Air Shifter with the MSD RPM Box

[RacingJake]

Has anybody try using the MSD RPM box hooked up to your air shifter?

I like the idea of just changing pills to make the bike shift?

Jake

[lecroy]

Hey Jake, did you look at the sliders yet?

I guess I am not sure what you meant by changing "pills". There is now way to have the MC-2 drive the shifter directly. I assume you wanted to use the lower rev. limiter as a kind of RPM switch and "pill" is the little resistor pack?

Normally the lower limit would be set just below where the slider is going to catch and the upper limiter is to save the engine.

One way is to use the Dyna Shift Counter to drive the MSD box. The Dyna unit is a one-shot that can be used to signal the MSD to kill the ignition. There are switches in the Dyna to set the kill time. You would still need a trigger. This is normally where something like the Dedenbear would come in. I could be something as simple as an RPM switch.

There are simple diagrams on how to wire the MSD box on their website. I also show how my old bike was wired with a manual clutch and button shift. Just bring up the following:

http://dickey.no-ip.org/turbo/schematic.gif

Hope this helps.

[RacingJake]

Hey Lecroy

The Slider's are a little out of my price range so I'm going with my stock setup for the time being. Maybe later this year I'll pickup a lockup.

And you are right in that I was thinking of trying a RPM switch plugged into the high or low side of the MC2. Heck I don't even know if that would work so I was thinking of using my Shift light by hooking up a relay and some SCR's to send 12 volts to the air shifter. But I don't know how much lag time is involved and after all is said and done maybe my thumb is just as fast or faster.

KISS might just be the solution

Jake

[lecroy]

Relays can act very slow. 100mS +. Larger ones may be in the order of 250mS (0.25 seconds). This is one of the problems with the Dedenbear (all relay drives).

If you already have a shift light, the only thing your would need would be a one-shot and a couple of FETs to drive the solenoid and the MC-2. I think you would be looking at under $10 when it was all said and done. The shift light is good, but I think anything you can do to remove the driver from the bike is going to be a plus.

If you get it working, I would leave the shift light on the bike. It helps to keep people guessing about what it is your doing.

I agree with KISS for what it is you are currently doing. Even the hand clutch is fine. It's hard to justify putting any money into a bike this old.

[rosco15]

Dont forget the shift light flashes when you turn the ignition on. So be sure to run it from the shift light thru the air shift button to the air shifter. This way it wont shift unless you have the shift button pushed in. As you pass the tree just jam your thumb on the shift button and hold it down to open the circuit and let the shift light do it's thing. Also acts like a safety switch. No accidental shifts. Takes the shift light and button to work. Be sure to check your rules at the track about an auto shift. I dont think this is a good thing.

Ryan

[RacingJake]

Dont forget the shift light flashes when you turn the ignition on. So be sure to run it from the shift light thru the air shift button to the air shifter. This way it wont shift unless you have the shift button pushed in. As you pass the tree just jam your thumb on the shift button and hold it down to open the circuit and let the shift light do it's thing. Also acts like a safety switch. No accidental shifts. Takes the shift light and button to work. Be sure to check your rules at the track about an auto shift. I dont think this is a good thing.

Ryan

That's a VERY good idea Ryan !!!!

[Anonymous]

Most bracket tracks do not care about the auto shift. Especially if it is an outlaw track. NHRA or IHRA might care though.....

AMA prostar series prohibits it in the bracket classes.