I believe I know exactly what your cause is. Did you buy one of those top end rebuild kits off of eBay or Amazon. I've installed 2 of these recently and had the exact same noise you have. One was worse than the other. All the parts were within Honda's tolerance. However, when I measured the Piston in a spot that wasn't specified but compared to an oem Piston it was out by 0.018. I went ahead and changed the Pistons in them and the noise completely went away. That's the only variable I changed. Those parts look great and the cylinder jug is great for the money, but for some reason the Piston specs are crap. Also the hole for the wrist pin was lower than the oem. Piston slap was causing the noise.