kawasaki bighorn streettracker

Discussion in '2 smokers' started by mtothef, Mar 20, 2013.

  1. mtothef

    mtothef Been here awhile

    Joined:
    Dec 23, 2006
    Oddometer:
    411
    Location:
    santa cruz, ca...
    I picked this little gem up the other day from a guy locally who had built it as a replica of the f81m that he desired way back when. The frame was de-raked and a champion style rear loop added, then powdercoated, work done by James Banke. SR500 wheels and forks, forks are in betor triples, with a newer YZ brake caliper grabbing a rotor that looks like it came from an FZR. The motor is freshly rebuilt to stock spec, with a chamber that "probably" used to be on a Suzuki based 'tracker of some sort. It is plated, and riding it feels like I'm getting away with some sort of crime:

    [​IMG]

    This showed up on the local craigslist, where the legions of tire kickers seeking R6s to turn into stunt bikes for less than $2k probably had no idea what the hell to make of it. Having relatively recently built a hideously expensive SR500 based street tracker, and currently also being in way past my wallet on an RD350 restoration, I was all too well aware of what the owner had put into this bike, and how much below that he was selling it (which is sort of how it goes, isn't it?), so I couldn't let this pass me by. It will, at least for the time being, cure me of my need to bastardize otherwise perfectly decent mid-70s two stroke dual purpose bikes to try and emulate the same thing, and may even steer me away from my financially self destructive desire to own a Bultaco Metralla.

    For now, BRAAAAAAAAAAAAP!:freaky
    #1
  2. BIG ED XT FAN

    BIG ED XT FAN Long timer

    Joined:
    Feb 18, 2006
    Oddometer:
    1,261
    Location:
    Finger Lakes Western New York
    Thats cool!! Green Bikes always look:lol3:clap:freaky:wink::deal good!!
    #2
  3. CharlieT

    CharlieT old school

    Joined:
    Jan 17, 2006
    Oddometer:
    1,741
    Location:
    Kalamazoo
    I feelbad for you that you feel like your committing a crime riding that. TO alleviate the guilt you feel, I think you should sell that bike, preferbly to an old geezer that bought an F81M in 1971 and raced it for a couple of years. :deal:evil:evil
    #3
  4. Sic Semper Tyrannis

    Sic Semper Tyrannis Plays with Banjos, Boats and Bikes...

    Joined:
    Aug 9, 2009
    Oddometer:
    852
    Location:
    RVa
    I think street trackers will be the next "Big Thing"....

    That looks like way too much fun!!!!
    #4
  5. Sniper X

    Sniper X De Oppresso Liber

    Joined:
    Jul 18, 2006
    Oddometer:
    33,474
    Location:
    Central New Mexico, 7420ft above sea level
    I doubt it. I built one back in 1995 and have still seen only a handfull even on the net. I will say they and a supermoto are the most fun thing to ride on the street. Super mot hasn't really taken off like I thought it would either. Doesn't matter, I still will have one as my next bike.
    #5
  6. ADK

    ADK master of the casual pace

    Joined:
    Dec 5, 2005
    Oddometer:
    8,266
    That's a thing of beauty, hard to believe a guy went to all that trouble then thought "meh, it's outta here."
    #6
  7. lrutt

    lrutt SILENCE.....i kill you

    Joined:
    Jul 25, 2005
    Oddometer:
    1,906
    Location:
    Deltona, FL
    That is one sweet 2 smoker. I used to tangle with those old kwakers all the time on my RT1. Those were some good times.

    Hell, I built one back in 1981 and still can count on one hand the number I've seen on the street other than my old XR.

    Sure wish I would have kept that bike.

    [​IMG]
    #7
  8. mtothef

    mtothef Been here awhile

    Joined:
    Dec 23, 2006
    Oddometer:
    411
    Location:
    santa cruz, ca...
    yeah, but you shoulda seen his triumph!
    #8
  9. dan-c

    dan-c Undescended Testicle

    Joined:
    Aug 19, 2005
    Oddometer:
    14,170
    Location:
    SATX
    Coolest bike I've seen in a long time. Congratulations. Fuc^er :D
    #9
  10. supershaft

    supershaft because I can

    Joined:
    Sep 9, 2010
    Oddometer:
    9,116
    Location:
    San Francisco Bay area
    Awesome!!!

    There were a couple of fast experts around when I was a kid riding those.

    I didn't realize they were ever injected.
    #10
  11. dan-c

    dan-c Undescended Testicle

    Joined:
    Aug 19, 2005
    Oddometer:
    14,170
    Location:
    SATX
    You mean rotary valve? IIRC all Kaw Enduros were rotary valve :scratch
    #11
  12. Foot dragger

    Foot dragger singletracker

    Joined:
    Dec 27, 2006
    Oddometer:
    13,843
    Location:
    chico,just below rag dump(nor-cal)
    Oh Yeah,I remember those Bighorns. I rode one once that had the factory kit on it,it ran pretty darn well.

    I gave a guy a ride to a TT race one time,it was his first race and he was riding a stripped Bighorn. He smoked the novice class to the point where it was ridiculous,coulda been in the hunt with the amateur/expert class.

    Next time he raced was on a fully sponsored Bultaco.

    Buying that one you got already settup like that sure saves a lotta work and money.
    #12
  13. mtothef

    mtothef Been here awhile

    Joined:
    Dec 23, 2006
    Oddometer:
    411
    Location:
    santa cruz, ca...
    i wish. i can't leave well enough alone though... took the beast for a good shakedown ride in the twisties on saturday. clutch slips, parts are already on order. the engine was rebuilt to stock, jetting is close to stock, i think previous owner actually leaned out the main a bit. i did a couple plug chops and things looked okay, but there were a couple moments where i heard some detonation rattle. according to los hermanos Klemm, who have to be THE brain trust on these engines, that is kind of par for the course with these bikes and what passes for gas these days.

    aaanyway, the expansion chamber hits pretty bad when you try to go around any corner that isn't a left hand corner. and the bike has no discernible hit. grunty, easy to ride, mellow and fun. feels almost like a four stroke. the itchy part of me wants to pull the top end off, send it to Klemm for some porting and squish mods, then cut the rotary valve, then weld up a proper chamber, then get a slightly bigger carb and jet it for angry riding, then shave a bunch of eight off the flywheel. all of which will probably make it a whole lot faster but also less reliable, and will considerably unweight my bank account.

    for now, i'll ride it as it is. it's quirky and fun, and not likely to make me try and do anything heroic. and i need a runner for the time being. at least until the RD moneypit gets finished...
    #13
  14. supershaft

    supershaft because I can

    Joined:
    Sep 9, 2010
    Oddometer:
    9,116
    Location:
    San Francisco Bay area
    The oil tank?
    #14
  15. CharlieT

    CharlieT old school

    Joined:
    Jan 17, 2006
    Oddometer:
    1,741
    Location:
    Kalamazoo
    The F81m , which of course came with no lights, had a very small internal flywheel, that is, internal to the coils. Yes the bike was a faster and when it came up on the pipe it was explosive. TO the point it was difficult to ride at times. At the same time I also had an F8 enduro. Working on the bikes one day, we pulled to ignitions off and replaced the F81m's rotor/ignition with the larger, heavier F8 ignition. Remember, this was in the days before flywheel weights.

    The heavier weight smoothed out the ferocious hit and though the bike may have been a bit slower, I was actually faster on it. Ended up ordering another complete F8 ignition to leave on the F81m. THe other thing it did was provide the needed lighting coils which enabled me to install barely legal lighting, thus enabling me to ride the F81M in some enduros.

    As for rotary valves, as I recall, the Bighorn stayed a rotary, but the 250 changed from rotary to piston port in either '72 or '73.
    #15
  16. dan-c

    dan-c Undescended Testicle

    Joined:
    Aug 19, 2005
    Oddometer:
    14,170
    Location:
    SATX
    All Kaw two-stroke enduros and street bikes were oil injected too. In fact all Jap enduros were.
    Since the 60's?
    #16
  17. mtothef

    mtothef Been here awhile

    Joined:
    Dec 23, 2006
    Oddometer:
    411
    Location:
    santa cruz, ca...
    good info on all counts, charlie... you are correct about the 250/350 differences. the 250 bison was a rotary valve motor for only a couple years before being superseded with a piston port motor, while the 350 bighorn went from being called f5 to f9 but remained a rotary valve intake for the entire span of production.

    regarding the flywheel, i had done some digging around on f81 magnetos, and the consensus was that they were generally a drastic difference. the stock flywheel, meanwhile, weighs somewhere around 5 pounds. the klemms shave about a half pound off the outside of them to make things a bit more snappy and to decrease load on the left crank bearing. i'll probably go for that latter route when/if i get around to digging into this motor. for now, the only thing that NEEDS to be done is slap some new clutch plates and discs and springs in and call it good.
    #17
  18. CharlieT

    CharlieT old school

    Joined:
    Jan 17, 2006
    Oddometer:
    1,741
    Location:
    Kalamazoo
    OK, you made me go dig around in the few photos I have from back in the old days.

    Here's the F81M and F8 together;
    [​IMG]

    Notice the additional air intake on the case cover right over the carb. If I recall, we ended up blocking that off as it wasn't as effective as the up top filter....and also significantly lowered the depth of water crossings you could handle.

    And here is some young skinny guy (:eek1:cry) on the F81M
    [​IMG]


    Should have held onto that F81M.
    #18
  19. mtothef

    mtothef Been here awhile

    Joined:
    Dec 23, 2006
    Oddometer:
    411
    Location:
    santa cruz, ca...
    awesome pics, thanks for posting them!

    i found the F5 race kit booklet online in the kawasaki singles yahoo group, and noticed the super sketchy modified air "filter" cover. wow. dramatic increase in power coupled with dramatic reduction in top end lifespan, one might surmise...

    might have to try and get a chamber rolled up to the race kit specs though.
    #19
  20. supershaft

    supershaft because I can

    Joined:
    Sep 9, 2010
    Oddometer:
    9,116
    Location:
    San Francisco Bay area
    Enduros? TM's were injected. At any rate. I think the injection had long since been removed from the ones I remember being around. That or I just never noticed the tanks. I never checked them out otherwise.
    #20