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First Cafe Racer Mod! 1983 XJ750 Maxim

Discussion in 'XJ Modifications' started by May_J_Aaron, Jun 24, 2018.

  1. Minimutly

    Minimutly Well-Known Member

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    On this subject I have bought from a major UK supplier, two new ignition switches and a fuse holder. The fuse holder was a direct replacement using glass fuses. It looked fine, untill I looked at the crimped leads - they were tiny compared to the Yamaha ones. This made me look into the ignition switches - similarly, the red and browns were no bigger than the blues. Absolute chinese rubbish. I binned the fuse holder, and after checking the internals of the switches soldered the old leads onto the new switches. Fingers crossed and lesson learnt.
    Edit to add a question to @chacal - are the light switch wires in the main/dip switch the same for bikes with and without headlight relay? Ie can they be swapped between bikes?
     
  2. May_J_Aaron

    May_J_Aaron Josh May

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    I purchased a marine grade fuse block, the upgrade was easy and even easier once I unwrapped the wiring and untangled them, suddenly had more wire to work with! :eek::D
    @chacal also sells them
     
  3. May_J_Aaron

    May_J_Aaron Josh May

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    SUSPENSION!!!!
    Ok so I was planning on doing a hoop and seat setup just about exactly like this:
    B683927B-54E7-4CB2-8A0F-C702EA23AE25.jpeg

    But upon setting up my phone to record and bouncing up and down on my frame in a way that I’m glad no one was watching... my tire goes up past the frames.
    I planned on creating a flat pan that smooths out the underside of the subframe underneath the frame rails and down to the swing arm mounts but suspension compression would bottom out, possibly even solo!....

    now my stock suspension is likely worn out, I had it to near max stiffness and it was still a concern.

    What have people done with suspension to prevent bottoming out?!

    I would like to occasionally have a passenger but if I have to make it a solo bike, I will.

    Im 6’1” 195 lbs
     
  4. 50gary

    50gary Active Member

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    You need higher rate rear springs.
    When you say you had the rear suspension near maximum stiffness I take that to mean you had it at max preload?
    Learn to measure "sag" both without and with rider.
    Cheers, 50gary
     
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  5. XJ550H

    XJ550H Well-Known Member Premium Member

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    rear wheel travel is 3.8 inches 96 mm. I guess you flatened the seatpad/lowered the seat.

    do you have original rear shocks with the thumb wheel adjuster?
     
  6. May_J_Aaron

    May_J_Aaron Josh May

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    Yea they look original!
    357CE26B-70D1-48E8-948B-373E9ECC2BDE.jpeg

    I’m curious that since the plastic dome under the subframe goes up about 2.5 above the lowest part of the rear subframe, should I increase the length of the new shocks by that much?
    Being stock as well as 36 years old, I’m sure they were never quality in the first place since that’s where companies tend to go a little cheap on

    I plan on having this welded on
    D7F2397D-D2D5-47AB-858B-99E0515CE2EA.png

    And since I plan on having the seat thickness just a bit higher than the gas tank end, the passenger is going to need all that space for cushion!
    357CE26B-70D1-48E8-948B-373E9ECC2BDE.jpeg
    under the frame rails I will be creating a mud guard, can likely give it a slight dome curve but very little
     

    Attached Files:

    Last edited: May 27, 2020
  7. XJ550H

    XJ550H Well-Known Member Premium Member

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    no that will affect the driveshaft angle and may wear out the ujoint quickly

    thats a stock shock

    maybe find a way to raise seat and cover the gap.
     
  8. May_J_Aaron

    May_J_Aaron Josh May

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    With bike on center stand, end to end of mounts is 14”, when I sat at it with max preload, it was 13”, when I hop up and down on it it moves roughly 3-4”... and that would be a very uncomfortable ride!
     
  9. May_J_Aaron

    May_J_Aaron Josh May

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    I do feel like I will have to curve the future mud guard underneath to have the space but I’m curious what others have used that have done similar projects
     
  10. May_J_Aaron

    May_J_Aaron Josh May

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    How about a 1 inch increase in shock length?
     
  11. Polock

    Polock Well-Known Member

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    lot to be said for monoshocks
     
  12. XJ550H

    XJ550H Well-Known Member Premium Member

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    an inch seems to be acceptable
     
  13. May_J_Aaron

    May_J_Aaron Josh May

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    No load (center stand) 14” - with highest preload setting
    Max compression 11” - lowest preload setting

    bottoms out at top of frame rail at 11.5”.
    So instead of putting a mud guard on bottom of rails, it’ll have to be above the rails just under future seat pan. Sounds like an extra inch on new rear shocks may solve clearance issues!
    I’m surprised suspension only travels 3 inches! :eek:
    A65090EF-6D8B-4ABD-84D3-34F117BD55A1.jpeg 4BF6A4C3-C6E4-41F6-88C9-DB944D9AFF86.jpeg
    (Those are the ladies finger nails:p)

    So I can likely accept a shock between 380-390 mm with a max compression down to 290 Mm

    I’ve seen Progressive, Hagon, and YSS recommended within a good price range in the forums, any other recommendations?
     
    Last edited: May 28, 2020
  14. PavelK313

    PavelK313 Active Member

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    It really depends on your budget, but from personal research I came to conclusion that Progressive is best bang for the buck when it comes to quality.
     
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  15. 50gary

    50gary Active Member

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    What you are calling the dome or bulge, (the plastic, black curved thing) is called the inner fender. There is no way you should have to change or modify the inner fender for tire clearance.
    The top of the inner fender will be at the same height as the cafe seat so no contact will happen even at full compression.
    The cafe type "hoop" might contact the tire on full compression if the "legs" of the hoop are too short allowing tire to contact the hoop. You're good with adding photos, show a mock-up of the
    hoop in place (tape it in place where it would be welded) picture in pure profile and you'll be able to see if the tire will hit the hoop. If the tire contacts the hoop you may need a hoop with longer legs
    (legs being the straight part of the hoop) All things being normal the suspension should be able to move though it's full range of motion without hitting anything.

    "when I hop up and down on it it moves roughly 3-4”... and that would be a very uncomfortable ride!" Not to be rude but no, not necessarily. What would make a rough ride would be a suspension
    that's too stiff, non-compliant. All the shock of the bumps would be delivered to you and your lady friend's backsides. Also the "thickness" of the seat will not make a difference, the placement of the
    underside of the seat. (seat pan) could cause tire to seat contact. I'm doing something quite similar, I'm keeping the factory inner fender and extending it straight rearward (horizontally) even with stock shocks there's
    no interference or contact. I'm using 13" Center to center YFR (cheap chinese) shocks but with the 8mm (heavier) diameter coil spring wire. The softer version of these shocks have 7mm wire.
    Sorry for the long post just trying to clarify some points.
    Cheers, 50gary
     
    Last edited: May 29, 2020
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  16. May_J_Aaron

    May_J_Aaron Josh May

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    I was thinking the same thing
     
  17. May_J_Aaron

    May_J_Aaron Josh May

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    [QUOTE="when I hop up and down on it it moves roughly 3-4”... and that would be a very uncomfortable ride!"[/QUOTE] @50gary
    No worries, I meant that I had it set to max preload settings to test the limits of it all, so the settings would have been the uncomfortable part vs having it where I normally would.
    When I used the ratcheting tie downs to hold it for measurements and for testing, the tire went just above the top of the frame rail "legs" which is actually about where I planned on having the hoop...
    You make some great points and I may have to consider whether to make it solo and fabricate a rear tire fender or go longer for clearance of the hoop. :confused:
    Ultimately I wanted the entire rear inner fender space from top of rails to be seat cushion.
    Not wanting the setup to sit so high and thick as the stock seats were.
     
    Last edited: May 29, 2020
  18. May_J_Aaron

    May_J_Aaron Josh May

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    @50gary So when looking through your project, you basically did what I intend to do but you have to upswept hoop yet created the rear fender which would technically give you even less clearance.
    This works for you using a shorter shock with heavy duty springs? have you bottomed out ever?
     
    Last edited: May 30, 2020
  19. Polock

    Polock Well-Known Member

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    you should get a stick with holes the distance of your bottomed shocks and use that for shocks in your eye balling adventures
    quit bouncing the bike, your going to hurt yourself :)
     
  20. May_J_Aaron

    May_J_Aaron Josh May

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    I really liked the Progressive 430’s but they have a cruiser look to them (great for Bobber style) so I’m going with the 412’s 13.5” and here’s why!

    After conservatively chopping off unneeded metal and measuring clearance with tape, total suspension travel unloaded vs loaded with 2-up “simulating bumps” was 2.75”.

    me sitting solo, all 195lbs.
    5EE1C395-5A40-4BFE-9DD4-1869DE15FD93.jpeg DD543941-E906-440F-8A5D-DBD7A492D47B.jpeg

    simply 2-up without moving, the tire reached the bottom tape, bottoming out.
    EEE3F6BA-CF64-471E-88C3-A885D1D457FF.jpeg


    the rear tire would reach the upper tape on the frame rail but not quite hitting it but easily broke through the bottom tape.

    so my conclusion is that the stock 12.5” worn out 36 year old shocks should be fine getting replaced by Progressive’s 412’s 13.5” shocks that will give me extra space for compression yet resist bottoming out much better, if not, it’s Amazon and I’ll just return them!
     

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