Is it possible to replace the one-piece GSA seat with the two-piece seat found on the normal GS models? The passenger seating area on the one-piece seat is rather small and I'd like to give my girlfriend a bit more room.
I did it years ago and would never go back. There is a (very old) thread here that covers all the parts (with a complete list) you need but basically, you need an 1150 subframe and all the parts attached to it. I collected most of the parts off the Flea Market here and EBay over about a year. I finally lost patience and ordered the rest from A&S BMW. Your passenger will definitely like it better - my daughters find the GS more comfortable than my FJR (I have Corbins on both). They hated the GSA seat. Send me a PM if you need any information.
Why not try a Russell Day Long seat??? I have one I use when touring, it is like a double tractor seat. VERY comfy, I have done 4500kms in 4 days on it with no butt pain at all. It is probably cheaper than buying all the parts to swap over, and you have the choice of switching back at a moments notice. You can see mine at the bottom of the most recent page in my blog, link below.
^^^^This will in the long run be the cheapest route. Unless you really want the ability to use the passenger area for a shelf.
The shelf is nice (I use a Bestrest plate on it) when traveling solo, there is more space underneath the seat for tools etc, and the two seats are about 3-4" longer than the single seat, so there is more room front to back. If you or your pillion are short or lighter than average, the length may not matter to you. Of course, if you are short, the GSA may not be the best bike anyway.... If you do the conversion, your best bet is to find someone parting out an 1100 or 1150 GS and get all the parts together, since buying new is cost prohibitive.
I have the Original 2 piece seat and love it. Riding solo, one seat, riding two up, just slam the back seat on and you ready to go. But you will need the whole chabeng to install this and look original. Seat brackets, tool box with cover, side blends and handle. 2004 GSA 1150 Adventure.
