynojet Q/S switch wires will be able to cope with that kinda current

[DonTZ125]

The quick shifter has the following wires:

• +12v; light or heavy, depending on the switching mode
  GND; light - only used for the timer circuit
  Signal; light - grounds the flatshift signal or interrupts the safety signal; not used in power switching mode
  Coils; light or heavy - leads to the coils or safety switches, depending on the switching mode
  QSS; light - out to the Quick Shift Sensor or push button

Since you're using a uS with B&G code, you'll be using power switching mode - full coil feed to the +12v wire (from the main relay or FP relay), full coil feed to the coils. The GND and QS wires are light-duty, only carrying mA. The Signal wire is unused in this mode.

The Dynojet QS wires will be carrying less than 2mA - I think they'll be able to handle it ...

[750steve]

Ah right, i gotya! I was thinking more like 10+ Amps for those coils! I see what you're doing though