  We have studied short-term variations of the blazar OJ 287, suspected to host
a supermassive black hole binary. In this study, we use a two-season optical
R-band dataset from 2004--2006 which consists of 3991 data points from the OJ
287 observation campaign. It has sections of dense time coverage, and is
largely independent from previously published data. We find that this data
confirms the existence of a ~50 day periodic component, presumably related to
the half-period of the innermost stable circular orbit (ISCO) of the primary
black hole. In addition we find several pseudo-periodic components in the 1 to
7 day range, most prominently at 3.5 days, which are likely Lorentz contracted
jet re-emission of the 50 day component. The typical 50 day cycle exhibits a
slow rise of brightness and a rapid dimming before the start of the new cycle.
We explain this as being due to a spiral wave in the accretion disc which feeds
the central black hole in this manner.
