Is your chain line correct, that is, are the chainwheel and cog correctly aligned with each other and with the chain? Do they rotate without wobble or excess eccentricity on their own? Is the chain the correct width for the other components and closed correctly without any tight links? Is the chainwheel correctly and securely attached to the crank, and the cog and freewheel to the rear hub? Bottom bracket and freewheel turning freely without excess play or binding?

In troubleshooting one generally looks first at the last thing changed. Since you have upgraded the whole system you should probably take a step back end ensure that each individual component is suitable for the system and correctly installed.