I identified that I have some stretched front lines, and feel my kites not flying as good as it use to with a bit of back stalling when fully sheeted and sluggish behaviour
I followed the video below for tuning my bar.
They say to tie off the lines to the nail before the pig tails then check and tune what you need to tune, mine being the fronts by adjusting the front line pig knots to bring the slack on the chicken loop back in.
Yeah no worries but what about if the pig tails them self's are stretched? I presume they are meant to be equal as well? check the pic below. Should i just get some new ones or move the knot even further back to account for the pig tails as well.
in the pic I have undone the knot so yeah the lines are a bit longer than they should but even with the knots in they were longer than the steering line ones.
I had the same problem with regular hindenburgs when fully sheeted.
a more experienced kiter told me to let the bar out so the kite catches more wind
it doesn't sound right, but i **** u not, it works
and while testing this theory
I've found that in slightly lighter winds where I was trained to do figure 8s to power my kite I can sometimes just pump my bar in and out to get enough power
hope this helps
ps. if u'r still unsure about ur lines most shops will check them for free, I've had very good service from the guys at airborne
When i tuned mine i left the pigtails connected then get someone to pull on the bar and just tied knots at the same point on each pigtail so they are the same length when bar is nearly touching the chickenloop 
Gee that does look odd that the top red one is longer. I think it came like that from the factory. If the front lines are different lengths it can make the kite pull slightly to one side a bit like a car when the front wheels are out of alinement.
Normally it's the lines that stretch not the pigtails. Make sure that when re tie them the distance from the bottom of the loop to the knot is the same on both sides. Not sure with core kites but most company's do have agustments under the floats at the bar. Make the backs lines a bit longer using the ajustments under the floats or just pull in a touch of depower and see if the kite flys right.
Check that every thing is even length when everything I'd back together on the bar.
If it still fly weird take it to the place you bought it and let them look at it and try and tune it for you
Someone can correct me if I'm wrong but I find it difficult to think the pigtails themselves would stretch that much? If in doubt just buy a new set, only $20 or so.
If it's an older Core kite you are riding there are three knots on the steering lines at the kite, try attaching your lines to the bottom knot if you haven't already, your next option is to slide up the bar floats, undo the lines and tie in some new knots to make the steering lines a little longer.
That covers the back stalling, for the sluggish behaviour check the pulleys and bridle lines. The pulleys will cause excessive wear on the bridle lines, to the point where the line can't squeeze through the pulley any more. The pulley closest to your line connections does the most damage, followed by the other pair higher up in the bridle. The pulley on the wingtips will eventually wear out the line as well. In the past AKS have spliced new lines for me and sold me the other bits and pieces to replace the worn lines. It made a massive difference and was well worth spending a couple of dollars and getting it all sweet again.
