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Thread: Bringing back a rough J1

  1. #1
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    Bringing back a rough J1

    G'day all,

    Getting back into some Z50 builds after getting side tracked with work and other bike builds.

    I picked up a really tired J1 from a mate, had a few bits missing but it seemed salvageable, unfortunately no pics of when I first got it.

    I'm starting with the frame, and its got the usual, bent fork plate, missing nuts, broken bolts in threads, fair bit of corrosion, and a stuck rear brake pedal.






    First step was the stuck brake pedal, after lots of heat, WD40, hammering, and swearing, I got nowhere except for a few more dings in the frame. Resorted to the grinder and that fixed in a few minutes.



    I'm drawing up a new brake pedal shaft, its fairly straightforward, trying to decide on the type of steel, I'm thinking something like a 1030 should be decent enough without any problems welding. Anyone replaced one of these before?

    Jake

  2. #2
    Moderator GIMP_PRO's Avatar
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    I was lucky enough that a member had actually made me a replacement shaft. I got no idea on what he made it out of, but I made a replacement part for the frame and welded in the shaft, came up nicely.

    Some photos for inspiration (copy and pasted from the post)







    Find some donor metal


    Test fitted the plate to check my high tech drawings




    Fixed the welds up at the back




    Welded it up




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  3. #3
    Moderator dex's Avatar
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    Moved to j1 resto section
    its engine oil madge ,,,
    Your soaking in it ,,!!

  4. #4
    Life Member Peter's Avatar
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    Quote Originally Posted by Mech_Z50J1 View Post
    I'm drawing up a new brake pedal shaft, its fairly straightforward, trying to decide on the type of steel, I'm thinking something like a 1030 should be decent enough without any problems welding. Anyone replaced one of these before?

    Jake
    I'm pretty sure it's just mild steel, they bent fairly easy. :-)
    I've tried different materials, plasticine was a bit too soft so I tried a piece of wood dowel, it was easy to shape and drill but burst into flames when I tried welding it on. Steel seemed the best stuff to use so I'd recommend it.
    Keep up the good work and also the pictures coming.

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  6. #5
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    Thanks for the info, knocked up a quick drawing for a new shaft, made the section that goes in the frame a larger diameter as its going to need a bit of cleaning on the frame (I was a bit rough getting at the original shaft):

    DSC_3950.jpg

    Got the new shaft, seems like it should do the job:

    DSC_3952.jpg

    The new shaft fits the brake pedal better than off my old J1!

    DSC_3953.jpg

    Now I need to get onto the frame!

    Jake

  7. #6
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    Started the frame today, the bent steering stop tab was pretty easy to get rid off with some grinding:
    DSC_3989.jpg
    DSC_3999.jpg

    Just need to make up a new tab from some pipe/tube, unfortunately pipe/tube ID of 46mm (OD of head tube) isn't a common size, I'll just have to go with the closest:
    DSC_4005.jpg

    The stuck rear lower fend mounting bolt was a bit of a pain, thought I would try a small easy out I had, that only made things worse...snapped off inside the bolt

    Drilling out and punching through the busted easy out:
    DSC_3990.jpg
    DSC_3991.jpg

    Drilled clean:
    DSC_4000.jpg

    Tapped and good to go:
    DSC_4003.jpg

    Jake

  8. #7
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    New steering tab:

    The head tube is 46mm diameter, I had a few different ideas to make up a new replacement steering tab, but it was eventually made up by turning a 46mm tube up, 4.5mm wall:

    DSC_4030.jpg

    Then the tab was cut out and filed up:

    DSC_4031.jpg

    Ready for welding onto the head tube.

    Jake

  9. #8
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    Rear frame fender nut:

    Start with one of these:

    DSC_4047.jpg

    And after mucking around way too much, you can make one of these:

    DSC_4048.jpg

    If only I had some 1/2" hex bar...unfortunately a simple M6 nut has a smaller body than what these are...would you be able to tell the difference? Probably not, but I'm just doing it for fun...

    DSC_4045.jpg

    Ready for welding:

    DSC_4046.jpg

    Jake

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  11. #9
    Moderator Diggs's Avatar
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    Great skills mate, something I really envy is the ability to work metal like this.
    Rigby "No dude, you're doing it wrong! Righty-tidey, lefty-losey! Not lefty-tidey mess it up because you're a loser!"

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  12. #10
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    you have great skills , and way too much spare time . I would just buy the nut needed !

  13. #11
    Moderator dex's Avatar
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    Top way of doing the steering stop
    its engine oil madge ,,,
    Your soaking in it ,,!!

  14. #12
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    Just a quick update, not much progress.

    Holding rear nut in place and welding it up:

    DSC_4074.jpg

    Then smoothing out the welds a bit:

    DSC_4082.jpg
    DSC_4184.jpg

    Tacking the steering stop in place to check the travel range and make sure it clears the tank:

    DSC_4080.jpg
    DSC_4170.jpg

    Then weld it up fully:

    DSC_4177.jpg

    Welding up the brake pedal shaft and smoothing out the welds:

    DSC_4078.jpg
    DSC_4180.jpg

    That's the frame pretty much ready for blasting and painting.

  15. #13
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    Fork outers

    Checking out the forks, looks like one of the threads needs a clean, its an M34x1 thread, I'll have to see what I can clean that up with.

    DSC_4189.jpg
    DSC_4187.jpg

    Right hand indicator mounts is missing a wire hold tab, but I've got some replacement wire for that, I only need about 20mm out of the 30m!

    DSC_4010.jpg

    Otherwise, forks seems pretty decent.

    Cheers

    Jake

  16. #14
    Senior Member mick's Avatar
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    Loving the engineering. Done most of this stuff myself. Grab yourself a thread file from a nut and bolt shop or engineering supplies shop. About $35 from memory. Make sure it has the 1mm pitch on it. Good for internal and external threads. Will take a bit to restore threads but a life saver. Good for steering stem thread also. M22 x 1.
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    Plated bits

    Got some plated bits done, in a silver/gold finish and also some chrome:

    DSC_4233.jpg

    Although the plastic didn't fair too well on the handle bar knobs:

    DSC_4235.jpg

    I'm going to try and paint these up gloss black, any decent products out there that adhere well to plastic?

    Jake

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  19. #16
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  20. #17
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    Engine

    Thought I would take a look at the engine, I was expecting it to be pretty rough from what I could see on the outside:

    DSC_4236.jpg
    DSC_4237.jpg

    Everything seems to be corroded and stuck good, dirt in lots of places, hardly any oil..shes had a hard life.

    DSC_4241.jpg

    In the end I found some pretty bad news, shift drum stopper separated and mangled up a few things, looks like it may have been over tightened and the spigot on the case itself has failed:

    DSC_4261.jpg
    DSC_4264.jpg

    I've got some spare J1 cases, this one will be stripped for parts, maybe I'll find a good RH case some day...

    I doubt I will get a full set of internals, I can already tell there's some bad signs in the crank and trans too...

    Jake

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    Back to the frame:

    The frames pretty much done, although the races looked trashed, so I punched out the old ones to replace with new:

    DSC_4293.jpg

    I made up a headset bearing press out of 50mm aluminium bar and a 220mm M12 axle:

    DSC_4305.jpg
    DSC_4306.jpg
    DSC_4303.jpg

    Greased up the frame, and froze the bearings:

    DSC_4348.jpg

    New bearing seated:

    DSC_4350.jpg

    Cheers
    Jake

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  23. #19
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    Back to the forks

    Back to the forks, got my hands on a thread file and used the 1.0 mm pitch thread. The filing was pretty easy, the 34mm fork diameter is large compared to an M6x1.0 for example, and the file is guided pretty easy on the thread.
    DSC_4494.jpg

    Here you can see the stuffed thread, most of it looks like a combination of grease/dirt/corrosion, but some of the thread body has been worn away.
    DSC_4483.jpg

    It only took about 15 min for each leg, threads look pretty sweet.
    DSC_4497.jpg

    Most importantly the fork caps go on nice and easy:
    DSC_4495.jpg

    Cheers
    Jake

  24. #20
    Moderator MattyP's Avatar
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    This is really great. Well done. I could do with a set of those bearing presses.

    Keep up the great work
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    Making up the wire holders for the indicators...trying to anyways:

    DSC_4502.jpg

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    Moderator Diggs's Avatar
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    Geez, attention to detail much??? Good effort!
    Rigby "No dude, you're doing it wrong! Righty-tidey, lefty-losey! Not lefty-tidey mess it up because you're a loser!"

    ZRX1200S, RGV250 VJ22, Skyteam T-Rex, Z50J1 '78, XV250 Virago

  27. #23
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    Quote Originally Posted by Mech_Z50J1 View Post
    Making up the wire holders for the indicators...trying to anyways:

    DSC_4502.jpg
    Great work so far. Need to flatten the end that is welded to the tab otherwise it won't look original...

    I've spent $100 to make a $10 part so makes perfect sense to me .

  28. #24
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    More fork work

    flattened the indicator wire holders and cut it to size, doesn't look too bad:

    DSC_4504.jpg

    DSC_4510.jpg

    DSC_4506.jpg

    Should pass once painted up.

    Jake

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  30. #25
    Moderator Diggs's Avatar
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    I didnt even know these were missing on my J1 till I saw this thread! Now I am not sure what to do with the wires!!!!
    Rigby "No dude, you're doing it wrong! Righty-tidey, lefty-losey! Not lefty-tidey mess it up because you're a loser!"

    ZRX1200S, RGV250 VJ22, Skyteam T-Rex, Z50J1 '78, XV250 Virago

  31. #26
    MOTY Winner 2012/2013 babu's Avatar
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    Quote Originally Posted by Mech_Z50J1 View Post
    flattened the indicator wire holders and cut it to size, doesn't look too bad:

    DSC_4504.jpg

    DSC_4510.jpg

    DSC_4506.jpg

    Should pass once painted up.

    Jake
    I was only stuffing around but great work!!!

  32. #27
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    Finished off forks ready for painting.

    DSC_0006.jpg

    DSC_0005.jpg

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