I have not found an answer to this question yet.
I have the 2t model.
I looked through the parts catalog and service manual but I didn't see the specs for the stock springs in there. The red big spring is rated at 2000RPM's and the little springs are rated at 1500RPM's.
I did replace them, like color/rating for like and noticed a drastic improvement in performance, though it's still not performing as well as I expect this scooter to perform. I also noticed a significant difference in length of the big spring - the old one was nearly 2cm shorter than the new. I did not use OEM parts.
This is my second 2009 People 50 2t, I bought my first one new, and it was stolen after a year. Booo.
My original People 50 2t was super zippy and I could easily reach 45mph on a flat. I bought a used People 50 after that and it doesn't come near performing the way my old one did. I have a friend, also with a 2009 People 50 2t that rides as good as my old one did, so I use it for performance comparison with my "new" one.
Before changing springs, my scooter would shudder on take off, as if the clutch was slipping. Between around 15-25mph I would lose power, then from 25 - 35 it would accelerate again to a max of about 38-40. Forget climbing even the smallest hill.
After changing springs, it accelerates very smoothly through all power bands with no shuddering. My max speed is now only 35mph. Hills are still tough.
I have 7gm rollers in the variator, I'm planning on putting the stock (8.5gm) rollers back in to see if it improves one way or another, as soon as I find the time.
Any other ideas of how to get my poor scooter performing the way it should be would be awesome!