Can I to quantize the notes by triplets in Yamaha MOXF6?

Yes, you can. The Clock pulses break down as follows:
Smallest to the largest quantize values
32nd note, 16th note triplet, 16th note, 8th note triplet, 8th note, 1/4 note triplet, 1/4 note

You are additionally given two that are used to tighten up a groove that features both straight and triplet notes:
16th note + 16th note triplet, 8th note + 8th note triplet

There are 480 clock pulses per quarter note
240 = eighth note
120 = sixteenth note
60 = thirty-second note

320 = quarter note triplet
160 = eighth nite triplet
80 = sixteenth note triplet

Thank you very much, BM!