I was wondering whether it would be possible to use second term? I know first term is correct but does it mean the second one is not correct?
Maybe I will go and race in something else
This sentence is generally correct. In almost all situations this is what you would use.
Maybe I go and race in something else
This is for when you are talking about a hypothetical case, while removing the emphasis on your own actions. Think about a mafia boss making vague threats:
It's fine if you don't pay your protection money. But maybe I find myself in need of funds one day, what will I do then?
As a general rule though, you need the modal verb in your first sentence.