I am a second year PhD student currently working on three papers mostly unrelated to my field from previous research appointments (2 from rotations and one from undergrad). I'm finding myself very unmotivated to complete these simply because I'm not sure how beneficial it will be for me to publish them. I don't currently have any publications, but I'm currently working on a project in my lab that will hopefully get me a pub within the next year. Should I drop responsibility/authorship from these publications entirely, decrease my responsibility on the paper (currently first or co-author on all of them), or stick it out and publish them? I'm most worried about if it will hurt my reputation later to have a bunch of pubs during my grad school years that are completely unrelated to my thesis.
I struggle to see how having papers outside of your PhD field could be a negative - demonstrating you have knowledge, interest and expertise in a range of subjects can be a bonus. But as mentioned above, they must be of a standard you are happy to publish. Your PhD thesis (plus papers published along the way) will show your expertise in your main field, so why not show off your other skills too?
Plus, I imagine a lot of time and money has been invested into your previous work. I think you should use that for the benefit of your co-authors as well as yourself. But if you find the extra work is having a negative impact on your current studies, prioritise what is right for you.