There’s some key info you need to know about Thors:
1. The listed pressures are a bit low – go by sag.
2. When adjusting air pressure, you have to manually balance positive and negative by twisting the travel adjust knob (this connects positive & negative chambers). You need to do this each time you change the positive air pressure.
3. Twisting the travel adjust knob allows a little oil to move from positive to negative, which over time depletes the oil reserve on top of the air piston, leaving you with a notchy fork. It also decreases the negative air volume, which gives a weak negative and exaggerates any top out tendency. To fix this, invert the fork, twist the travel adjust and cycle a few times. I actually leave mine upside down occasionally with the travel adjust clamped open. This little gem is from the Magura technical forum – they’re not exactly going out of their way to broadcast it.
I weigh 154lbs, and I’m running 70psi, if that helps.
They’re a good fork and worth persevering with – I’m very pleased with mine, and it was one of the very first ones (I’ve been running it just under a year).