Dirt Bike History 101

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

  1. mtothef

    mtothef Been here awhile

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    and all that swede-built entailed:

    35mm forks with ten inches of travel, where we used to rotate stanchions 180 degrees every race or two to keep the bending back and forth consistent.

    automatic transmission bikes that worked incredibly well while filling your crankcases oil with tiny pieces of brass.

    the most beautiful dentable gas tanks in the world. ever.

    power delivery that would make a rider cry if he was trying to race against japanese 250s by the early 80s. unless we're talking about enduros, in which case, with king richard burleson as saint and guide (13 national championships in a row has to be doing something right), that tractable engine just laid waste to everyone else.

    handling. hmmm. straight line awesomeness. cornering, well, sort of the anti-maico. look for the berm, forget about the inside line. try to avoid bending the forks.

    sigh, i miss my old 250xc...
    #61
  2. modre

    modre Banned

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    Originally Posted by kittycactus
    When the jap bikes were first introduced in the states, how were they received; were people excited about them or were they looked upon with distain like the Chinese bikes now entering our market, some of both?


    I was there.

    if it's still running, the AMA museum in Pickering Ohio has an evolution of the dirt bike exibition that would have been invaluable for your education.

    the dirt bikes were single BSAs and single and twin 4 stroke Triumphs and a couple odd Swedish things....I had a 500 T100C and a bother had a 441 Victor. the race guys were flirting with 2 strokes... Bultacos and such because of the power to weight advantage...what was happening was 125cc 2 strokes were killing 500 4 strokes as riding styles changed from manhandling meat to surfing loose...and folks noticed that...that shifted everything to 2 strokes...it wasn't motocross yet...it was still hare scrambles. when the jappers came in, they already had a hip audience so the bikes were quickly received...blew the old 4 strokes away...at this time it became motocross as suspention travel began to increase...then came the exotic maicos, ossas and the others later.

    there was always the buy union American foot draggers that snickered, but the hipper guys were winning...and it's hard to argue with success...the 73-ish CB750 "superbike" changed a lot of minds, but it took a period of transistion.

    if you can find mc magizines of the period, I'm sure it's well documented.

    I remember Dirt Bike and Dirt Rider...there were others.

    it wasn't just the bikes...it was suspention travel, 2 strokes, and a change of riding styles all in a casserole...just as helmet laws came in and exclusionary tactics in county parks and such...motorcycles were always on the fringe, but it became a threat during this period.
    #62
  3. dan-c

    dan-c Back

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    Don't forget reliable :deal Maico's usually had to be dialed in after every moto. The Jap bikes, you just changed the plugs.
    #63
  4. mudgepondexpress

    mudgepondexpress Long timer

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    Hey Steady...

    Love the old school pics of both you and your father but I have to ask...what is the story with the Honda sticker on an obviously Yamaha bike (DT of some sort, 250/DT1).

    Kenny
    #64
  5. ADK

    ADK ____

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    2 strokes kicked 4 strokes to the curb in the early 60s when a CZ engineer invented the expansion chamber.
    #65
  6. kittycactus

    kittycactus Banned

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    I understood about the other classes, but not this one?
    #66
  7. Gordy

    Gordy Team Listo

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    I don't know where the hell it came from either. :dunno It must have carried over from an enduro class (which we had zero interest in).
    We always had a few guys show up at the MXs with 175 Pentons and they were soon joined by 175 IT Yamahas.

    What a bunch of tools, running around the course with enduro light kits and quiet mufflers. :lol2
    #67
  8. dan-c

    dan-c Back

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    Well in the later days, post '77 the ones they raced are like this one (unless you had a Hercules or Jackpiner or MZ or...

    The IT Yammies were actually pretty competetive too :augie


    :fyyff :lol3
    #68
  9. JAB

    JAB Unsprung Weight

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    Don't want to start a who, when, where issue, but I think chambers go back further than the 60's. Look up some the crazy engineering from DKW road racing and I believe you'll see chambers, 2 strokes with superchargers, all sorts of crazy stuff.
    #69
  10. ADK

    ADK ____

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    I'm no absolute authority on this.Maybe CZ was the first to use expansion chambers in MX?
    #70
  11. nachtflug

    nachtflug infidel

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    more than one might think. the magazines (and dealers) played a bigger role then. as far as when, for me its harder to pinpoint, but someone who saw the 60;s blend into the 70's would probably take a good stab at it.

    a few biggies that did just fine without todays marketing juggernauts and no internet.

    Preston Petty fenders. Moto X Fox. Even Hooker Headers. And in a lot of cases, the last thing you needed was an aftermarket pipe, (TM 400:huh ) etc.

    But again a good question. When things were "the hot setup" everyone got one. The Whirlpull Throttle 0r Gunnar Gasser. Hi Point boots. But these are 70's. Like a lot of things back then you would mail 50 cents for a catalogue from whoevers stuff you had an eye on.

    Tough one to answwer definitively...

    great thread!
    #71
  12. nachtflug

    nachtflug infidel

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    :D

    :hide
    #72
  13. camgregus

    camgregus riding gently now

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    I had (have the shell -motor) a 250 yammie just like that IT.

    (doesn't matter to the 175 discussion) Loved that bike. handled decently and really had great power. Lots a top end in fifth. Hang on til ya chicken out.

    Horrible seat though.
    #73
  14. flying_hun

    flying_hun Moral Hazard

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    I was thinking it was MZ. Didn't Walter Kaaden develop them for MZ's roadracers? Then Ernst Degner defected to the west and took the engineering secrets to Suzuki. Who said the Japanese didn't copy anyone else?

    Regarding old Huskies, my WR250 didn't really like turning either, nor were its brakes much to write home about, but what a sweet motor! An easy bike to ride all day.

    As for all the different displacements, when two strokes first were built over 250cc, the metallurgy and general engineering were a little marginal for dealing with the increased heat. As the factories learned from their experiences we saw the growth from 360s to larger engines. There was lots of experimenting. Many folks found the 250's easier to ride, as an earlier poster stated.

    I would argue that water cooling was a big break through. It wasn't long after radiators appeared on 125's that an aircooled bike become too slow. Water cooling allowed engines to be built to generate more power because liquid did a better job of letting the engine effectively shed the heat that comes with more power. Tighter tolerances can be used by thermal expansion of dissimilar materials happens in a more controlled fashion with liquid cooling than air cooling. I still prefer the look of an aircooled motor, but power is power.
    #74
  15. gonridn

    gonridn Been here awhile

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    that bike was considered an 82 1/2 model. nicknamed the " Silver Bullet" for the beautiful silver paint job. the last of the polished knee panels style tanks. the first ones came with a giant 44mm mikuni carb. the white 83 models went to a 40mm. it was only available as a cr version with a 4 speed transmission.
    #75
  16. Valleyrider

    Valleyrider I Survived The '60s

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    That's some real HI-Tech mods done by the factory mechanics!! Most everything on the RH and RN was basically one off/handmade. The fork tubes were so thin that these were the early version of rock protectors.
    #76
  17. Gordy

    Gordy Team Listo

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    :thumb DAMHIK

    [​IMG]

    1977 250 CR


    I don't know who/what I am chasing!:lol2
    #77
  18. El Hombre

    El Hombre Banned

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    Have you ever put it on a scale? Rumor back then was 168 pounds. For a 250, not a 125.

    When no one else could keep up with it, the FIM made a minimum weight rule. 208 pounds?
    #78
  19. Strong Bad

    Strong Bad n00balicious

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    <o:p> </o:p>
    Interesting thread, to say the least. I grew up in <st1:place w:st="on">Southern California</st1:place>, graduating from High School in 1970. I remember the GYT kitted Yamahas at Trojan speedway, and at <st1:place w:st="on">Elsinore</st1:place> and Parris.
    <o:p> </o:p>
    Fresh out of high school I got a job porting cylinders for the once famous EC Birt, owner of Precision Cycles. Precision Cycles was a small shop that sold Macio, Rickman, Hodaka and a few obscure brands like Zundap, Puch, & Carabela. EC had a reputation for speed tuning, you told him what kind of rider you were and he developed a package for you that typically included a port job, custom expansion chamber, head work, and carburetor. Long before the factories used reed valves EC had picked up on them from the kart racers. We were making tons of money converting piston port bikes to reed valves. One of the more popular reed valve conversions were for the CZs being sold up the street by Joe Kubacheck. One thing you have to remember was that most of the 2 strokes being sold were really mild in their tuning. With little effort at all in the early 70’s you could double the horsepower of a stock bike. Bikes that werent too mild were too wild (Suz 400 cyclone) there you made money by building a pipe with more center section and mellowing them out. The guys who bought our stuff thought we were magic. EC had a huge ego and somehow he figured out that magazines have no clue as to anything other than selling magazines and that they were always desperate for something to write about. EC came up with the idea of inviting a magazine into his shop so he could share his “Hot Tips” and secrets. OMG, the sales went through the roof! We were cranking out a half dozen port jobs and a dozen pipes a day.
    <o:p> </o:p>
    The down side was that EC was a pain in the ass and a real jerk to work for. His main mechanic was pissed off enough and had a good enough relationship with the customers that he decided to open his own speed shop. He started in a garage he didn’t even attempt to try to pick up a dealership. I used to port for EC during the day and then at night I would go over to my friends business in the garage and port at night. Oh yeah the mechanic’s name Donny Emler. In a very short time, one of his best customers bank rolled Donny into business as Uncle Donnie’s Flying Machine Factory.
    <o:p> </o:p>
    All of this happened just about the same time the Honda Elsinores took off. Honda had done their home work and the “You meet the nicest people on Honda” took motorcycles from Hells Angles to the guy next door. <st1:place w:st="on">Southern California</st1:place> was exploding with motocross. You could race 4 to 5 times a week if you wanted to. The 125 Hondas were easily improved with a port job and a pipe. Uncle Donny took full advantage of EC’s magazine techniques and soon he was off and running selling all we could make via magazine exposure. The biggest thing to happen for Donny and what became FMF was that one of the riders he had sponsored as a young gun got picked up by American Honda. That young gun, Marty Smith, demanded that his bike use a FMF pipe, and as such, FMF became the first after market pipe on a “works” bike. I guess it was kind of good for sales eh?



    Well, my glass of Scotch is empty and the rest is a blur anyway, so I'll leave it at that for now.
    <o:p></o:p>
    #79
  20. vintagemxr

    vintagemxr old fahrt, nobody special

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    Interesting thread. So many memories from way back then. In some ways riding was different then in the sense that the land was still pretty much wide open: Just go ride. When people first talked about closing off parts of the desert for something called "ecology" whatever we just laughed because the desert was public land and public land belonged to everyone so you couldn't close it. :cry

    We (Bultaco racers) used to say that Maicos used the finest mahogony bearings money could buy. Of course Bultacos were the very model of reliability. :nod

    Happily, riding now feels just as good as riding 40+ years ago; crashing hurts a little more though.

    Below, that's me in my traditional "middle of the pack" race mode circa 1970 at a motorcross race in La Mesa, CA:

    [​IMG]

    Something here that I wrote a few years ago about "trail riding" as a kid.

    Doug
    #80