Transverse vs. Longitudinal - Some Folks Are Confused

 I keep seeing motorcycle journalists, whom one would think would know better, get the issue of engine orientation exactly wrong.  Some even go way out of their way to get things wrong.  Engine orientation is described for motorcycles exactly the same way it is for cars, so let's start with some cars before moving to motorcycles.  To make things easier, I'll start with cars that have some sort of similarity in order to make the comparison and contrast easier.

I have an affection for Saabs.  My dad bought a new one in 1959.  I later owned two of them.  My daughter even had one.  So let's start with some Saabs.

Here's one like my dad's.  Is this engine transverse or longitudinal?

Know the answer?  Good.  Let's keep going with its 4 stroke successor.  Transverse or longitudinal?

Got it?  Same answer as above or not?  Okay, the 99 and 900 came after the 96.  Is this 900 engine transverse or longitudinal?

Is it getting easier or harder?  Let's move on to the 9000, the ultimate pre-GM Saab.  Transverse or longitudinal?

Hmm.  What do you think?

Okay, enough of that foreign stuff, let's look at some good old American iron like these two Fords.  Transverse or longitudinal?

Which are they?  Are they the same or different?  Why?

If Saabs are too obscure, and Fords too ordinary, what about F1 from the sixties?  Looking at these two engines, transverse or longitudinal?

They don't look the same, I mean apart from one being a V8 and the other a V12.  I'll give you a clue; they're not the same.  One is transverse and the other is longitudinal?  Which is which?  Why?

Okay, how about something a little less exotic, but still pretty exotic, Lamborghinis from the 70's.  Which is transverse, and which is longitudinal?

Which is which?  Why?

Okay, enough for cars.  Let's talk motorcycles.  In the seventies and eighties we were introduced to the term UJM (Universal Japanese Motorcycle) which made the inline 4 ubiquitous, but they weren't the first production 4's.  Way back before WWII, four cylinder motorcycles were made in the USA too.  Which is transverse, and which is longitudinal?

Which is transverse and which is longitudinal?  Why?

The Germans were late to the party, but in the 80's BMW had to join the fray with their K bikes.  Transverse or longitudinal?

Transverse or longitudinal?

In this century, Triumph has built a big part of their brand on triples.  Here are two.  Which is transverse, and which is longitudinal?

Which is transverse, and which is longitudinal?  Why?

Okay, let's move on to something that is both simpler and less obvious.  Two 250cc 4-stroke singles from two European manufacturers.  Which is transverse and which is longitudinal?

Here's your Rosetta Stone:  The BSA is transverse, and the BMW is longitudinal.  Do you know why?

Okay, if you've gotten this far, that's great!  Even better if you're figuring it out.  Are you ready for your final exam?  Two Italian, aircooled, 90 degree V-twins.  Which one is transverse and which is longitudinal?  Why?

Which is which?  Did you pass?

Here's the answer: Engine orientation is determined by the orientation of the crank compared to the rest of the vehicle.  Vehicles in which the crankshaft of the engine is oriented in the same direction as the path of travel are by definition longitudinal.  Vehicles in which the orientation is orthogonal to the direction of travel are transverse.  It's not determined by the pointy-outy bits that are easy for uninitiated to see.  It's determined by the crank.