Crappy spring, idk. In my tornado s30 I never broke a spring I never even changed the clutch.
The way the clutch works is while the flywheel is spinning at idle the spring is strong enough to keep the clutch from spreading out and engaging, so centrifugal force makes it engage and disengage. I had heard of people getting a strong spring to sort of time when the clutch engages if u have a tighter spring it will make it engage at a higher rpm making it have harder launches at a stand. Just like in a 1:1 if I left the clutch out at 1500rpm in my Mazda it takes off gently but if I let the clutch out at 4k rpm then it spins the tires and takes off hard.
Trying a better spring could be beneficial, also depending on where the spring broke u could rebend the end of it to hook back on the points where it goes in the clutch and it would make the spring tighter making it launch at higher rpm