ive been looking through my new morristech ECU software, and it has a display of the injector duty cycles, what is considered a normal max duty cycle for a set of stock injectors on a stock motor. ive seen it reach into 70% when i tramp it.

uh 100%. which means the injector is open all the time.

No, you don't want to see 100%, ever and in a factory car that is healthy, you won't.

100% duty cycle means that either the fuel system is unable to supply enough fuel that the ECU is dictating (due to mods / raised boost) or a broken / misreading sensor.
eg: imagine if the air flow sensor said that there was twice as much air coming into the engine as normal. The ECU will try and get twice the fuel into the engine to keep AFRs' in line.

the only first hand experience I've had with Duty Cycles was a friends 1L charade - running 18psi boost and the injectors couldn't cope, so boost was reduced to 15psi and the car was able to be tuned and ran quicker.
It was a 3Cyl, so half of the cylinders and 1/3rd the capacity of the Magna, so not sure if relevant at all :)

id still like to think i had the more concise answer :P

Most people like to keep the duty cycle under 85% at it's maximum, You can run up to 100% as long as your A/F is still what you want but obviously it's very close to drifting into the lean area which is far from ideal! So in an ideal world if your injectors are over 85% duty cycle you would fit larger ones and re-tune. Hope this helps.

Cheers Dave

thanks, thats exactly what i wanted to know.