To me the main riff (A-G-E) sounds and feels like 3/4. I try to tap 4/4 to it and can't play it on guitar. The opening riff (the slide from F-G) doesn't sound like 4/4 to me, either, but I can't figure out what it is. The rest I can count in 4/4, though it doesn't "feel" exactly right to me not sure why.
LOL 4/4. If there is something weird in there I'm not hearing it. You can steady tap 1-2-3-4 easily through the whole thing. Well, I can. You obviously can't. Keep trying. A lot of things happen on the "ands" and turned around beats. Don't let it throw you off.
Great energy in this song. It's all 4/4. No 3/4, but a few reasons the time signature sounds more complicated than it is.
1. Beat anticipation. The A-G-E riff anticipates beat 1 by starting on the & of 4 of the previous measure. This is a common figure in pop and rock music. Usually it doesn't bother us. In this song, combined with #2 and #5, below, it gives us the impression of 7/8 time when the riff starts.
2. Chord progressions we're used to hearing on certain beats. For example, the E of the A-G-E riff is on 3. We're used to it being on 1. Plus, see #1 above.
3. Rhythms we're used to hearing on certain beats. For example, in verse Riff A, the A-A with the snare drum is on 2,3. We're more comfortable with it on 4,1.
4. Inconsistent phrase lengths. The verses have 3-bar phrases, then a 4-bar phrase. The post-chorus is a 6-bar phrase. Other phrases are 2, 4, 8 bars.
5. Fast tempo. It all happens quickly so it's hard to process when unexpected things happen.
6. All-around rowdiness.
Contrary to what was previously suggested, the count off is 1,2,3, with the entrance (pickup notes) on the & of 3, and & of 4.
For programming, you may find it useful to use a transcribing program to slowdown and repeat sections of the song. You may find free ones, but this is the best I've found and I use it for my professional transcribing jobs: SeventhString Transcribe!
How Does A Non-Drummer Figure Out A Time Signature
It's been suggested already: count along. For this song, it helps to tap your foot. The key is to count at a consistent rate; don't count some numbers slow and others fast. At the beginning of the riff, start counting from 1. When the riff feels like it's restarting, start over at 1. It may take a few attempts, but eventually you should get it. There's more than one right answer. For this song, I agree that 4/4 is the most reasonable time signature, but every music can be written more than one way. This song could be written as 2/2 or 8/8 with identical notation as the 4/4 at 186 bpm. It could also be written as 4/4 at 93 bpm, in which case note values would be halved, so you'd write 16th notes instead of 8ths, and 32nd notes instead of 16ths. There would be half as many measures in the song. The 3-bar phrases referenced above would be written as one bar of 6/4, or a bar of 4/4 followed by a bar of 2/4, or 3 bars of 2/4.