The cast iron disc in the pressure plate survives at 11,000 rpm? Incredible.
I would have bet real money that it would disintegrate at that speed.

the only thing i can say is if u balance everything well most items will hold its when it gets the shakes is when stuff brakes

no gearbox .it runs a halibrand q/c diff.

How do you get such high reliable rpm?

I would have thought that these engines would explode at those rpm.

What cylinder head do you use.
Is it a standard A12 motor that has been modified, or is it only a A12 block with a GX cylinder head or something else.

Aseries are renouned for good high reving. My street A14 does 9000rpm with 10:1 comp and good GX head work. So raising the comp up to 12 or 13:1 with right fuel and some other slight work gets these Rpms pretty easy.

Good work, bet it squeals nice and loud up high

What dizzy, ingition you have on the a12?... i have elec S2 bluebird dizzy, great spark.

No gearbox and probably winters diff, hallibrand or similar (billet alloy/steel 26-30kg diff!)
These Speedway cars run direct from the crank so no gears just high revs to throw you violently forwards.
As for 9000rpm peak these guys run sustained runs at 10,000rpms plus as they have no gears and no stock crank will last so to say its easy to get 12,000rpm you got another thing coming and compression wont get you there or other common mods, most of speedway racers dont reveal everything as theyve worked for a long time to get to where they are and reveal it to anyone.
So guys his not using the common stuff you and I use like for example the bluebird dizzy is a joke compared to what these guys use.
Look at his ebay Auction and youll see one of his setups.
Man I feel so underpowered
By his profile Darren is the dude whos pioneered the OHC a series!!!
RESPECT!!!!

Yes, high compression is not needed to get high RPM.

Most likely it runs a dry sump system to get 10,000 rpm or more.

Ive heard that 10k rpm a series nice as they are do tend to stretch the lower crank journal bolts and need to be replaced after every meeting...

have not replace bolts in two years .never had the trouble

no i still run a wet sump ,have never had the need for dry sump if the wet ones made correctly

well guys thanks for your imput but beleave it or not i have gone back to the bluebird dizzy and its still working fine .as im now working on cheap h/p motors so guys can make them without ppk telling them they need stuff that they dont ,there are to many guys with secrets and overcharge for simple items if u want to know anything that i maybe able to help with u are welcome to email me anytime .