Changing my field after having started my project for my thesis I am about a month off of starting my Honors year at university (essentially an extra undergrad year aimed at getting students ready for research) and since I was very eager to get into research, I went around my department 6 months ago asking for a supervisor and found a project joint by 2 professors whom I respect and are very strong in their respective fields. After spending the past few months bogged down in my classes I finally got around to researching the project only to find that while I thought I enjoyed the field I find it bland and uninteresting which has made me a bit depressed at the prospect of having to commit to this for a whole year after next month. As a result over the past few days I have been thinking of swapping to another field which I believe is more 'meaty' and that I would enjoy more (I am already on good terms with a supervisor for that field) but at the same time I don't know if it is a sort of academic suicide for me to drop this project and build bad blood between my previous supervisors as I respect them and have nothing personal against them (will it reflect badly on me for not having researched their fields well enough beforehand?). Essentially, is it possible for me to swap fields to something I actually enjoy while staying on good terms with everyone?
I spent half a year working on something which I did not enjoy and had no expertise in because of making the same mistake. It's not as bad as it sounds. Sure, it's not nice, but half a year or a year is a manageable time and doing this could also be a good learning opportunity. Still, it would of course be better if you could change of course.

To what extent did you discuss the original idea with those two professors? Do they count on you, have administrative loops been taken? If you have only talked on general terms about possible opportunities, it would probably be OK if you back out politely. They will understand that an undergrad can change his interests.

However, I would make sure that you are sure of another project before you discuss it with the old professors. You don't want to be in the situation that you cannot find a new project and have to return to the old project, because they will feel 2nd choice. So, I would advise you discuss this first with the professor where you want to do your new project. Explain the situation, be open, and ask him for advice.