We have obtained simultaneous photometric and spectroscopic observations of the cataclysmic variable 1RXS J064434.5+334451 .
We have calibrated the spectra for slit losses using the simultaneous photometry allowing to construct reliable Doppler images from H \alpha and He ii 4686 Å emission lines .
We have improved the ephemeris of the object based on new photometric eclipse timings , obtaining HJD = 2453403.759533 + 0.26937446 E .
Some eclipses present a clear internal structure which we attribute to a central He ii emission region surrounding the white dwarf , a finding supported by the Doppler tomography .
This indicates that the system has a large inclination angle i = 78 \pm 2 ^ { \circ } .
We have also analyzed the radial velocity curve from the emission lines to measure its semi–amplitude , K _ { 1 } , from H \alpha and He ii 4686 and derive the masses of the components : M _ { 1 } = 0.82 \pm 0.06 M _ { \odot } , M _ { 2 } = 0.78 \pm 0.04 M _ { \odot } and their separation a = 2.01 \pm 0.06 R _ { \odot } .
The Doppler tomography and other observed features in this nova-like system strongly suggests that this is a SW Sex-type system .