If you're talking about the FT-8900 it can't be made to do CB. It will demod AM for air band receive but even completely opened it will only transmit 28-30MHz and 50-54MHz and it's an FM-only modulator.
You can make the VX-7R do wide band transmit but it will only do AM on 40-75.995MHz, which is I think a byproduct of the guts being packaged for aircraft radio. It won't transmit AM on 11m and in my experience its HF and very low band VHF isn't great anyway.
Are you thinking of something else, perhaps there's a Chinese quad band that I'm not familiar with?
The only radios that can be modified to do CB are 10m and 12m HF rigs. I'm not thinking of any quad band VHF/UHF radios that could do it. As for either being a ham radio, neither can demod or modulate SSB, just DSB AM, so they're not terribly useful. Very little of ham phone is done double sideband full carrier, it's almost always single sideband, suppressed carrier.
BTW, the FT-8900 being a 10m radio is cool and all, but to access the FM part of the 10m band you need to be a General.