Having a bassline in place makes it easy to turn the groove into a funk riff. While the rhythm section in a funk band creates the foundation of a groove, guitars, keyboards or horn players usually play just short attacks – chords or melody notes – to give the tune its characteristic style.
The secret here is to spread the different instruments across the beat. Whereas in rock or blues music most instruments play together in layers over the beat, in funk they are disparate and play only certain accents together.
With that in mind, a good way to add the right hand to the left-hand bassline is playing in the spaces of the groove. The only accent with both hands together is on the 1 and of each bar plus the 3 of bar 4.
C7#9 with the root C, the 3rd E, the minor 7th Bb and the sharp 9th Eb (or D#)
Again, adding drums lets the riff come alive even more!