I just picked up a 5m storm kite and gave it a go today wind 27 to 35 knots onshore.
It felt good on the beach and I could fly it from 10 to 2 in figure 8s and it felt fine then when I went to dive the kite to take of on my board it seem to drift down to 9 o'clock with very little power and then shoot across to one side of the window and fall out of the sky giving great amusement to my mate on the beach watching, I tried again and this time when I dive it, it got to about 930 and when I tried to drive it back up it did a 180 and went screaming across the window again.
This was not only pissing me off but it was also scaring the sh-t out of me. I understand this will undoubtedly be pilot error but I have never had this happen on my 8m,10m or 12m.The kite is a proto type of well known brand and I was told equal length lines. The only other guy out came in and flew the kite and said the back lines needed to be longer. I understand that a smaller kite will take some getting used to so was hoping that anyone with vast small kite experience may be able to give me some tips. I was using a 50cm bar with 25m lines, I know the bar is probably to long but thought I would still be able to fly the thing. I am 89 kg and on a surf board any suggestion greatly appreciated as I am going to try it again tomorrow. Thanks

As "wheels' knows I was there yesterday in the freezing insane conditions.
I dont mind fessing up here that it was a protype of the all new Ocean Rodeo 5M "Storm" kite.
Thanks to 'wheels' for not mentioning the kite brand as it could be taken here on the forum as a big negative.
I dont really want to comment on 'wheels' problems at this stage as this is the first time this kite - a storm specific design from Ocean Rodeo - has been flown by anyone in Aust & it is still very much a 'new' kite even in hometown Canada.
Trusting that serious reviews will follow once its available for demo by more riders. Yesterday was a hell day to be on a new kite esp 1st time up.
In its favour I can say it looked amazingly rock solid considering the blustery conditions.

BUT this post does open up the discussion of kiters testing new demo gear.
WeAt KSS we do heaps & heaps of demos - just about everything we sell is available (to experienced kiters) anytime.
The problem you (as in ALL kiters) have when demoing something new is that you have been taught by your own kite quiver exactly how to fly those particular kites. In even the most subtle ways every different size, model & brand of kite requires equally subtle different ways of piloting it to get the best out of that particular kite. Without necessarily being aware of it its just the way we fly our kites.
Some can pick up a previously unflown kite & dial themselves into it really quickly & easily - others will need to work at it more before they are getting the genuine feel of how the new kite needs to be flown.
When trying a mates kite OR demo'ing a new kite my suggestion is to be aware that it will be a different experience.
A few things we stress when handing out demos are:
1) New kite = always use an old familiar board (& vice versa when demoing boards). This is an absolute must to gauge whats different.
2) Go back to watching your kite. If you are not looking at it you wont gain any appreciation of how its reacting to your auto conditioned input from the bar. It may be turning way too soon or way too late from what you have grown used to. Then it again it may need to turn sooner or later than your old kites??? Test them out - dont just try to fly them the way your own fly best.
3) Always try - if possible - to test the new kite or board back-to-back with the kite or board you are looking to replace.
4) If you want to demo a few different kites to help you make a decision try to demo as many as possible back-to-back; same day, same place , same time.
Make your demo sessions test sessions. Dont just grab a kite & flit out & back to see how good - or otherwise - it feels.
5) Again if possible (demos are usually offered as a 1 off test) try to get your demo kites for a few sessions on different days. A kite that feels perfect on one day may not be so good the next?
6) If possible test the demo at its upper or lower range. Pretty much any kite will perform nicely in its sweet spot. A kite that is really going to do it for you is going to succeed or fail outside of the 'sweet spot'.
If its the big kite for your quiver test it at its bottom end - if its going to be your small kite test towards the top end. Ensuring there is some x-over between the 2 or 3 kites in your quiver will take care of the other ends.

Set some ground rules in place and work at putting the new gear through its paces - allowing for all the variables that may come into play.
Everyone will tell you 'demo demo demo'. Great advice. But if you want it to really pay off in terms of getting you onto the gear that is really going to suit you then treat it as "TEST time" not "PLAY time".

just sounds like your oversheeting the kite wheels.
Lengthen the back lines or just pull a bit of depower rope. Many proto's are not trimmed right for equal line lengths.