[help] Ideas needed for a motor

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
criteria.

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
SQ

 

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.

 

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).

 

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.

SQ

 

You could get a complete BMW R75 and just move the sidecar over...

// Hans

 

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
easier

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

SQ

 

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

 

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.

SQ

 

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...

 

Quality