If it were me I'd record Audio Out of the GR-1 .. not the MIDI
MIDI has no sound, I think you want to record what you hear from the GR-1 as Audio, if I read that correctly
so Audio Out of GR-1 to computer, sounds like you want to record what you hear while playing it
Options - Preferences - Audio
The Drivers button lets you select what RB records .. getting the GR-1 to send Audio to that selected device is the key
Thanks very much rharv for helping out!
Yes you guessed right what I am after.

Using your instructions I am now able to get the synth sounds from my GR-1 into RealBand.
There's just one little problem now.
There is a latency issue. The tracking on my guitar has always been very good. No real
observable delays.
I looked at my notes from years ago and see that I was using an ASIO4ALL driver.
Do you think that might fix the problem?
Or is there another setting to look out for?