Hi,
Pump it up! The X2 looses performance as any other kite if not pumped real hard.
Also make sure the set-up is correct and that the rider is not flying the kite oversheeted in stall.
A proper set up 18 is solid as a rock in the sky. We have had no such problems here and we use them a lot.
Thanks,
Bengan
http://www.colonawatersports.com