Pipe *pipe = [[Pipe alloc] initWithImageNamed:pipeImageName];
[pipe setCenterRect:CGRectMake(26.0/kPipeWidth, 26.0/kPipeWidth, 4.0/kPipeWidth, 4.0/kPipeWidth)];
//set the physicsBody before X/Yscale
pipe.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:pipe.size];
[pipe setYScale:height/pipe.size.height];
[pipe setPosition:CGPointMake(320+(pipe.size.width/2), abs(pipeYOffset + (pipe.size.height/2)))];
[pipe.physicsBody setAffectedByGravity:NO];
[pipe.physicsBody setDynamic:NO];
This may help you. I think this is a bug in ios7.1.