My understanding, from a motorcycle enthusiast perspective, is that the term "rice burners" referred to Japanese racing bikes that run on alcohol fuels derived from rice.
Growing up kids called any Japanese car a rice burner because ... Japanese people eat a lot of rice. Yeah there definite racism going on, it's not saki-powered motorcycles.
Customizing appearance, the apparent racist origin of the term is no longer relevant as very few would even know it and even fewer would use it in a racist context
I'm not about to start screaming that xyz is racist, but I would argue that just because very few would know or recognize that something has racist origins that doesn't (in my opinion) make it okay to use. I would hope that people could come up with another term to use that conveys the same message.