1979 xr500

Discussion in 'Thumpers' started by woahblackbetty, Mar 6, 2013.

  1. woahblackbetty

    woahblackbetty Adventurer

    Joined:
    Mar 4, 2013
    Oddometer:
    20
    Location:
    SWMO
    Picked this little under-powered toy over the weekend. ;D ;D

    1979 XR500

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    The seat needs to be rebuilt. Mice got into it and built themselves a nest in the airbox. Had a lot more power once that was cleaned out.
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    Still needs a tune up to be 100%, currently running a can of seafoam and tank of fresh gas through it. Will be catching all the standard maintenance points in the coming weeks

    Original owner's manual was in a ziploc bag in the tool bag.
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    Tucked into the lineup... One oddball rectangular light!
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    #1
  2. Canuman

    Canuman Crusty & Unobliging

    Joined:
    Jun 21, 2008
    Oddometer:
    4,684
    Location:
    The Palace of the People, VT
    That's one sweet line-up!
    #2
  3. stiggs13

    stiggs13 Been here awhile

    Joined:
    Jul 6, 2010
    Oddometer:
    216
    Location:
    Los Angeles
    Nice pick up

    What year is the CT-90?
    #3
  4. woahblackbetty

    woahblackbetty Adventurer

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    Mar 4, 2013
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    Thanks!!

    Honestly not sure, it's a friend's bike that I'm slowly piecing back together for him.
    #4
  5. Gadget Man

    Gadget Man Out in the Garage...

    Joined:
    Feb 7, 2010
    Oddometer:
    94
    Location:
    Central Minnesota
    I once owned a 1979 XR 500. I bought it brand new in 1980.
    It was never meant to be street legal. But "back in the day" I went to the license bureau and just told them it was a Honda 500 and they gave me a plate.
    I bolted it right on the rear fender and rode that bike all over northern Minnesota for several years. I called it my two wheeled tractor. It was a great bike.

    I also had a 1972 Honda CT 90. Another awesome bike. It had the high/low gear box with the automatic 4 speed.

    I would love to find either one of those bikes for sale today.

    Good luck.
    Gadget man
    #5
  6. woahblackbetty

    woahblackbetty Adventurer

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    Oddometer:
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    :clap
    I've been naughty again...
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    GS500 wheels, axle diameters match to the XR500. Just need to get calipers & master cylinders sorted. The front wheel is already drilled & tapped from the factory for dual disc. Chain pitches match also! Like it was meant to be...
    #6
  7. woahblackbetty

    woahblackbetty Adventurer

    Joined:
    Mar 4, 2013
    Oddometer:
    20
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    Positive proof of concept...
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    A minor interference that will have to be rectified. This lug mates to the original front hub and secures the drum brake.
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    #7
  8. woahblackbetty

    woahblackbetty Adventurer

    Joined:
    Mar 4, 2013
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    20
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    SWMO
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    #8
  9. Carter Pewterschmidt

    Carter Pewterschmidt Long timer

    Joined:
    Nov 23, 2010
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    Location:
    Milwaukee
    Dig the vintage sumo concept. Plan on doing that to my XL600R. Are those Suzuki GS500 wheels?
    #9
  10. woahblackbetty

    woahblackbetty Adventurer

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    :clap:clap Yessir!!
    The GS500 and XR500 share front and rear axle diameters (15mm front & 17mm rear) as well as chain pitch (520).
    Simple drop in and install spacers front & rear, up the rear sprocket to a 49T (JT Sprockets makes one) which is the closest match to the original 14/48 ratio of the XR500.
    Going from a 130/80-18 to 130/70-17 isn't too bad of a drop and the 1T higher on the back will give a slight torque increase (because an XR500 really needs more torque right??)
    Obviously still have to get calipers & master cylinders squared away. I'm planning on using a KLR600 front wheel paired with the stock XR500 rear wheel for offroading. The KLR600 is also a 15mm front axle so I'll have to make sure that whatever my solution for front brakes is adaptable to that hub configuration.
    #10
  11. woahblackbetty

    woahblackbetty Adventurer

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    After some consideration I have decided to try rotating the fork tubes 180* to remove the interference of the drum brake lug.
    This will hopefully also allow me to utilize that lug out in front as a mounting point for part of the front caliper bracket. :freaky

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    I have a line on a GS500 rear caliper and front disc locally. Those parts plus the other farkles I'm collecting along the way have me simply needing to fab brackets and wheel spacers!
    #11
  12. woahblackbetty

    woahblackbetty Adventurer

    Joined:
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    20
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    49T rear sprocket is virtually the same size as the rear disc.
    #12
  13. wrk2surf

    wrk2surf on the gas or brakes

    Joined:
    Dec 16, 2007
    Oddometer:
    7,609
    Location:
    THE exact center of California/Bass lake/Yosemite
    NICE!!

    bam balam!
    #13
  14. Pigford

    Pigford British

    Joined:
    Sep 27, 2009
    Oddometer:
    1,019
    Location:
    North Dorset, UK
    I think you may have some serious handling issues reversing leading axel forks :huh The wheel will have a tendancy to "drop-in" :deal

    Good to see you giving it the personal treatment..... but not to my liking, but hey-ho thats what makes bikes so interesting :clap

    Heres my old XL500R...... great little bikes :freaky

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    Took me to Le Mans a couple of years back..... ENJOY
    #14
  15. woahblackbetty

    woahblackbetty Adventurer

    Joined:
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    Oddometer:
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    Yeah, I've already rotated the tubes back around the right way and swapped them left to right. That puts the axle back in front and moves the drum mounting lug outboard & clear of any interference.
    Have to fab my wheel spacers so I can finish up the bracket design for the front caliper. I have the option of a radial mount or standard mount. Unsure yet which way I'll go...
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    Obviously this isn't where I'll mount it if I go standard, I'll sling it behind the fork leg.
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    This is going to be one configuration for the XR. I'm working on securing a 21" front wheel with disc brake setup so I can run that with the stock 18" rear when I want to hit the trails hard. None of my modifications involve cutting the frame. I'm welding a couple of brackets at the back for the rear caliper stabilizer but I can swap back to the stock setup without a problem.
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    That's one sweet looking bike!
    #15
  16. Chaos-in-MT

    Chaos-in-MT OK lets GO!

    Joined:
    Sep 24, 2007
    Oddometer:
    446
    Location:
    N.W. Montana
    Gadget Man.
    You might talk me out of my 1979 XR500. Im in the process of fixing her up now. The 23 in front tire on them is kinda odd.
    #16
  17. RFVC600R

    RFVC600R SAND EATER

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    Dec 16, 2011
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    SAND LAND
    I love those older Hondas
    #17
  18. GR0NK

    GR0NK Got some screws loose!

    Joined:
    Sep 24, 2006
    Oddometer:
    3,204
    Location:
    In the Valley of the Bomb
    It may not handle badly at all, some bikes were designed that way. The Yamaha Vision comes to mind. I never had a problem with the way it handled.

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    But of course that's no guarantee THIS bike will handle correctly. I guess it's a moot point since you swapped the tubes left to right to solve your interference issue.



    Sean :bmwrider
    #18
  19. geomerc

    geomerc n00b

    Joined:
    Apr 20, 2014
    Oddometer:
    1
    Location:
    Idaho
    Hey hows your bike progressing?
    #19
  20. woahblackbetty

    woahblackbetty Adventurer

    Joined:
    Mar 4, 2013
    Oddometer:
    20
    Location:
    SWMO
    Like all things in life with 4 kids, VERY SLOWLY!!
    I gave up on trying to adapt the stock front shocks to squeeze the GS wheel & disc in as well as hooch a caliper bracket. Instead I'm swapping front ends with an '84 CR500. That's on it's way from Tampa thanks to eBay.
    Front wheel for offroad has changed to one off an RMZ450, working on machining some bearing spacers to adapt the 22mm ID of the bearing down to the 15mm front axle.
    #20