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  • On 31st March 2015

How powerful is the HONDA CB550 engine? How does it compare to other engines of its day? You are not going to believe the answers.  I guarantee it.  If you already knew the facts that I’m about to relate here pertaining to this “little engine”, the unpretentious HONDA CB550, let me buy you a drink or two please and allow me to listen to what you have to say.  I want to learn.  I like to know.  I like to find out.

The HONDA CB550 was first introduced in 1974. It was your “run of the mill”, mass-produced bike that just about anybody could afford.  There was no exclusivity about it.  It was the “Volkswagen” of motorcycles.  Produced, probably, in the hundreds of thousands.

HONDA CB550 originla look

Little wonder then that when I wrote that performance-wise the CB550-based BLACKSQUARE was roughly as good as a 2014 PORSCHE Carrera 4, the statement evoked laughter, criticism and a touch of mockery to boot.

Criticism is good.  It’s stimulating.  It’s healthy.  And it makes you go back to your homework and double-check things.  Which I did.  But before getting into details and facts, let’s put the statement I made on the board.  Here it is again:

BLACKSQUARE’S weight was reduced to a total of 375 lbs.  This makes it possible that machine and rider could weigh a combined total of 550 lbs.  Considering the engine’s displacement is 550 cc, this translates to 1 cc for a pound of weight.  That is as good as a 2014 PORCHE 911 Carrera 4 weighing in at 3,353 lbs. and sporting a 3,456 cc engine!

I know, I know.  I can hear what you are saying, “Don’t be ridiculous.  And please stop embarrassing yourself.” I, too, saw Richard’s opinion in Motorcycle Daily:

I had a 500/4 back in the day and can tell you the motor is anything but potent. Wet lettuce springs to mind.

But I can’t stop now.  I want to know how far off the mark I was.  And whatever happens, happens.

The CB550 is a naturally aspirated 4-cylinder engine with a displacement of 544 cubic centimeters (cc).HONDA CB550 ENGINE CUTOUT SAVED AS WEBPAGE FORMAT


It develops 50 horse power (HP) at 8,500 RPM.  In other words, it utilizes 10.88 cc to put out 1 HP.

Let’s remember that number:  10.88.

And let’s define it as DISPLACEMENT TO POWER (DTP) ratio.  In other words, the volume of engine displacement needed to produce 1 HP.

A very common fascination with engines is how efficiently they can use displacement to produce power.  The ultimate objective being a very small engine that produces a lot of power.  That would be the engine with the smallest DTP ratio.

For the HONDA CB550 that was 10.88.

How does that compare to the rest?

Since I used a car for the analogy I made above, we could take a look at some cars first, then, just for the sake of it, we’ll look at a few motorcycles and then, finally, at the 2014 PORSCHE  911 Carrera.

Keep in mind that the year was 1974.  The 70’s.  The decade of rock’n’roll, youth rebellion, feminists movements, American muscle cars, European sports cars, etc.  The “Me generation” decade as Thomas Wolfe put it. The decade when just about everybody could have a motorcycle. The market was hot.  The competition was fierce.  And, by the way, there were no personal computers.  Well, not on everybody’s desk or in everybody’s home anyway.  And no cell phones either.  Google wouldn’t exist for another 30 years or so.

What were the engines of those days like?

Let’s take a look.

The FORD Pinto 2.3, call it the run of the mill FORD car produced between 1971 and 1980, had a 2,302 cc 4-cylinder engine that produced 89 HP.  A DTP ratio of 25.9.

The VOLKSWAGEN Golf 1.5 had a 4-cylinder 1,457 cc engine that produced 70 HP.  A DTP of 20.8.

The PONTIAC GTO (an American classic; a muscle car that everybody wants even today) used many different engines with so many add-on’s and variations that it is impossible to list them all here.  Suffice it to say that none of the engines, varying between 6,400 and 7,500 cc in displacement and producing as much as 390 HP, had a DTP any better than about 18.

The FERRARI Dino 246 GT (1968-1974) had a 2419 cc engine putting out 193 HP.  A DTP of 12.5.

And finally, let’s take a look at the PORSCHE 911 Carrera 3.2 of the time (in production from 1973 to 1989).  It featured a fuel injected 6-cylinder engine with a displacement of 3,164 cc which produced an impressive 231 HP.  This is a DTP of 13.7.

Not PORSCHE and not even FERRARI could produce an engine that could beat the displacement to power efficiency of the run-of-the-mill HONDA CB550.

Come on!  There must have been some car engine out there that was better.  After all, the CB550 is just a simple ordinary engine with nothing fancy; it wasn’t even fuel injected.  Something had to be able to beat it.

I looked and looked, and looked some more.  And you know what?  You are right.  Something did beat it.

The LAMBORGHINI Countach LP400.

Lamborghini Countach LP400

Let me say this again, please.  In reverence. LAMBORGHINI Countach LP400.

It featured a V12 engine developing 375 HP. It was in production between 1973 and 1981.  To produce this extraordinary power, it employed a 3,929 cc engine.

LAMBORGHINI Countach’s DTP ratio was 3,929/375 =  10.48

The super car of super cars at the time.  Everybody’s dream.  The most exclusive, most expensive, no-money-spared, latest-in-technology, ultimate-engineering sports car.  All that extraordinary effort, exclusivity and a price to match to just barely beat, by a puny 2.8%, HONDA CB550’s displacement to power ratio of 10.88.

OK, enough about cars of the 1970’s. What about motorcycles?  Isn’t  bikes what this is all about? Not really, since we were talking car-motorcycle analogies to begin with but, what the hell, let’s do motorcycles as well.

In 1973 NORTON put a new engine in their famed NORTON COMMANDO.  It had a displacement of 828 cc which put out an impressive 58 HP.  A DTP of 14.28. Not even close.

Ditto for BMW whose 498, 598 and 748 cc engines produced 32, 40 and 50 HP with DTP’s of 15.56, 14.95 and 14.96 respectively.  Even the highly desirable R90/6 with its 898 cc engine producing 67 HP didn’t come close with its DTP ratio of 13.4.

And ditto for Harley Davidson whose 1338 cc FLH 80 engine produced a maximum of 70 HP.  A DTP ratio of 19.11.  The Sportster and Roadster V-twin 998 cc engines coming out a little later and developing 55 HP had a DTP ratio of 18.14.

Even the ultimate DUCATI at the time, the 900 SS, the bike that gained notoriety in 1976 with its impressive top speed of 144 MPH, couldn’t beat HONDA CB550’s displacement to power ratio. It sported an 864 cc engine developing an impressive 65 HP for a DTP ratio of 13.29.

MOTO GUZZI’s 499 cc engine used on the Falcone Sahara model produced 27 HP for a DTP ratio of 18.48. Their 1975 850T model fared much better.  It had a displacement of 844 cc and produced 58 HP for a DTP of 14.5. This was further improved ten years later (1984) in the 850 Le Mans III models employing the same size engine but now putting out 76 HP for a very impressive DTP of 11.11.

And so on.

Who would have known?  The HONDA CB550.  So many of which are still rotting in barns and backyards by the thousands.

Did you know?

And, finally, as promised,  let’s take a look at the PORSHE of today: the new 911 Carrera, which was unveiled in 2011.


It featured a 3,436 cc engine putting out 345 HP.  A  DTP ratio of 9.96. Very, very impressive, indeed!  And kudos to PORSCHE.  Deservedly.

But this fact remains:

It took Porsche almost 40 years to produce a 911 car, starting at $90,000, which finally beat HONDA CB550’s displacement to power ratio of 10.88. Did you know that?

Did you know that some of the best car engineers in the world struggled for nearly 40 years to produce an exclusive and expensive naturally aspirated engine employing fuel injection, computerized engine management and various proprietary and unthinkable in the 1970’s technologies, materials and techniques that finally beat HONDA’s run-of-the-mill CB550 in terms of displacement to power ratio by…9%?

You did. Great.  Drop me a line using the button below please and I’ll make good on my promise.  I hope you do.



P.S. I appreciate that engine comparison is a complex process and there is no single specification or “yardstick” that could be used reliably. I also appreciate that we tend to get passionate about engines and their power.  And I acknowledge that a smaller engine tends to have a better DTP, and that comparing a 544 cc engine to 800 cc engines or to 3,000 cc engines is perhaps unfair.  However, the point I made about BLACKSQUARE and the 2014 PORSCHE Carrera 911 appears to be valid in general terms.  The PORSCHE car uses 10 cc to produce 1 HP.  The HONDA CB550 uses 10.9 cc to produce 1 HP. PORSCHE’s 345 “horses” move a weight of approx. 3,500 lbs. (including a driver) which means the car uses 1 HP to move a little over 10 lbs. of weight.  BLACKSQUARE’s engine uses 10.9 cc to produce 1 HP.  Its 50 HP move a weight of 550 lbs. (including rider), which means the bike uses 1 HP to move 11 lbs. of weight.  That’s close enough for me.

Put a passenger in the PORSCHE and then BLACKSQUARE and the 911 Carrera become a perfect match.  From power to weight perspective, and from that perspective only, of course.

NOTE: Power to weight ratio is another yard stick for comparing engines. It is defined as the maximum power output of a “machine” divided by its weight.  For example, a 2010 TOYOTA PRIUS is reported as having a power-to weight ratio of 31 lb/hp, which is, of course, backwards and should be actually reported as 1 hp/31 lbs (1 hp for every 31 lbs of weight) instead.  The weight-to-power ratio of a Koenigsegg One:1 is reported as 2.15 lb/hp and the power-to-weight ratio of a Kawasaki H2R Motorcycle is reported as 1.45 lbs/hp.  It appears that in such “who’s best” lists no allowance is made for the weight of the rider/driver or passengers and/or cargo. If we were to stick to such a definition, it would appear that BLACKSQUARE’S 7.5 lb/hp is far superior to PORSCHE’S 9.6 lb/hp, but we all know that for all practical purposes this is purely academic since what matters in the end is riding the bike or driving the car, and for this we would need to consider the TOTAL WEIGHT that the “machine” can move.