Remove SUZUKI GSXR-SRAD Seat Unit & Replace with GSXR K Series Back End

The Complete Conversion

Instructions by Dave Nix (Nixey)

I have researched this project and am confident of a good result. (I am an Engineer and am certain it will be as safe and strong as the original bike)

I need to be able to carry a pillion occasionally so I am doing the full K series tail swap.

Items you need to buy are listed below, the prices quoted are what I paid for the parts to do my conversion. You may pay a little more for some items or even less depending on the level of interest on Ebay

I am also going to fit a K 2 seat lock but the SRAD one will do if you canít find a K series lock.

(All the parts are from either a, K1, K2 or K3 GSXR 600 or 750, or parts can come from a K1 or K2 GSXR 1000 but not a K3 1000 because these use a totally different frame)

  1. The first thing is to strip the rear end of you GSXR and remove the SRAD seat sub frame.
  2. Now you will see that the SRAD and K1 sub frames are quite different, the top rail of the sub frame is fine and needs no alterations. It is the bottom sub frame rail that need to be shortened,
  3. Now you need to prepare the K sub frame for cutting; see Figure 1 below.

    Figure 1
  1. When the welds are filed down if you look closely you should see a very faint line where the fixing lug joins the sub frame.
  2. Using a set square mark a line where the fixing lug joins the Sub frame. And mark all the way round both of the sub frames lower legs.
  1. Cut along the line to a depth of about 1.5mm then cut along your next mark until you have cut all the way round the 1st leg. Now the fixing lug should come out and you will have something closely resembling this. Please see figure 2 below.

  2. Figure 2. Use this lug as a template to mark the lines to cut along on the other leg of the sub frame.
    This is the easiest way to ensure both legs end up virtually identical lengths.

  3. Now Cut approximately 13/8 " from each of the lower subframe legs.
  4. The Sub Frame can now be mounted loosely on your SRAD using just the top 2 mountings. You may have to file a little from each top lug to allow the sub frame to clear the main frame.
    Please see Figure 3 below

    Figure 3
  5. Now the subframe is on you have to decide, do you want a Standard look or a Jacked up tail end.
    If you want it to be Standard it is just a matter of fixing the Footrest to the Sub frame and then fasten the exhaust clamp to itís mounting on the foot peg. Please see Figure 4 Below + Note at foot of page.

    Figure 4.
  6. Now I temporarily fitted the 2 lugs, which I had sawn off earlier. I fitted them the wrong way round just to allow me to accurately mark the position of the final cut. Please see Figure 5 Below.

    Figure 5.


    The total amount of material cut from the subframe will be approximately 2 3/8".
    I only cut out 2" because I wanted a slightly taller seat height for comfort.

    My friend has done the conversion on his 600 SRAD (using these instructions) and opted for a more aggressive raised tail look and only cut out 1 3/4"

  7. Now using a Setsquare mark the position of the final cut. Please see Figure 6 Below

    Figure 6.
  8. Once you have marked both sides remove the Sub frame from your bike and take it to a welder and get him or Her to TIG weld it. MAKE SURE IT IS TIG WELDED AND NOT MIG!

    Addendum to step 12

    The K series frames are narrower than the SRAD and although it is ok with the lugs welded on this way round (please see Figure 12 below) spacers would need to be made to bridge the gap between the K series subframe and the SRAD main frame.

    I rotated the lugs by 180°  I don't need spacers because doing it this way they are now a perfect fit.
    (please see Figure 12a below)

Figure 12. The original way the lugs are welded on the lower subframe rails

Figure 12a. The way I have had the lower lugs welded on the lower subframe rails. The K series subframe now mates up to the SRAD main frame perfectly.

  1. Fit the Subframe.

    If you opted for the raised tail look and only cut out 1 3/4" from the lower legs the next step is not necessary.

  2. Now we need to fit the original undertray. This needs a little cutting to allow it to fit correctly, because the Battery box hits the Rear Shock absorber.
  3. Cut the lower front corner off the battery box
    Please see Figure 7 Below

    Figure 7.
  1. Refit the undertray it will now fasten up correctly.
  2. The next step is to secure all the wiring and relays, and the battery. On a non injected SRAD (both 600 and 750s) this is dead easy! The ECU will drop straight into the intended location and be secured with the rubber band. The relays once fastened to the L/H upper subframe rail on the SRAD, are a bit more of a challenge.
    Figure 8 Below will show how they can be mounted On a non injected SRAD (both 600 and 750s) mine is an injected 750 please seen Steps 18 & 19 for a brief explanation of how I did it.

    Figure 8.  (I copied this picture from a post on the original
  3. On Injected SRAD's the ECU is too wide to fit into the tray. It is an easy job to widen the tray by removing a little material from one end of the ECU bay in the OEM undertray. I chose the L/H end (as you sit on the bike) because this means removing less material from the undertray
  4. I could not mount my Relays as in Figure 8 above, because the injected models have a larger ECU so there is not room to mount them as in Figure 8. To get round the problem I cut the original relay-mounting bracket into 3 pieces. I cleaned each one using Cellulose Thinners then applied self adhesive 'Velcro Tape' (Hook and Eye Tape).
    See Figure 9 Below.

    Figure 9.
  5. Relays, starter solenoid and brackets fixed on the undertray as in Figure 10 Below.
    Self-adhesive Velcro is not strong enough to hold the starter relay itís fixed with a 6mm bolt.

    Figure 10.
    For me this was the hardest part of the job. It is important that the relays are held securely and do not hit the seat. The location on the relays above clears the seat and the Velcro seems to hold them securely (except the starter relay).
  6. The seat lock needs to be mounted next, I bought the K series tail lock so it will mount up just as the designer intended
  7. If you need to use the SRAD Seat lock please see the following section on how to do it.
  8. The latch will mount right up. The lock is going to be a small challenge. You can get the one for the new gen bike, but yours will work also.

    Get what is called back strap from your local car stereo store. Get the stiffest ones they have, ones from lock actuator kits work the best. You will not believe how creative we would get with this stuff when I did car audio. Just as for a "back strap" and now one will think you are crazy. You can use a similar material as well.

    While at the stereo shop or at your local hardware store get a "speed clip" and appropriate screw. Slide the clip onto the strap over one hole on the end. This will screw down to the bottom of the trunk and loop around the lock and secure it in place in the hole of the trunk tray. You can try any other method you find this was what I had on hand to accomplish the task. Please see Figure 11 Below

  9. Figure 11.

  10. When you have reached this stage you are almost there! The only other part that needs any real modifications to fit is the fuel tank hinge.
    This is where you need to use the Rivnut inserts and the tool to fix them firmly in place.
    I did not use this method though because it means taking off the fuel tank hinge to remove the battery.
     My method is covered in Step 29

  11. The tank now needs to be mounted. You need to modify the hinge to clear the battery. Cut the mount back with a hacksaw to clear when put in the correct position. Use the two screws at the front of the tank to verify how far back to cut in the hinge. You can see in the photo how I cut it.
  12. The very next step is critical. You must not get this off at all. You will need to put in 8mm by 1.25 threaded inserts for the tank hinge bolts to secure the tank to the subframe.
  13. You need to drill the perfect size hole for these to sit down in. You will need to compress these like a pop rivet. To do this you need the right bolt to thread into this and a larger nut to use as a spacer and appropriate size star washer. Put the bolt into the larger nut and then thread into the insert with the washer against the top flange of the insert. Thread until tight and insert into the hole. Now use a wrench to hold the larger nut and tighten the bolt. The insert should not turn, this is the use of the star washer. It will stop the insert on the larger bolt. Tighten until the insert is fully compressed like a pop rivet. If installed properly the insert will not rotate.
  14. You now need to use the correct tap for the two bolt holes for the seat. Thread into them using the tap to cut into the insert you just installed. You will notice how close together these are. The bolts will hit the inserts when installed for the seat so you need to clear them out. For the tank get bolts just short enough not to obstruct the bolts for the seat and visa versa.

    Figure 12.
  15. I chose not to use the method above to mount the fuel tank hinge for 2 reasons:
    1. Although not a regular occurrence the battery sometimes has to be removed in a hurry and using the method above the fuel tank hinge has to be removed first.
    2. The hinge mounting bolts interfere with the seat fastening threaded inserts
  16. I modified the Original SRAD hinge See Figure 13 below you will see how itís done when you compare it to the standard hinge

    Figure 13. The Battery can be removed and fuel hinge mounting bolts are now well clear of the threaded inserts for fastening the seat.
  17. On an injected SRAD the Regulator will bolt to the sub frame without any problems. The 600ís and non injected 750ís use a smaller regulator and will only line up with 1 of the mounting holes and will need a small ally bracket to hold it securely.
  18. Now all that remains is to fit the tail unit, and Undertray with a Tail tidy and indicators.

    I also need to fabricate a small 1" bracket to mount the exhaust to the foot peg hanger. I need to do this because I jacked up the rear slightly for an easier riding position. (the seat to peg relationship is greater and will not cramp my left leg so much)

The rear looks tons better than the old. (Junking the rear light and crap undertray are the next jobs)

My Mates bike (converted using these instructions) with a slightly raised tail end. It looks even better in the Metal
Note: The silencers are not clamped in these pictures.

Raising the rear end like this means a small bracket needs to be made to join the exhaust strap to the mounting point on the right foot peg hanger.

The owner of the bike pictured above did not do this he preferred to have his exhaust link pipe bent up slightly. It looks better done like that but a link bracket is easier.

Tools you will need:

Threaded inserts: 
I used 6mm Inserts to fasten the fuel tank hinge

The Rivnut fixing tool showing threaded inserts and Nose pieces e.g. For a 5mm Rivnut you need the 5mm threaded Nose piece.


The Insert is Screwed on to the Mandrill of the Nutsert tool


The Insert is then pushed into the correct hole in the Top rail of the subframe
  Squeezing the Handles of the Nutsert tool forms a bulge in the Insert which holds it firmly in place
Unscrew the Nutsert Mandrill from the insert using the 'Knurled knob' at the back of the tool
  Fasten the Fuel tank hinge and that's it.
This method can be used in virtually any situation where you cannot get to the back of the job to put a nut on.

I borrow one from a friend but they are readily available on ebay.

They are real easy to use and produce a professional finish. All of the bike manufacturers use them .


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