Under the hood where the drive line goes in, there's an L shape gear box. Look down on the bottom roller shaft and you'll see two round plates bolted together(on short drive shaft) with slots in them. I think there's carriage head 3 bolts. You can loosen those bolts and advance or ****** the bottom roller to make the treads fit between the treads on the top roll. There should be an even spacing between those treads.
I ran a 1217 for 15 years and I'm pretty sure the 1207 is the same.
Also after you get those rollers timed, start the machine up. If it's rumbling loud the rollers may be to close together. The adj. rods and nuts for that is on top near the reel. One on each side. If I remember correct you lower the roller until you hear the noise start to get louder from the contact between the rollers. Then back it away so many turns per the manual you have. Can't remember how many turns(think it's 1 and 3/4, could be wrong). Those nuts are nylon locking and stay where you leave them.
The pressure setting is under the hoods on both sides. There's a threaded rod with jam nuts on it. Your machine may be a little different but I know I helped set up a 1209 and it was the same as the 1217.
Hope this helped. If it didn't I may be able to take some picture of a 1209 in those adj. locations.
