Can you still buy a rear seat support [backrest] and saddle bags for a [double seat] for a 1999 1500 Kawasaki Drifter and where? I am in Brisbane, QLD, Australia.

Rear seat cushion-fold forwards,release plastic clip from hinge,remove wiring multiplug if applicable.Lift out cushion.(40% backrest)Tilt forward approx 20degrees,use a screwdriver to release catch retainer on outer pivot pin.lift backrest and withdraw from inner pivot pin.Lift the backrest from inside vehicle.(will only lift out if backrest is tilted forward 20degrees from verticle. 60% section can then be removed on saloons by releasing the lock with a finger and pulling from the anchor pins.On estates unscrew centre seat belt lower mounting and unscrew hinge pin from centre support. unhook upholstery clip and lift backrest from lefthand side mounting.slide backrest towards the door to release centre pinlug and withdraw backrest from inside the vehicle. Refit in reverse order.

Do not bend the rear seat back rests, they will never be the same again. On most (if not all) cars the rear backrests are bolted on by means of two bolts behind the seat, so first remove the seat (the bottom padding that keeps your backside from hitting the floor) by pulling the seat up. On some vehicles, the seat is bolted down with two 6mm bolts on either side. Once you have the seat out, you should see two bolts holding the back rest to the body of the car. Undo these, and the backrest comes off easily.
Now fit the seat covers and bolt the backrest back into place. It is not a difficult job, shouldn't take more than an hour or less.

There is one screw through the tab on the back of the seat to the rear fender that needs to be removed.
Additionally, if you have the grab strap between front and rear passenger seat, you need to either unbolt one end of it (the same bolt holds on the front saddle bag mount) and thread the strap through the slots in the seat, or unbolt on both sides of the strap.

Lift back of seat slightly, and pull seat to the rear to remove.

Normally one bolt in the back and the pillion slides into the driver seat. Pulling back on the pillion after removal of the hold down bolt usually releases it

A bolt is underneth the driver seat at rear. Hard to see. Maybe pull off driver seat first the rear seat - be sure you are using a soft saddlebag
support. Don't get bags caught in wheel

Two bolts on the rear fender will need to be removed.
Also remove the passenger Pillion(Seat). Normally one bolt in the back and the pillion slides into the driver seat. Pulling back on the pillion after removal of the hold down bolt usually releases it.

The brackets to hold the saddlebags straight and away from the rear tire/ brake disc. Mounts with shims to the two bolt holes on either side of the bike. (remember those bolts removed earlier?) Center the saddle bags by eye. Sometimes it is best to have someone hold the bike straight and center from the rear. If the bike is on the kick stand, it will not be easy to center the saddle bags.

Next put the passenger pillion back in place.
Check the bracket clearance and make sure no part of the saddle bags are touching any moving part. You can bend the brackets to adjust but usually not necessary. Just be careful with the chrome fender flares.
Those curved chrome rear fender shiny things. :)
You can scratch the paint very easily while working with them.
Use a cloth/towel where you can to prevent marring of the paint.
Really simple to do with minimal tools. Some of the saddle bag bracket kits come with longer bolts. Use them!

My 1100 Vstar I used the twist rods from a set of Shoe Stretchers.
Screwed directly into a kuryakyn foot peg adapter. Black with a triangular tip worked great. Heck of a lot cheaper too!
Nice thing about this arrangement, only had to remove the foot peg bolts. Then the rear passenger seat. Easy to adjust the angle of the bracket by loosening the foot peg either side. Pull up, push down or bend out to get proper position.

Good luck!
Hope this helps!

I think you have to remove headrst bfore folding seat back down. You may have to unbolt seat from floor. 4 bolts.
Rear Seat Backrest —Split Bench Removal
NOTE: The 40% rear seat backrest must be removed before the 60% rear seat backrest.
40% rear seat backrest

1. Remove the 40% rear seat backrest.
   1. Remove the nuts and bolts.
   1. Remove the backrest.

60% rear seat backrest

1. Remove the 60% rear seat backrest.
   1. Remove the nut and bolt.
   1. Remove the backrest.

Installation
NOTE: The 60% rear seat backrest must be installed before the 40% rear seat backrest.
60% rear seat backrest

1. NOTE: Do not tighten the nut and bolt at this time.
   Install the 60% rear seat backrest.
   1. Install the rear seat backrest.
   1. Install the nut and bolt.

40% rear seat backrest

1. NOTE: Do not tighten the nuts and bolts at this time.
   Install the 40% rear seat backrest.
   1. Install the rear seat backrest.
   1. Install the nuts and bolts.

60/40% rear seat backrest

1. Tighten the 60/40% rear seat backrest nuts and bolts in the sequence shown.

40% Rear Seat Backrest

1. Tighten the 40% rear seat backrest nuts and bolts in the sequence shown.

The rear seats have a pull strap located between the bottom cushion and the backrest of the rear seats used to disengage a lock to lift up the bottom cushion. The pull straps will only stick out an inch or so, or they might have fallen down between the seats and then you wont see them. Before you can lower the backrest of the rear seats, the bottom cushions have to be lifted up and forward out of the way so that the backrest may lie down flat. If your pull straps are not visible between the bottom cushion and the backrest, you may have to stick your hand between the cushions and feel for the straps. Once you find the straps, pull upward on the while lifting on the bottom cushion where the pull strap is located and the seat should tilt forward. Once you have manged to do this, the lever for the backrest is located on the top of the backrest. Just slide the lever and tilt the backrest to the desired position.

The strap that goes around the seat bolts to the fender under the fender it's self or to the sides near the front of the fender struts or behind the saddle bags if you have them.
They are usually held on by either an allen bolt or a capped hex bolt.
If it is attached under the seat it is held by 1 bolt through both ends to 1 hole.