Be gentle, i'm new here ok?

I have Rock Shox Tora 318 on my Bike. You can alter the ride height,the rebound, and the damping?

what is the best set up for down hill on single track?

I'm assuming the forks should be set to max travel, but what about the other 2 settings? should i have a harder suspension or softer? what about the rebound and damping? I'm confused.

I'm trying to improve my technique, and hopefully speed along with it.

What model are they?

Toras are coil sprung, so you can't alter the sag or spring rate without changing spring. I'm guessing there is preload, which if you increase it will make the fork feel more stiffly sprung (but actually this only alters the force needed to get the fork working at all – I'd leave it on the soft or nil end).

I think they have rebound damping adjust – start somehwere on the + end (ie slower rebound damping) not so slow that they pack down on successive hits.

Ride height (are they U-Turn?) I would experiment with until you get the steering feel you like – higher for slower steering, lower for fast.

Its these ones: http://www.bikemagic.com/news/article/mps/uan/4480

The black ones that are air sprung.

OK. Air spring means you can change the sag, which is good.

First set the travel to what your frame is designed for (100mm?).

Then add to take out air to the point that when you sit in your normal position on the bike the forks sags by about 30%. Having someone to help makes this easier, because it is easy to accidentally bob the suspension as you get on and off. Use a zip tie on the stanction to reveal how much travel you have used.

Then set the rebound on the slow-ish side. Try riding down some shallow steps to get a feel for rebound – the fork should feel the same on each step and not get progressively firmer, which would be a sign that it wasn't bouncing back with each hit. Neither should it feel overly bouncy though.

Do all of the above with the compression damping control set to minimum. After you have the fork set up you might want to use the compression damping to help control the tendency for the fork to bob when you are pedalling – personally I think it is better to adapt your pedalling style to not bob the fork anyway.

Finally (!) I'd say once you've got the setting about right leave it alone and get plenty of riding done. Further adjustments can be made with the benefit of riding experience, without the experience you'll just be fiddling without purpose and blaming the fork for everything!

I'd start by setting the air pressure + & – to what Rock Shox recommends for your weight.

Then twiddle your rebound knob (probably the red one on the bottom of the leg) and see how many twiddles it is from one end to the other. I'd then set this in the middle.
I am not sure how adjustable the compression damping is or if RShox give you guidelines, but if not I would set it in the middle of it's range again.

The rebound damping changes how quickly the fork extends back to full length after being compressed. If it's too fast, the air spring will kick back and feel bouncy. If it's too slow the fork won't extend quick enough to absorb the next bump. On repeated bumps this will make the fork lose travel (or pack down) as it keeps getting shortened & not given time to return.
Ideally you want the fork to rebound quick enough that it doesn't pack down, but not too quick that you can feel it springing back up and pushing you with it.

I am not too shure about compression damping, but I think it's basically the opposite of rebound damping, in that it damps the movement of the fork as it compresses. I think if you run a lot of compression damping, the fork feels more 'locked out'and it takes a bigger impact to get it moving.

Set it to around 30% sag for trail riding, so wound out to 130mm travel, sit on the bike normally and measure how much travel your body weight takes up. For 30% you're looking at about 39mm – add more air if it's in the 40's or take air out if it's in the low 30's. Next set the rebound so that as you bounce the suspension (stood next to bike) you can just get the wheel off the floor before it rebounds all the way back. Play either side of here for your preferences, but on a hardtail I prefer it slightly slower than most people. For compression go as fast as you can without causing too much problems with brake dive. Slower compression means you'll get less brake dive, but less bump absorbtion and grip as the wheel won't follow the ground quite so well. So start at the fast end and come in a click or two depending on how it feels on the trails you ride. Steep, steppy trails are good for the slow compression so the forks doesn't dive and have you over the bars, but for most UK stuff you're better off with it at the faster end of adjustment.

Thanks all….. I think I get it.