Dear Bear West,
You have some options here...and since you do not want to chance losing his friendship, then perhaps not a direct conversation, not right now.
But for yourself, just know that if he did reject you altogether because of homophobia, then in the long run you have not lost much. Meanwhile, perhaps discuss with him some news items about current gay issues...
Once you know more about his approach to sexuality, you can then discern whether there might be potential for a romantic interest with you.