Dirt Bike History 101

Discussion in 'Old's Cool' started by kittycactus, Jan 21, 2008.

  1. motu

    motu Loose Pre Unit

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    Another thing that sunk the big British singles and twins and pushed the 2 stroke forward was changing tracks.The old bikes were made for natural terrain tracks...just a few pegs in a paddock and you had an MX track.The old bikes were made for sliding out of a wide flat turn with thick loam as a surface,they jumped long and low on jumps that were just natural hills.

    Then came man made tracks....still in the paddock,but tighter turns with man made berms.The jumps were man made too,with much steeper ramps so the bikes now jumped high.The bikes became shorter to turn sharper,lighter with better suspension to jump higher.As bikes became better,the tracks became tougher to make it more competitive.
    #81
  2. motu

    motu Loose Pre Unit

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    #82
  3. nachtflug

    nachtflug infidel

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    I've said it before and I'll say it again. The roots of "dirt bikes" in the US are deepest in California.

    From what you could glean from month old magazine information, you wouldl realize that in California, they weren't just doing it on Sundays. :huh

    totally incomprehensible for northeast mindset back when we'd be snowed in for months and then had to deal with MUD for months and then the heat and humidity in the summer along with green overgrown trails that the ungloved hand would become a pin cushion of prickers from.

    and here and there someone would move west, to california...the name looms as large as any in the history of .."dirt bikes"..
    #83
  4. nachtflug

    nachtflug infidel

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    bingo. I never quite know how to vocalize the Husky tanks. thats as good a job as any. there was/is a pretty sweet one for less than $3K not long back on the VMX BB. of course in...California...

    I remember them now as 4 speeds. I'll be those bad boys will keep the front end light at the appropriate times. :huh
    #84
  5. nachtflug

    nachtflug infidel

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    I think the biggest question is...are todays young guys faster riders or are they just riding faster..

    talk about the $64K question.
    #85
  6. nachtflug

    nachtflug infidel

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    sweet. I'd relink the pic but our poor thread starter is on dial up. not sure if it would even matter?
    #86
  7. El Hombre

    El Hombre Banned

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    And reading in those same magazines 'We don't care HOW they do it in California'. Those were in the letters to the editors from the REST OF THE WORLD.

    I was in Michigan, graduating HS in '70, moved to the Bay Area in '76, lots better out here, for all the reasons you mention.
    #87
  8. Gordy

    Gordy Team Listo

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    Revisting the forward shock movement for a bit:

    When the first Elsinores came out they had standard mounting for the shocks. We moved the top mounting forward to get a few more inches and this seemed to work OK with the stock forks. But you know how if a little is good a lot is better? We then moved the bottom mount (on the swingarm) up as well, and this gave us about 10.5 inches in the rear, IIRC and a wicked rake angle in the front. :huh Lots of trial and error finding a spring that would work with the increased leverage. At first, we would just install a stronger spring and did nothing with the damping. We had no clue. This is when Fox Shox (you know, the guys with the clothing line) came in.

    In those days, if you could find a welder, you had a "works bike"! :lol2

    This is also when the the problems with chain tensioning began.
    #88
  9. Gordy

    Gordy Team Listo

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    Same in Phoenix. I moved there for a bit and we could race on Friday night, Saturday night and Sunday mornings. There were guys doing that regimen in two classes!
    #89
  10. Valleyrider

    Valleyrider I Survived The '60s

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    Never got a chance to weigh it. This was back in the early 70's. The bikes arrived by airfreight from Japan and left the same way. They were very light, not sure just how light. Joel broke several frames. The frames were so light they would grow in wheelbase several inches over the span of a couple of motos.
    #90
  11. dan-c

    dan-c Undescended Testicle

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    Water cooling was a hugh breakthrough. IIRC the first attempt at water cooling (~75 :scratch) was a trick head (fox, denco :dunno ) that used passive cooling i.e; the water jacket was in the head, as the water heated it would circulate to a small radiator, be cooled and returned to the head. No pump or anything
    #91
  12. Valleyrider

    Valleyrider I Survived The '60s

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    Wow! I raced with Don at Trojan!! It's been 40 years since I've seen him. It was about that time that the motocross and speedway guys split off from the flattrack/TT group. Larry Shaw's (Speedway "Lightning Larry Shaw") father used to try to get me drunk before the races at Elsinore. I was 19 or 20 at the time and he would make me wine coolers before the races started. Thought it was pretty cool drinking with him!! Then I finally realized what was happening. Larry could never beat me sober or tipsy.
    Troy McKee was the fast guy in the 100cc class on a Hodaka. Can't remember who did his engines, but he had a reed valve setup on it and it Hauled A$$. Tom Berry had a fast YL1 Yamaha that had the rotary valve on the right side, but also had a second carb. Again, can't remember who built it, but It was fast when it ran...
    #92
  13. nachtflug

    nachtflug infidel

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    someone remarked it looked like a works bike but it looks like a stocker to me. KX400 by the looks of it. Jug is too big for a 250. Pipe is stock in its routing but definitely new hand made pipe. The first KX's were pretty decent, my cousin had a 73-250 that ripped pretty good, but again, the Elsinores were a little better and their sheer numbers in riders on the starting line gave them that much of an extra edge. But the KX's were good. Fast and light.

    I was very surprised at the number of this vintage KX (1973-75 ish) at the Mid Ohio Vintage Days MX this past summer. The guys I chatted with claimed parts were easy to find and cheap. There were a lot of them there and going pretty good to boot.

    The KX 400 was the runt of the litter in that most people running in the open class were still running European bikes with the odd Suzuki or Yamaha thrown in.

    But this could be a works bike, its hard to tell. My money is on stock KX 400.
    #93
  14. nachtflug

    nachtflug infidel

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    and just for the Kawasaki record..

    the KX's came out in 1973 with a 125-250 and 450. 1973 was the only year of the 450, as the following year it was a 400.

    So a 450 KX is rare in its own right. It also did not have the shiny metal green tank with the white stripe, instead a dull green plastic tank with black lettering only.

    like this one a Mid Ohio.

    [​IMG]

    and the pipe was unique to that bike in that it came up and then leveled off at the back.

    [​IMG]
    #94
  15. nachtflug

    nachtflug infidel

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    can't resist posting another Mid Ohio pic.

    nothing like a bunch of loud 2 strokes winding up!!

    [​IMG]
    #95
  16. kittycactus

    kittycactus Banned

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    The subframe is on top of the rear fender? How long did that last?
    #96
  17. nachtflug

    nachtflug infidel

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    low pipes pretty much put it at pre 1977ish on all jap.

    Non leading axle forks were also passe' by the late 70's.

    the white stripe Kawasaki's like the one you were inquiring about are mostly 1973 ish since the stripe was black on the 1974's. I think. :D the stripe and lettering definitely changed and that is an earlier one.

    Here is a 1976 KX 400.

    I believe the black fenders are correct. but I'm not sure. :D

    [​IMG]

    not quite as "white" in the striping as the earlier ones.

    [​IMG]
    #97
  18. nachtflug

    nachtflug infidel

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    depends how long it took you to loop it. :D
    #98
  19. nachtflug

    nachtflug infidel

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    most anyway. :D

    the CR125's stayed with the low pipe till....
    #99
  20. Strong Bad

    Strong Bad n00balicious

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    It wasn't really a sub-frame as it was welded to the main frame.