1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

kaw kz750 twin dohc electric start in a commando frame

Discussion in 'Other Norton Motorcycles' started by 84ok, Sep 2, 2018.

  1. 84ok

    84ok

    Joined:
    Aug 10, 2014
    awhile ago, started a thread - 'diff engines commando frame', turns out there have been a few including, yam xs650 twin, early honda cb750-4 (mighta been fb frame), triumph trident..

    so, have some bits now to check out the possible kz750 twin engine in a commando frame,

    along the way heard/found out about balance factor & isolastics intended/designed to work with the commando engine setup

    assuming the kz750 360deg crank counterbalanced engine can be fitted even, some concerns that come to mind is there room to remove the top valve cover for valve adjust, also room for in frame head/barrel removal

    or before i go any further with possible fitting, haven't a clue if the stock kaw engine is workable with the isolastics?

    have read that isolastic adjustments for the stock setup are not only critical for engine smoothness, but can also end up cracking frames,

    the kaw (76-84) is also 5 speed, some were rear wheel belt drive
     
    Last edited: Sep 2, 2018
  2. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    Those kwack lumps were a bit gutless from what I remember, I have seen a commando frame with a hilman imp engine fitted,these were usually fitted in featherbed frames
     
  3. 84ok

    84ok

    Joined:
    Aug 10, 2014
    https://www.accessnorton.com/NortonCommando/different-engine-commando-frame.19741/

    they were advertised ~ 55 horse & picked one up with a good story complete for 100 bux ..pretty heavy lump

    this woulda been my first choice ~ 80 horse, 5 valver, early ones are 360deg cranks, maybe down the road..
    https://en.wikipedia.org/wiki/Yamaha_TDM850
    https://www.ebay.ca/itm/YAMAHA-TDM8...m=401433003462&_trksid=p2045573.c100033.m2042

    i've seen early cb750, xs650, prob others & pretty sure at one point there was a possibility (or looked into at least) of a factory effort, triumph trident engine fitted to a commando frame for sale, any info on how the isolastics were worked out in that engine combo?

    eitherway, have the bits now to see how the kaw motor may fit, when it gets warmer..

    2 main mounting points are visible this side, there is one more @ the bottom, back end
    [​IMG]
     
    Last edited: Jan 25, 2019
  4. Bodger

    Bodger VIP MEMBER

    Joined:
    May 9, 2017
    Dont take offense, but I'm not following the logic of your project unless you just happen to have a Commando frame and want to see if it can be done.The Kwaker has a balance shaft and therefore is relatively vibration free. The Commando frame was designed to "subdue" the unbalanced Norton engine's vibes. It would seem to me to make more sense to put the Kwak engine in a featherbed frame. Simpler installation without worrying about isolastics. Simpler frame with (more or less) rigidly mounted swing arm. It takes a really well set up Commando to match the handling of a featherbed. Ok now I'll go slink off.....
     
    texasSlick and Hortons Norton like this.
  5. 84ok

    84ok

    Joined:
    Aug 10, 2014
    have a frame, cradle/swingarm, z plates, front engine mount


    [​IMG]
     
    Last edited: Jan 25, 2019
  6. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    re; "they were advertised ~ 55 horse & picked one up with a good story complete for 100 bux ..pretty heavy lump"

    yes, they were heavy, but bear in mind they are unit construction, which included gearbox, clutch. . . . . . . . . .
     
  7. Matchless

    Matchless

    Joined:
    Dec 23, 2010
    The gearbox sprocket woukd be a long way from the swing arm pivot, thus leading to a very long drive chain & all the problems that brings. It would also look a bit lost in the Commando frame.
     
  8. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    Does a Norton 961 engine fit the Commando frame? That would be a logical step forward. The rubber mounted cradle could be discarded and the winging arm support redesigned for a wider and stronger swinging arm. It doesn't leave much of the original Commando though. One might as well use a Metisse frame or any other lightweight frame designed to handle the increased torque as a starting point.

    -Knut
     
    Last edited: Jan 26, 2019
  9. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    I have often wondered about the featherbed frame verses the commando frame
    The featherbed certainly looks a better design for racing,as long as it has a proper head steady bracing the headstock
    But in racing did an atlas ever out perform a commando on the track?
    Or even a commando motor in a featherbed frame out perform a commando frame ?
    I used to have a 750 big valve motor in a wideline frame,crank rebalanced to atlas spec but I kept the motor leaning forward and that may have been it's downfall as the vibration was appalling
    And I wouldn't say it handled any better than a properly set up commando
    However there are plenty of commandos out there that aren't set up right and are a nightmare to ride and I can't imagine a bad featherbed being as bad as a bad commando if you get my drift
     
  10. 84ok

    84ok

    Joined:
    Aug 10, 2014
    yea a scenario but doubt making it work would be a yuuge issue, i'm also looking at extending the swingarm/wheelbase
    http://www.bikeexif.com/vintage-yamaha-race-bike
     
  11. 84ok

    84ok

    Joined:
    Aug 10, 2014
    so, first i heard, the commando isolastics were designed/setup for a particular engine setup, 360 deg crank with a given balance factor

    then i became aware of a prototype trident engine fitted

    more recently the p92
    http://www.b50.org/phpBB2/viewtopic.php?t=182

    figure i'd start out the easier way, mounting the counterbalanced kz750 as is, maybe start with zero or minimal clearance on the isolastics, then going from there

    maybe wouldn't even be a yuuge deal with a sporster engine? or perhaps some other counterbalanced V twin?

    engine shot
    http://www.netbikes.com.au/projects/z750_twin/almost_there.jpg
     
    Last edited: Jan 27, 2019
    MichaelB likes this.
  12. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    If you go ahead with this I can see your biggest problem will be mounting the swing arm to the engine,
    The new engine/swing arm mount will have to be a perfect fit at the motor
    Any movement at all will spell disasteress handling
    Are there 2 engine mounts at the front of this engine?
    I suspect you'd need to use a longer swing arm with this short Kawasaki engine
    Don't forget the trisolastic didn't work because of the vibration frequently of the Trident engine
    Yours already has a balance shaft
    I wish you good luck with it
    Cheers
     
  13. 84ok

    84ok

    Joined:
    Aug 10, 2014
    i figure the stock cradle iso deal but modified to bolt up to the kaw,

    there are 2 main front mounting points on the kaw frame, upper & lower, the upper right uses a triangulated bolt in bracket

    looks like 2 at the back
    Broken link removed
    [​IMG]


    also 2 on top

    bottom line on going this way is first finding out if the head & barrels can come off without an engine out
     
    Last edited by a moderator: Feb 12, 2019
  14. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    I'd assume you would have to remove the engine to pull the head off but how often would you need to do that?
    I would just go for it if I were you
     
    Last edited by a moderator: Feb 12, 2019
  15. 84ok

    84ok

    Joined:
    Aug 10, 2014
    Last edited: Feb 27, 2019
  16. 84ok

    84ok

    Joined:
    Aug 10, 2014
    can't find the link but read that a yam xs650 engine assy is ~ 150 lbs
     
  17. 84ok

    84ok

    Joined:
    Aug 10, 2014
    turns out a major issue from the get go, the front lower pan area of the kaw engine is quite wide & will not go in the commando frame lower rails (doubt the featherbed also), which would have to be widened

    prob one of the first things to check/sort out for anyone looking at fitting another engine
     
  18. kommando

    kommando

    Joined:
    May 7, 2005
    The bottom rails on a Commando frame are not load bearing if you ignore the sidestand and mount the engine direct to the frame without ISO's at front and say a head steady, that gives you the scope of cutting part of them out.
     
  19. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    FYI, the Featherbed lower frame rails are approximately 4 inches inside to inside at the front, and widen to about 7 inches at the rear.

    Slick
     
  20. 84ok

    84ok

    Joined:
    Aug 10, 2014

Share This Page