XRAY - Model racing cars

you mean it moves accros the pulleys from left to right?

the only thing i can think it catching on is the servo saver/servo saver post

Can that be right?

I have ran about 60-70 packs through my FK and the belt is at least 45° between the pulleys. But it doesnt slip nor does it look worn.

I actually had too loosen the setting because the belt got tighter after a few runs And no, there are no dirt in the pulleys, I allways keep them 100% clean. All screw are tight too, I check them after 4-5 packs.

That's new to me, the belt tightening that is. You may want to lubricate it with WD40 as it may be drying out.

As to the angle, the reason I recommend replacing the belt at this stage is that you now run the risk of the belt flopping over altogether at the front pulley. When this happens you suddenly only have rear wheel drive which the car is definitely not designed for . Granted, the risk is low and usually needs a crash or hard hit on the kerbs for the belt to flip over, but it does happen. And as Murphy's 2nd law indicates when things can go wrong they will do so at the worst possible time (A-main, leading with one lap to go... ).