motorcycle quickshifter diy

hello i need some help finding a circuit i can use for my diy motorcycle quickshifter.

for simplisity lets assume the triger is a push switch with a 12v feed. I need a circuit which once it receives the 12v signal from the switch closing it will create a pulse which grounds the coils cutting off the spark. the pulse needs to be variable (by changing a capasitor or somthing no need for anything complicated) between 50-100ms.

i have found this https://www.electro-tech-online.com/custompdfs/2013/08/MC14538B-DPDF.pdf
would that work? anyone know of any thing that would?

thanks for you help.

That would provide a delayed variable width pulse as you require, but you would need to build circuits round it to make it do what you want.

Ok thanks.
What else would I need to do to get it to work? Would I need a relay or somthing on the pulse circuit? Would a relay even be able be able to react fast enough?
Thanks again

You need 'something' to disable the ignition, and probably something faster than a relay - it really depends how you're thinking of doing it?.

I was going to cut the ignition by grounding the coils as I know of a few quickshifters which do it this way. So I was thinking the pulse would activate something else which would complete the circuit to the ground the problem is I don't know what I can use for this as you said a relay would be to slow

Is your ignition system the old Kettering type (i.e. mechanical contact-breaker plus capacitor plus coil)?

No I dont think so. If it helps he bike is a 58 sv650 the first of the twin sparks I believe. I will have a look in the owners manuel when I get home and try to find out what ignition system is used.