On Apr 21, 8:29*pm, Rob Kleinschmidt <Rkleinsch1216...@aol.com> wrote:
> On Apr 18, 10:59*pm, sean_q <no.s...@no.spam> wrote:
>
> > I've always liked single-banger motors. Would it be possible
> > to modify a BMW boxer motor such that the 2 cylinders'
> > power strokes were simultaneous instead of alternating?
>
> > In effect it would be equivalent to a thumper
> > but better balanced for less vibes.
>
> > SQ
>
> Xposting to reeky since it's pretty slow
>
> Ought to be a piece of cake on a BMW oilhead,
> as there's a separate cam for each head. That may
> leave some interesting problems with the fuel injection,
> but hey, how hard a hack could that be ?
>
> http://tinyurl.com/3m3x3gr
>
> Reeky eagerly awaits the results of your experiments.

He's wanting to make it either a twingle or a big bang motor. Twingle
would work well, but big bang? Not so well I suspect.

On Apr 22, 8:50*am, Keith <stevenkei...@hotmail.com> wrote:
> On Apr 21, 8:29*pm, Rob Kleinschmidt <Rkleinsch1216...@aol.com> wrote:
>
>
>
> > On Apr 18, 10:59*pm, sean_q <no.s...@no.spam> wrote:
>
> > > I've always liked single-banger motors. Would it be possible
> > > to modify a BMW boxer motor such that the 2 cylinders'
> > > power strokes were simultaneous instead of alternating?
>
> > > In effect it would be equivalent to a thumper
> > > but better balanced for less vibes.
>
> > > SQ
>
> > Xposting to reeky since it's pretty slow
>
> > Ought to be a piece of cake on a BMW oilhead,
> > as there's a separate cam for each head. That may
> > leave some interesting problems with the fuel injection,
> > but hey, how hard a hack could that be ?
>
> >http://tinyurl.com/3m3x3gr
>
> > Reeky eagerly awaits the results of your experiments.
>
> He's wanting to make it either a twingle or *a big bang motor. Twingle
> would work well, but big bang? Not so well I suspect.

A horizontally opposed twingle would be challenging.

AFIK, Spagthorpe was the only manufacturer who ever
worked on this concept. Their Pariah enjoyed some
success, but blown head gaskets were always a problem
in the large common combustion chamber.
was

On Apr 22, 9:50*am, Keith <stevenkei...@hotmail.com> wrote:
>
>
> He's wanting to make it either a twingle or *a big bang motor. Twingle
> would work well, but big bang? Not so well I suspect.

Wouldn't it double the power-pulse load on the crankshaft as both the
cylinders fired at once?

Or is there something I'm not seeing here?

On Apr 22, 2:39*pm, sean_q <no.s...@no.spam> wrote:
> There are two applicants for its motor:
> the '78 Dnepr MT-10/36 and the R75/5 bare frame I also just bought.
>
> If I choose the Dnepr I'll need an adapter (~$100) so that
> the Soviet transmission will match up to the BMW motor (with some
> futzing. Someone local on the Dneprheads blog did the same
> conversion and is advising me on this).

>
> Uh, looks like the Dnepr wins. The bare frame will have to gather dust
> until some other bent Beemer shows up. Which it should, eventually,
> and I can afford to wait.

So is this the BMW or Dnepr clutch ? Or some
unnatural combination of the two ?

On 4/22/2011 8:18 AM, Rob Kleinschmidt wrote:

> Go for it Sean. We'll hold your coat for you while you
> do battle with this project.

Thanks for you generous offer. Just gimme a sec while I search
Craig's for a suitable test candidate.

Meanwhile I gotta figure out what to do with this R75/5 write-off
I just bought. There are two applicants for its motor:
the '78 Dnepr MT-10/36 and the R75/5 bare frame I also just bought.

If I choose the Dnepr I'll need an adapter (~$100) so that
the Soviet transmission will match up to the BMW motor (with some
futzing. Someone local on the Dneprheads blog did the same
conversion and is advising me on this).

However if I build up the BMW frame to a complete bike then it'll
cost me close to $2k to have the Dnepr sidecar fitted to it
(at Side Effects in Kamloops).

[...doing the math...]

Uh, looks like the Dnepr wins. The bare frame will have to gather dust
until some other bent Beemer shows up. Which it should, eventually,
and I can afford to wait.

ps. the bare frame came with a collection of loose parts. Mostly junk,
but there are some usable pieces including cylinder heads. There is
a R60/6 write-off available which could be upgraded to 750cc.

SQ

On Apr 22, 11:30*am, Twibil <nowayjo...@gmail.com> wrote:
> On Apr 22, 9:50*am, Keith <stevenkei...@hotmail.com> wrote:
>
>
>
> > He's wanting to make it either a twingle or *a big bang motor. Twingle
> > would work well, but big bang? Not so well I suspect.
>
> Wouldn't it double the power-pulse load on the crankshaft as both the
> cylinders fired at once?
>
> Or is there something I'm not seeing here?

No I think (but can't prove you are correct) that is the real problem.

On Apr 22, 11:20*am, Rob Kleinschmidt <Rkleinsch1216...@aol.com>
wrote:
> On Apr 22, 8:50*am, Keith <stevenkei...@hotmail.com> wrote:
>
>
>
>
>
> > On Apr 21, 8:29*pm, Rob Kleinschmidt <Rkleinsch1216...@aol.com> wrote:
>
> > > On Apr 18, 10:59*pm, sean_q <no.s...@no.spam> wrote:
>
> > > > I've always liked single-banger motors. Would it be possible
> > > > to modify a BMW boxer motor such that the 2 cylinders'
> > > > power strokes were simultaneous instead of alternating?
>
> > > > In effect it would be equivalent to a thumper
> > > > but better balanced for less vibes.
>
> > > > SQ
>
> > > Xposting to reeky since it's pretty slow
>
> > > Ought to be a piece of cake on a BMW oilhead,
> > > as there's a separate cam for each head. That may
> > > leave some interesting problems with the fuel injection,
> > > but hey, how hard a hack could that be ?
>
> > >http://tinyurl.com/3m3x3gr
>
> > > Reeky eagerly awaits the results of your experiments.
>
> > He's wanting to make it either a twingle or *a big bang motor. Twingle
> > would work well, but big bang? Not so well I suspect.
>
> A horizontally opposed twingle would be challenging.
>
> AFIK, Spagthorpe was the only manufacturer who ever
> worked on this concept. Their Pariah enjoyed some
> success, but blown head gaskets were always a problem
> in the large common combustion chamber.
> was-

ah yes...sadly the web page is down so I can't research it, pitty that.