This main riff starts after the high, delay-soaked intro chords and the short, fast fill that follows them. It's quite a challenging riff and you need to be on top of your game to play the part cleanly.
The riff is based on a single rhythm that's repeated using different notes. Use alternate picking throughout and try to minimise your pick motion. Keeping your pick tight to the strings helps you get the riff up to speed.
Rope involves a lot of quick fret hand position shifts, too, so don't linger on the final note of each section. Mentally prepare for each shift while you're still playing the preceding part. Memorising the melody before you start playing will help you anticipate the changes and make them more fluent.
If you struggle with the fast six note phrase at the end of the riff, try playing the F and E notes with your fourth and third fingers. This leaves your other fingers in prime position.
Get the sound
The riff in Rope uses quite a thick tone to contrast the high chordal parts, so boost the bass a little and cut the treble a tiny amount. Avoid using too much gain: a fast, precise riff like this will quickly turn to mush with a high-gain tone. Opt for the neck pickup to give you the thickest, warmest tone.