Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Where are the speakers for the XM radio function? I was wanting this unit for a motorcycle. I have handle bar speakers now.
Document: You can add your own points of interest which I have had to do a lot....this area is growing so rapidly that many things are missing from the database. The traffic function of the XM radio is fantastic, unfortunately the coverage is very limited. Only 2 roads in my county have any coverage and it is only a few miles of each.I love the MP3 player, and the remote is extremely handy. The XM radio is not nearly as full-featured as my old unit.
I had been searching the various GPS manufacturers for awhile before settling on the 2730. I recently took a motorcycle trip to Wyoming from NY and had this GPS mounted on the handlebars. Very well made unit that made my trip much more enjoyable. I purchased this particular unit over others by TomTom and Garmin because I liked the XM weather/traffic/radio combination more than the bluetooth capability of the 'rider' and the 2820 (although the 2820 offers XM also, it does not supply the antenna as the 2730 does).
Well working product that gives clear directions. Remote removes the need to reach for the unit and take your eyes off the road; remote is most useful for volumn and (re)speak functions. The FM transmit-audio-to-your-radio function doesn't work in most medium or large size cities, so don't count on it. An audio input jack to your car radio is a must if you plan to use it to listen to XM radio.
The 2730 design is perfect for use on my motorcycle. I mount the GPS on my bike using a mounting system from Ram. With the GPS, MP3, and the XM radio it provides a single source for navigation, and music directly to my helmet using only one wire. I upgraded from the 2610, and the screen quality is much better with the 2730. I also like the fact that the streets are mentioned by name. This helps when you have two or more streets really close to each other.
On the DC reroute, it saved about 3 hours just with the reroute.I also opted for the XM radio function, and this also works very well. I plugged the XM music output into the stereo on my car, and it played XM on the stereo.As a GPS navigation system, it works very well. I found that it calculated the routes much faster than my streetpilot III, literally in seconds.
The stations loose signal, and the sound quality is not very good. When the XM radio is hooked up with a wire the sound quality is fine. Unfortunately my Ford F-250 does not have a place to plug the 2730 into the factory FM radio.The Mapsource software need to be more user friendly. One thing that we do a lot on motorcycle trips is plan a route at home on the computer then download it into the GPS. This can be challenging with the current software.
I bought the Street Pilot 2730 for it's ability to function as a GPS, satellite radio and MP3 player. I will have to say that the 3-D graphics are great and it seems for the most part to have up to date information on the routes, but after adding a half MB of MP3s, the system totally shut down and nothing would work until I removed them.
The voice recognition software is a nice new touch (though I think "Dr" should be read "Drive" not "Doctor"). I haven't got an XM subscription yet (the traffic function isn't in my market anyway), but I have tried and love both the audio book and mp3 functions. One advantage of being in a smaller market is the availability of signal-free FM frequencies for the FM transmitter.
I screen fogs up when I use it on the bike. I have returned one unit to Amazon, and the second one fogged up also. Great service from Amazon by the way. I contacted Garmin customer service, and they told me that the 2730 is made for use on a motorcycle, and should not fog up. I hope they are right, because this model is perfect for what I use it for.
I bought a Street Pilot 2720 ~5 years ago and found the more I used it, the more I used it, on the motorcycle and in the car. When I saw a factory refurbed unit available for about what the nuvi's go for, I jumped on it because the big drawback to the 2720 was no music. The 2730 gives me my music AND GPS info on the road. (I don't need or want bluetooth capability as in the 2820.
Answer: The SP2730 has a stereo "audio out" female jack (I think it's a mini-size) on the lhs of the unit.  It's covered with a flexible /rubberized plug to keep the unit water-tight when the jack is not in use. If your present audio source for your handlebar speakers has an "audio in" plug, simply hard connect the SP2730 to your present source.  I connected the audio out on the SP to my Cardo unit so I could get the SP output (GPS directions/music)in to my helmet speakers of the Cardo unit when I used the 2730 on the bike.  Since the power for the 2730 comes from the cigar-lighter/speaker combo that comes in the package,  you'll also need the MC power adapter power kit(wires) to hook up to your bike to run the 2730 on the road. I still use the 2730 in the old car I drive, but memory size of the 2730 is not big enough to load all the US from MapSource--I have to select the part of the US (about half) I use it in.  Old is not bad--it does have limitations though.  Good Luck & ride safely.