Rigged up drag racing shift kill switch

[radbassist]

Ok, I was young - Drag racing my GS1100 in Woodburn Oregon....I worked in a MC shop in Snailem Oregon so I was learning stuff right and not so right. I asked my boss - "if I can't afford straight cut gears and an air shifter, what else can I do to shift faster?"

He says "well, you can ground your ignition system with your horn button that will momentarily kill your ignition while you're putting "up" pressure on the shifter - It will take you to neutral and then when you let up on the kill button, your "up" pressure will take you to the next gear and you can keep the throttle "pinned" wide open the entire time".
Made sense to me. Tried it. Went to the track. Ended up running slower times than when I was using the clutch....AND as an ADDED bonus...Fried my regulator rectifier. But I can't say for sure that was the cause but I suspect it was...
( I got 'in between ' gears a lot going from 1st to 2nd and 2nd to 3rd - Zzzzziiiinnnngggg! - fawk ) :highly_amused:

And no, I didn't honk everytime I shifted :highly_amused: I unplugged the horns

 

[fasteddie313]

My father has a similar setup on his big bore 1964 Norton Atlas..

I don't think you are supposed to ground the entire ignition system though, just the kill switch on a momentary button like a horn button..

His Norton has a funky shifter on the wrong/right/flat track side and upside down iirc 1st is 1 up and the rest 4 down..
"Stand on the shifter and hit the button wide the F open" he says..

Anyway the tequnique is to take off in gear and in the middle of your gear rev push the shifter towards the next gear while still WOT and when you want it to shift just tap that killswitch button while holding the shifter..

All it takes is a flick of the kill switch to take enough pressure off the gears for it to pop in to the next one and as soon as you've let off the button your still WOT in the next gear instantly..

Once you've shifted let off the shifter for it to reset and put your pressure back on it toward the next gear, in the case of the Norton down.. When your ready for it to shift again just flick that killswitch and repeat..

He says it's fine on the Norton tranny but I have no idea on jap trannies or any others.. He has Mikuni carbs and other mods on the Norton and he has been ragging it hard since 1966 and it's still around to this day so I guess there is some merit to this shifting technique.. Though it's been rebuilt a few times in it's life including recently..

 

[radbassist]

Nice ! My boss was an old flat track racer. Tough as nails. I guess he wasn't crazy

 

[TxGSrider]

I think they make some pressure sensitive linkages that fit between your shifter and shifter that do the same thing... but you don't have to think about.

I would think an enterprising person could wire one up using a modified rear brake light switch assembly hooked to the shifter and then tie it to your kill switch.

Im sure someone will chime in and tell me why it won't work... and they'll probably be right. lol!

 

[bobgroger]

I think they make some pressure sensitive linkages that fit between your shifter and shifter that do the same thing... but you don't have to think about.

I would think an enterprising person could wire one up using a modified rear brake light switch assembly hooked to the shifter and then tie it to your kill switch.

Im sure someone will chime in and tell me why it won't work... and they'll probably be right. lol!

Drag racers use an adjustable kill box set to as low as they can and have it shift consistently. Usually 40-60 milliseconds, WAY faster than you can push and let off a button. They also have an autoshift feature for your air shifter. That can backfire if you spin off the line and it shifts.

http://www.mpsracing.com/products/MPS/au01b.asp
http://www.orientexpress.com/p-8305-orient-express-nextup-engine-kill-control-unit.aspx