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A post following the build of my bike - Kutay

Discussion in 'The Garage' started by Kutay, Dec 27, 2023.

  1. Kutay

    Kutay XS400 Member

    I think I will post how the build of my bike is going here. so i cant rack down any info in the future and hopefully some things are helpful for some people.
    so far:
    I bought a working xs400 in shambles. The frame was brown, the rear was chopped off, no seat, sketchy wiring, no blinkers. The bike had to be rebuilt. Being a student and having a small room i thought this was a great idea.
    Here is the bike when i first bough it with ziptied janky seat on it

    I had to learn to weld, because why not.
    First i stripped everything down and put all the screws into a single bag like a genius. That made me loose track of every single on of them and treat every threaded hole as just a hole with no corresponding screw in the future.
    Here is the bike striped down with sketchy welds behind my room.
    Some of ym bad welds for the hoop as well. I was getting hopeless with the welding. I used fluxcore welding and there wasnt much info online about parameters and the hoop I ordered didnt have the right dimensions. I didnt want to wait anymore. So i just went for it. Being flux core you cannot do multiple passes and i burnt through much of the thin material.
    Here is the bad weld for the hoop, my thinking was, i wont sit on this part of the bike so it can be bad. IMG-20210307-WA0007.jpeg
    then I focused on studying and not failing university courses. Meant 4 years of nothing on the bike. Just wheels, fork, tank, engine was installed. This year I had some time and money so i started on it again. Previously I had made a electronics tray and ziptied it on, someone stole it and my foot pegs. I had to get it done again, it was expensive and lots off effort to find a private laser cutter to get the tray cut for me so i could bend and weld it. It is done now, and the tray fits in beautifully. Also started my motorbike license, small detail. Joining the uni workshop was a blessing. They have all the tools and i dont need to move my bed and wardrobe to work on the bike each time.

    First i wanted to start by making a seat pan. Seeing people do it online it seemed simple enough. It was, but you need to think about whats going to happen in the following 5 steps. I didnt. I spent 6 hours one night and layered a seat a cowl in one go. The mistakes i made were
    - Making the cowl and the seat in one piece
    - Not ensuring a flat surface on the seat
    This meant i couldn't have a plate to wrap the leather around and glue foam onto. Because the cowl was connected tot eh seat i couldn't just wrap around leather over the whole thing. I cut it but then i also realized the gap i left for electronics was too big. Rather than spending couple days dreadfully bodging it together, i am going to redo the seat, this time with a plan :D.

    There is a long list of things to do step by step right now. What i learnt so far is, have a plan. Dont just do it and figure it out on the way. And what i haven't learnt yet is where to find a shifter since my broke.

    Next i will be making a pin and arms and alignment pins for the seat pan i will make and also a foam mold for the seat cowl.
    tstidham likes this.
  2. Kutay

    Kutay XS400 Member

    Yesterday was another 6 hour workshop session. I cut the rear hoop, I realized it had to be longer and I didnt trust the welds. Turns out my welds were solid and I forgot even that I had placed solid pieces inside the tube. The hoop is now 13 cm further back, the welds are better and it was really difficult to weld due to material thickness difference, it is done. I want to add a brace still to make it a little bit more stiff and give it rigidity. I can lift the bike just by holding the hoop, so I'd like to assume its strong enough. It wont carry my weight, that is already relieving. The welder ran out of CO2, that needs to wait. In the mean time I'll be making the pins so the seat can align with the frame and not pivot at the top and bottom connection points. Also arms for the seat to 'hold' the frame below the tank and a pin for it to click into the lock at the back. Today I should get bunch of materials I ordered online, fiberglass, epoxy, handlebars etc. I got some foam yesterday, which was really expensive for no reason. Tonight ill be focusing on making a cowl mold, then maybe cutting the fiberglass sheets to length. Tomorrow I'd like to lay the fiberglass over the cowl already. The day after that cut the cowl to shape, the day after that make the seat. I am in winter holiday right now, before it ends, I want to finish the seat pan and the cowl.
  3. Kutay

    Kutay XS400 Member

    The fiberglass cowl is done. I spent 4 days in total. 2 days for foam shaping 1 day for fiberglass 1 day for taking it out and welding a structure to the frame. I will upload some pictures. This time it turned out tge way i wanted it to. I will fill some irregularities with body filler. Right now bike is ready fir another fiberglass session, the seat pan. In the meantime I decided to do a RS125 fork swap. Lets see how that turns out. Havent ordered the forks yet but the just the yoke. I thought with the RS125 yoke i have more fork options. RS125 is definetly a good options tho. I am just searching atm.
    tstidham likes this.
  4. Kutay

    Kutay XS400 Member

    I got rubber parts to connect the carbs to the air filters. They haven't arrived yet but the rubber advertised had the correct inner diameter. I had problems putting on the stock rubber. Here is teh link for EU in case anyone else has the same problem with the air filter carburetor connector rubber https://vrachtwagens.autodoc.nl/lema/14348376
    tstidham likes this.
  5. Kutay

    Kutay XS400 Member

    The seat is dry and I shaped it. I did a bad job on the tank side. But i will ignore it and let tge foam cover it. I have been shaping foam from the original bike. Its been really vauge because it is flexible. Here are some pictures from the process.
  6. drewpy

    drewpy Excess twin Top Contributor

    can't see any pictures Kutay
  7. Kutay

    Kutay XS400 Member

    Ooh the legend drewpy. Aaaah you are right hahaha.
    The foam mold for the cowl 20231230_163059.jpg 20231230_172911.jpg

    The bike under fiberglass, the seat pan is drying

    Fixing the cracked light housing quickly with leftover fiberglass 20240103_230045.jpg
    New extended back without the supports welded. This was somewhat difficult. The bavk was cut too short, so I welded a solid cylinder with very high Amps. Then welded a tube over it and connected them to the hoop. Screenshot_20231228_094358_Video Player.jpg
    gpounce32768, CaptChrome and drewpy like this.
  8. Kutay

    Kutay XS400 Member

    The foam is cut to shape. 20240109_122021.jpg

    The leather work needs to be done now. I have exams so the bike will be left to utself for about 1 month.

    I did the thing, got RS125 forks :D. They arrived yesterday and are really impressive, especially after the 30mm forks we have on the XS400. I bought and axle hopefully it fits, otgereise i will just machine my own. Handlebars are stuck in tge upper triple, those need to be drilled out. Afterwards i will machine my own handlebars too.
    The picture will follow.

    My questions are...
    How can I measure, what can I measure to figure out what bearing I need to fit a RS125 2001 triple to the XS400?
    The forks are leaking so I want to rebuild them. What should I look for. Any known dimensions? Advice from someone experienced would be great!
    gpounce32768 likes this.
  9. drewpy

    drewpy Excess twin Top Contributor

    usually the xs steerer tube is taken off the lower triple and reattached to the RS tree
  10. gpounce32768

    gpounce32768 XS400 Enthusiast

    I got a bit inspired by the idea of somewhat better forks, so opted for an ebay vz800 triple-tree and forks. Apparently they will fit well- will have a try at adapting that to the bike in the spring. Apparently the axle is the same diameter, so will need some spacers machined and some kind of brake adaptation.
  11. Kutay

    Kutay XS400 Member

    Tried the forks yesterday. I didnt change anything they seemed to fit. How can I make aure the bearings contact all along their contact surface?
    The triple feels smooth and has no move when i assemble it. I assume it fits. Ill machine spacers for the front wheel. And I dont know how to work around the tachometer. Anyone any advice?
    Ordered new bearings to fit the larger RS axle.

    I also realised a little late. Is the frame too close to the back wheel. Will it hit when the suspension is compressed?

    My questions:
    How can I deal with the speedometer?
    How can I make sure the triple crown fits and it doesnt only contact partially?
    Rear wheel rub and solutions?


  12. Kutay

    Kutay XS400 Member

    Update us om how it goes gpounce32768
  13. Kutay

    Kutay XS400 Member

    Also ordered a brake disc and a calliper. I will be looking for a 12mm master cylinder I think. First I want to try with 11mm one we have on the XS. The ratio between 12mm master and 4 piston rs125 calliper is 25.00 i think. That is in the sweet range of 27-23.
    I am expecting the delivery of:
    Wheel bearings
    Brake light
    Fork seals
    Fork dust covers

    I will update the sizes once they fit. I still need headlight brackes, which has been a struggle. I dont want the sheet metal AliExpress one thats everywhere. But i dont know where to fit 50mm brackets. Still need mirrors, ignition switch, master cylinder, glue for foam. Then i have everything to assemble the bike :D
  14. Kutay

    Kutay XS400 Member

    Finally got some pictures from my camera. One with the old forks. I will change the colour of the bike to red,white,black, but for now it looks like the following.

    Attached Files:

    tstidham likes this.
  15. Kutay

    Kutay XS400 Member

    The fiberglass cowl i made is a good shape i think, but it doesnt cover the black hoop, or the frame. I assume it will not be so obvious once it is painted, now it is bare metal so it shines. Any opinions on that, i was thinking maybe i should make yet another cowl to cover the sides. Or jsut wait untill the seat is finished. Added a cheeky Honda cub 50 pic as well. Quick side project.

    Attached Files:

    gpounce32768 likes this.
  16. drewpy

    drewpy Excess twin Top Contributor

    I'd leave it, I like the way you can see the frame. more interesting to look at
  17. tstidham

    tstidham XS400 Addict Top Contributor

    Lol, from the thumbnail of the cub, my brain short circuited for a second thinking you put a cub knee fairing on the XS! I've only had a few sips of coffee so far, so I'm not fully awake either!

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