Yamaha 1300 Tourer - Yamaha 1300 Tourer Fansite

I just bought a Garmin GPS. My question is for anyone storing mp3's on it. How many songs can you load on it without using a memory chip and how many with a memory chip? I've searched the owners manual I downloaded and it doesn't say. I know the memory chip offered by them is only 512mb and I can figure from that how many mp3's I can put on the chip. Can it use a bigger one? The manual is about useless.

Thanks, Hutch