[help] Ideas needed for a motor

Discussion in 'Classic Motorbikes' started by sean_q, Apr 29, 2011.

  1. sean_q

    sean_q Guest

    I have a '78 Dnepr MT-10/36 with a sidecar. I want to replace
    the (non-running) Russian motor and drive train. Criteria:

    * capable of 65 mph max. Probably need at least 50 hp

    * 750 cc max (for insurance purposes)

    * reliable

    * robust clutch as rig with sidecar is heavy (heavier than Ural)

    * good torque (ditto)

    * easily obtainable & affordable

    * easily maintainable -- parts & service

    * chain drive

    * must fit in Dnepr frame (with custom fabricated adapting brackets)

    The first candidate that comes to mind is the Honda CB750. Assuming
    it can be fitted to the Dnepr's frame it seems to fit all the other

    Of course I would be sacrificing the period character of the boxer
    motor (and would scandalize any purists) but my main objective is
    a reliable machine that can haul a passenger and a load of groceries.

    Any comments and/or other ideas appreciated
    sean_q, Apr 29, 2011
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  2. I reckon BMW is the way to go, too; mostly from the form POV but partly
    because they're likely to have better low-end grunt for pulling a heavier
    contraption around, but that's only a guess on my part.

    Puzzled by the chain drive requirement: are Dneprs chain drive? If so,
    might be awkward.
    PipL alter ego, Apr 29, 2011
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  3. sean_q

    Krusty Guest

    Too easy, too common. Sean appears to want something a bit more
    interesting, & good on him for that. It's a shame about the cc limit or
    I'd vote for a big Guzzi lump (assuming the budget won't stretch to a
    Rocket III).
    Krusty, Apr 29, 2011
  4. sean_q

    sean_q Guest

    I should have explained this part a bit better: the Dnepr is shaft drive
    so I'd have to either modify the swing arm or install another one
    from a chain-driven bike to facilitate tension adjustment. Once this
    was done I'd use the donor bike's rear wheel. (Or use some kind of
    tensioning idler sprocket; perhaps spring-loaded like the Buell Ulysses:
    http://thekneeslider.com/images/fusionbuell.jpg <-- idler is red.
    However I'd prefer chain drive rather than belt drive.)

    My 1st idea was to use the complete drive train from motor to rear hub
    from an R75/5 or /6. However its frame is too different for this
    to be easy; I'd have to fabricate a custom swing arm.

    Chain drive is easy to maintain/repair/replace. Also, I can easily
    exchange the stock rear sprocket for a larger one to trade off
    high-end speed for better low-end torque.

    sean_q, Apr 29, 2011
  5. You could get a complete BMW R75 and just move the sidecar over...

    // Hans
    Hans Joergensen, Apr 30, 2011
  6. sean_q

    sean_q Guest

    That option involves:

    1. having to fabricate custom adapters for the BMW frame
    to accommodate the sidecar

    2. modifying the BMW front end for less trail to make steering

    I got a quote for both of the above from a specialty shop
    (Side Effects in Kamloops, BC) for approx Cdn $2000.

    sean_q, Apr 30, 2011
  7. All BMW's are able to be used with sidecars.. Though perhaps only on
    the right side.. :)

    Also you can get bolt on adapters afaik.

    // Hans
    Hans Joergensen, May 1, 2011
  8. sean_q

    sean_q Guest

    That was true on the older models (up to and including the /2).
    However, starting with the Rxx/5 in the early 1970's there was
    no sidecar support. Or so I've been led to believe.

    Anyway my 1973 R75/5 bare frame has no attachment points.
    Well that would be good if I could find them.

    However, the /5 and /6's have a removable rear sub-frame which is
    nowhere near as strong looking as the main frame; not something
    I'd care to bolt a sidecar to.

    And of course there's the steering issue. The leading link front end
    on the /2 has two settings, one for normal use and one for a sidecar.
    There's nothing like that on my /5.

    sean_q, May 1, 2011
  9. I've never come across a reasonably-sized motorcycle that was unsuitable
    for hanging a chair on.

    While soe forks are better than others for the purpose, I can't think of
    any which are really bad news.

    Setting-up the combo - lean-out of bike, tow-in of chair, lead of
    sidecar wheel over rear wheel will all adjust until steering is a pleasure.

    I reember Dick Mares of Upminster Bridge being nicked for 'not being in
    proper ontrol of his vehicle' - testing an outfit he'd just put
    together, coming down Upminster Hill standing on the dual seat with his
    arms outstretched...
    Macabre of Auchterloonie, May 5, 2011
  10. Quality
    The Older Gentleman, May 5, 2011
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