Cylinder Position

[Air4Life]

Does anyone know why the left was designed forward of the right, I assume earth rotation and political leanings have nothing to do with it?  More room for the shifting foot is one plus.

[Barry]

More room for the shifting foot is one plus.  

Can't think of a better reason.

[Bob_Roller]

I believe it's because the connecting rods have different bosses on the crankshaft, one is in front of the other .


http://www.realoem.com/bmw/showparts.do?model=0364&mospid=51897&btnr=11_1716&hg=11&fg=21

[Barry]

The crankshaft having separate big end journals is of course why the cylinders are staggered but given that they are staggered I thought the question was why choose the left cylinder to be forward of the right. It could have been the other way around.

It would have been possible to have the cylinders in lie using a forked conrod design like Harley V twins but that's more complicated.

[Air4Life]

Bob's factual reply had me rethink my initial post.  I thought, like you Barry, that it was a reply as to how the contraption is what it is.

However, my original intent was, how did the designers decide to place the left in front of the right?  Was it a convention of sorts, functionality, or simply chance?  

In the same vein, why did God make designer's responsible for the size bell bottom jeans?

[montmil]

BMW Airheads, air-cooled flat-4 VWs, Continental, Lycoming aircraft engines, etc...  Engineers have yet to figure out how two connecting rods can share the same crankshaft journal without using a forked rod.

Original design decisions for the Airhead may have to do with the gearbox and driveshaft orientation. Let's go ask Snowbum. He's probably got a 2500-word treatise on the subject.

Several observant, non-gearhead peeps that have spent a little time around my Airheads ask the same question.    

[Air4Life]

That's interesting you should indicate that about "non-gearhead peeps" making that comment.  For me the bike has never been very attractive to look at; however, I do like that little engine, on many levels.   I would never pretend that there wasn't a certain aesthetic seduction coming from having them cylinders hanging out there.

Off topic I know, but I thought it important to disclose my true feelings.

[tvrla]

The bell bottoms question isn't in the same league at all!

Another possibility - since most of us get on and off from the left side, perhaps it had something to do with having more room over there.

This probably was something carried over from before the first BMW motorcycle, when they were building engines for those other bikes. Remember, Max Fritz adapted the engine they were already selling to other bike manufacturers.

And the first ones had hand shift, so the idea of having more room for the shifter doesn't fit. Or maybe it does - maybe it gave more room for the hand shifter.

Is it the same with the VW boxers? Left side forward of the right?

[Justin B.]

For me the bike has never been very attractive to look at

I remember buying my first BMW in 1976 and thinking it a very odd looking bird and a bit homely.  Over the years they've grown on me and I don't feel comfortable on anything else...

[JPSpen]

I bet the decision went like this...

Eenie Meanie Miney, MO....

John

[markrennick]

I remember buying my first BMW in 1976 and thinking it a very odd looking bird and a bit homely

I remember seeing police bikes back in the 70s, before I was old enough for a moped.. gawking at the big cylinders. And the magic numbers on the side panel (six HUNDRED ccs!!)

Must have made a big impression on me, & I still love the look. Although the crankcase was odd looking. I used to think it was called a boxer because the engine was hidden in a box!

[Barry]

Until I owned an airhead I hadn't noticed the extent to which the cylinders were staggered. I don't recall any casual observers noticing until I point it out, then they are surprised by how quirky the layout is.  I suspect many who have ridden an airhead for the first time don't notice straight away.

[montmil]

Old Hippies and New Agers rebuilding their vintage VW air-cooled engines sure know about it.

Boxers Forever!

[tvrla]

I owned the R90 for two years before noticing the left foot peg was farther forward than the right side. How weird is that???

These bikes give an impression of being symetrical, but it's ONLY an apparency!

[marcmax]

I knew the cylinder were slightly staggered but I never noticed the footpegs were until I read this. I just went into the garage to check and can't believe I never noticed after all the mile I have put on it.