2006 Gs500 No compression on right cylinder

[Valiin]

Hey guys I have a 2007 gs500 that I've rebuilt with a 2006 motor. It runs but it is sluggish as all hell, backfires, and worst of all, it's only running on one cylinder. Compression check on the right side showed 0psi. What could be the cause of it? I don't hear any alarming noises coming from it, other than the popping and choppy idle. Not sure where to check or if it's even something I could fic myself

[Big Rich]

Most likely...... your valves are way out of spec. WAY out.