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Pictorial - Katana Swingarm mod to fit GSXR Wheel.

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  • Pictorial - Katana Swingarm mod to fit GSXR Wheel.

    Here is the first part of the modification with pictures I promised.

    First, here is the 90 600 Kat frame I used as my mock up bike. I used it since I am planning to also change the tail on my 750 Kat.

    The is the swingarm prior to modification. It is a Pre 750 swingarm. You will noticed center lines and parallel lines marked out on it for our measurments and cuts.

    Here we are starting the first cut using a hand held band saw. We were initially just going to use this swingarm as a practice run to see what we were getting into. It ended up coming out so well, it's going to be used as the real thing.

    Second cut to complete removing a wedge shaped piece from the arm.

    Here you can see the wedge removed. Going forward doing this again, we would make a slight change here. We started off 90 and did our angle from there. Next time we'll make sure the cuts made split the difference in the angle, so that 90 is center of the wedge. This will make the cut edges closer in size to each other and make cleaner welds when put back together.

    Here you can see we are cleaning up the cuts just a bit, and adjust the angle slightly. No flash, so the pic is a bit yellow.

    After the clean up, we close the wedge to see how everything lines up. This cut is ready to be tack welded to temporarily hold it in place.

    Wedge cut number two. Here the angle cut is done oposite of the first one to bring it back to form.

    This is closing up the second cut and it's now ready to tack weld to hold in place.

    Starting the cuts on the second arm. It's done exactly the same as on the first one.

    Fully cut and tacked back together, we temporarily mount the wheel up to see how it's going to work. We knew the old axle was not going to be long enough to use, so I already had a new one made. Here we have used both the old axle and new axle so that we have handles to push and pull the wheel in the slots to take measurements with. You might notice, no spacers yet. This is just a quick check to make sure the wheel will fit in.

    More pictures for clearance aspects. This shortened the overall length of the swingarm by .75" and widened the swingarm at the axle by 1.5". This means I will need to make all new spacers for the wheel and swingarm mounting. We were pretty sure on the distance we would get for the axle but I had some give on it as well in the length of threading I ordered on it. The spacers have to be more exact, so they are delayed until the arm is fully welded together.

    Here is a picture of just the swingarm to get an idea of it's new geometry. Not welded up yet, still just tacked together.

    So the welder takes the swingarm to his shop, straps it down on a flat plate and welds it with stainless (he says this will make the weld stronger without leaching much carbon). Checks to make sure it's square and everything turns out perfect. Brings it back and we mount it up on the mock up bike. Here the arm is down low.

    Here we move it up some towards the tail.

    Here are some different angles of it on the bike without the tail or subframe modification done.

    The brake arm is not mounted yet here.

    Notice the chain still lines up right using the stock GSXR spacer between the wheel and swingarm on the chain side. No need for me to offset the front sprocket.

    I attempted to modifiy the original brake arm the same way, but that didn't work out well. It still is too close to the tire, and the arm is too short with what little I did do. Can't use it.

    So, started from scratch and made a new brake arm. Here it is in progress.

    Here is the new brake arm with the welds cleaned up and sanded, ready for prime and paint.

    Swingarm is now cleaned up around the welds and sanded down ready for paint. Initial paint job will be a spray on black gloss so I can see how I like the color. Will eventually have powdercoat but that will be done with all the other parts at once time when I have completed all the major modifications and I'm ready to tear down the frame as well.

    Now that the swingarm is welded I mounted up the tire and worked out the spacers I needed. I used a piece of PVC plastic pipe and cut test spacers out. Using that I was able to make sure my measurements would be correct before giving them to the machinist. For any special shapes, I provided the old spacers for reference.

    Here is the new spacers I need. The long one was made for inside the GSXR wheel to have the correct lenth and ID. It's to space the bearings correctly when mounted. The Bearings used in the GSXR wheel are from a Katana rear wheel. They all have the correct OD to mount right in. The center spacer had to be made new though, because the GSXR wheel is wider than the Kat and has a larger ID.

    Another angle for the spacers. From left to right, the first one is the spacer for the brake arm. Next is the Spacer for the wheel chain side. Then a small spacer between the brake arm and swingarm to make it all fit tightly.

    In this Final picture you can see some of the other hardware and bearings I was able to recycle or use without having new made. Top side of this are the parts from the swingarm. Long sleave goes in the center, with the two smaller ones on either side to seat with the needle bearings. The two end caps are then placed to hold them all in. The large rubber piece is the swingarm chain protector/guide to prevent the chain from rubbing the swingarm.

    Bottom side you see the 3 bearings for the wheel, and the 2 dust covers that help to keep them clean. The spacer in the middle goes inside the carrier. These are all stock katana parts.

    I'll follow this up with more pics once the paint is on and dry to see a more finialized product. Once assembled this will be a direct bolt on and go setup for any Pre- Kat I want, with the exception of adjusting length of chain.

    Before mounting this up, I still need/want to modify the subframe and tail of the bike this is going on, get a new sprocket and chain set, and do an exhaust modification as well.

    *** Edited to add more info 02-15-09 ****

    After looking again at the swingarm on the mock up bike, we decided on a slight change in needs to finish the modification and mounting process for the swingarm. Clearance was really not an issue as much as we thought it would be. Changing the stock pipes 4 -2 out for a Vance and Hines complete system 4 - 1 resolved the largest clearance problem. So we decided to delay the tail swap for this, and see if we could mount this modification into a stock tail.

    I did not get pictures of the parts post paint before assembly. I forgot the camera and we went forward with putting stuff on.

    The mounting process was pretty simple on the 750. Set it up on the centerstand and took both rear side panels off the tail of the bike. Removed the lower belly fairings, and dropped the old exhaust out. Removed the covers for the swingarm pivot bolt. Removed the rear tire. Unbolted the shock at the top, unbolted the dogbone at the frame on bottom, and then unbolted the swingarm pivot bolt and pulled the whole assembly out.

    With the old swingarm removed we then swapped out the links, dogbone, and shock to the new swingarm. We then began the re-install process.

    Bolt for the swingarm pivot first, then the upper shock mount, then the lower dogbone mount to the frame. Torqued everything down as needed, and the new swingarm was all mounted in. Installed the new brake caliper arm, and then mounted up the new wheel with all the hardware pictured above, and the newly modified chain adjusters.

    At this point we confirmed the chain was 4 links too long for the sprockets currently mounted. This is due to 2 factors. First, the swingarm is now shorter by 3/4". This pretty closely works out to 2 links alone. Second, the sprocket that came with the GSXR wheel is a 46 tooth, one less tooth than the stock Katana sprocket. This drops another link. Finally, the chain is older and stretched some... so we rounded down in chain links. So we cut out 5 links and put back in a master link. (*** Note: New chain and sprockets will be ordered almost imediately for the final of the modification. The current chain is only be used to verify what we are doing is going to work. ***)

    After mounting up the chain we adjusted the rear wheel and chain and tightened up the axle bolt. Swingarm and wheel all mounted.

    Now, to check for any clearance issues.

    Since we started with a stock size swingarm everything behind our first cut was still stock sized and no clearance issues at all there. We only needed to look at the area near where the exhaust mounts, and the clearance for the wheel it's self. Using a large bar we bent the passenger footpegs away from the bike a bit, probably a bit too much but we can always bend them back down a little. After taking the bike off the centerstand and 2 rather large men bouncing on the back of the bike... it was pretty clear we did not have clearance issues for the swingarm at this point. I really wish I had a picture of that test...

    On to mount the new exhaust ( this was an excersize in frustration, and probably one of the longest single steps of the entire process. Some bolts just did not want to start... ) The factory dual pipe system had the pipes barely clearing the stock swingarm leaving no room for the wider one. The V&H system allowed for alot more room and was fairly flexable in placement without having to bend anything.

    We then re-installed all of the plastic for the tail and lower fairings.

    Time to double check everything was correctly set up, pump the brakes to make sure they are working properly, and a really short few trips around the parking lot and driveway. At the very first the rear sprocket was picking at the chain once in a while. Mainly we realized because the chain and sprockets are worn slightly differently (both used from different bikes) but it was not an alignment problem. Lubed the chain and it reduced that alot.

    Last step was a lower speed test road test down the road a bit. 15 minute ride at 35 or less speeds. Everything seating in good. Double check nothing has loosened up, realize I did not install the chain protector, fix that, and then the final test of taking the bike home for the day.

    Here I am headed home with the wife following behind. Took a route that allowed for lots of easy pull off points, and mostly speeds 45 mph and lower.

    The ride home was really nice and completely uneventful. Bike handled very well, nice and smooth. Chain and sprocket got along very well. I'll still be replacing them as they are old and worn, it was time for new anyways, but I wanted to make sure everything lined up first, so that I would not mess up the new.

    Here are some final setup pictures for those who want to see close ups for clearance and mounting.

    Side view from the right side showing the brake arm, lower subframe rail, and exhaust mount. Notice, the exhaust mount bracket was missed on the paint. Easy fix for later though.

    And here is from behind. I'll be replacing all the hardware, powder coating all the steel parts, and anodizing all aluminum pieces once the modifications are done for the bike. No bashing on me for rusty bolts!...

    Here is a view of the master link for the chain and the well.. dirty old chain.

    You may have noticed above the chain adjuster. Here is close up that that.

    Here is one from behind for the chain.

    and once with a flash to see the undertail currently (mostly stock).


    Currently the rear wheel is black. I'll be changing that. Probably strip it off and polish it at the least to match the front tire. All new tires with this mod, so here is pic from the front showing the exhaust and rim from the front.

    New chain and sprockets have been mounted. After a few order snafus caused the wrong rear sprocket to be shipped twice, I got the right on on the third try. 4 weeks from ordering. So now the swingarm modification is done. I'll come back and throw in a picture with the new chain and sprocket real soon.

    I can start to focus on getting the final modifications for the new plastic and paint going now. Most of the other modifications I have in mind are not nearly as intensive and can be done pretty quickly with the right materials and items.

    ***Edit 4-7-08***

    Here is a final pic with the new chain and sprocket.

    Last edited by Kreylyn; 05-31-2016, 08:22 PM. Reason: added more info...
    93 750 Kat

    Modified Swingarm, 5.5 GSXR Rear with 180/55 and 520 Chain, 750 to 600 Tail conversion, more to come. Long Term Project build thread

    "I've done this a thousand times before. What could possibly go wron.... Ooops!"

  • #2
    Very nice Tim...

    Can't wait for the rest of the story as she comes together..


    • #3
      Very cool. One day I hope to take modding to such an extreme myself, we've got dumb answers!


      • #4
        What a great write up.

        Awesome job!!!

        Now for us mechanically dumb riders (or lazy ones, you chose) when are you going to be selling those.......


        • #5
          Originally posted by katana_ron View Post
          What a great write up.

          Awesome job!!!

          Now for us mechanically dumb riders (or lazy ones, you chose) when are you going to be selling those.......
          LOL... If people want them, the welder and machinist are all set on making more.

          93 750 Kat

          Modified Swingarm, 5.5 GSXR Rear with 180/55 and 520 Chain, 750 to 600 Tail conversion, more to come. Long Term Project build thread

          "I've done this a thousand times before. What could possibly go wron.... Ooops!"


          • #6
            Lookin good


            • #7
              Congrats Krey, went the extra mile instead of just using the GSXR swingarm too.
              I am King Sam

              --I have a wedgie!
              --It's a thong, just relax and accept the string.


              • #8
                That tire looks huge hanging off the kat!


                • #9
                  Originally posted by Sambo1987 View Post
                  Congrats Krey, went the extra mile instead of just using the GSXR swingarm too.
                  not really Using a GSXR swingarm IMO IS going the extra mile, that ain't easy Good job my friend looks very good.


                  • #10
                    sigpicLife is 5% what happens to you, and 95% how you react to it
                    k9 GSX-R 600
                    GO VOLS!


                    • #11
                      Finished up mounting the swingarm and wheel today.

                      Reversed the bolts on the chain adjusters and used acorn nuts as the caps. Looks good I think.

                      Here is it as we test fit everything. You can see we bent out the rear passenger pegs to make sure we had clearance... Probably a bit too much. Put off the swap of the tail this time around to finish up the exhaust, swingarm, and rims swap. Mocked up the old change to fit (cut out 4 links) to make sure it all works. Will be ordering new sprockets and chain in the next day or so to replace them all.

                      Here is pic with it fully reassembled...

                      And a test ride from the shop to home...

                      And all I can say is... I LOVE IT!...

                      The ride is alot smoother on the turns. No more droping in, but a nice roll. Yes, it did increase the apex of the turns for the bike, but it is still way with in my riding style bounds on that.

                      The Vance and Hines 4-1 full system is off a 600 putting it pretty close to stock airflow for the 750, and is working really well. Sounds nice too.

                      93 750 Kat

                      Modified Swingarm, 5.5 GSXR Rear with 180/55 and 520 Chain, 750 to 600 Tail conversion, more to come. Long Term Project build thread

                      "I've done this a thousand times before. What could possibly go wron.... Ooops!"


                      • #12
                        very impressive. that is waaayy beyond anything i would ever even attempt.


                        • #13
                          looks good!
                          sigpicLife is 5% what happens to you, and 95% how you react to it
                          k9 GSX-R 600
                          GO VOLS!


                          • #14
                            maybe i missed it but what size tire is that? and what did you start with?


                            • #15