Bullet 4.5

[Nas]

This was my first kite from 2002 ,Its still in good shape but recently it started holding a lower angle and won't go to zenith.I replaced the lines and the brake line length is quite good but the kite would fly but not high and a bit sluggish going side to side . On the buggy it stays behind and becomes a nuisance . It also has a new fold across its length when fully powered. The cells are ok nothing busted , could they be full of dirt ?
Can someone point to the problem ?

[B-Roc]

Could be dirt but if you have a crease in the middle of the kite that is a sign of a bridle issue - likely stretch or maybe one line shrank over time in storage. What size bullet? Does the line run top to bottom or side to side? I'm assuming side to side if the AoA has decreased and the kite is falling back in the window. The crease is occurring at the problem. Either the bridle legs above and below have stretched or those legs have shrunk or a pigtail slipped. You can probably fix this with some fiddling and extra pigtails. You may even be able to fix it by physically stretching the "shrunk" bridle legs.

[Nas]

Thanks ,I will work on it .
Yes it is side to side and most probably bridle stretch as one bridle line is stripped already .