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Too much seat time maybe?

ANDYVH

New member
As my bike has now surpassed 150,000 miles of giving me many many hours of riding pleasures and experiences, my mind started to wonder about things internal in the engine, like the pistons. Yeah,...I know,...I need to get a life instead of thinking about wierd crap like pistons zipping back and forth in cylinders. Anywho,....

My 94 R1100RS, has 3.898" diameter pistons (pretty good size) and a piston stroke of 2.776". So my mind got to wandering, "how far have those pistons travelled in 150,000 miles?" 2.776"/12 = 0.231'. So each ONE rev of the engine means each piston has travelled 0.462 feet. No biggie right? But, if I consider an average engine speed of 3,000 RPM over those 150,000 miles, say an avg speed of 45mph, 150,000 miles at 45mph = 3,333 hours (that is a LOT of seat time, .38 year of sitting on the seat!). 3,333 x 60 = 200,000 minutes. So, at 200,000 minutes x 3,000 rev per minutes = 600,000,000 revolutions! HOLY CRAP!! That means, those pistons have travelled 277,200,000 feet in 150,000 miles! That's 600,000,000 times .462'/rev. Or, those pistons have travelled 52,500 MILES in 150,000 miles on the bike.

Ok, doesn't sound that big. But consider, for EVERY single stroke of the piston, at 3,000 rpm, that piston comes to a FULL stop at the top of each stroke, reverses direction, accelerates to 925.33 feet per second at mid-stroke, and then comes to a complete stop again at the bottom of the stroke. Reverse direction again, and accelerate again to 925.33 feet per second. And it'll do this all day if I want it to. To me, its simply amazing that the engine has lasted this long, and it'll go MUCH longer yet, day in, day out, hot, cold, whenever. And I have heard reports from BMW techs of engines they have torn down with miles like this, to still see the machining cross-hatching marks in the cylinders!!

Ya know, when a geeky engineer mind starts to wander, all manner of strange thoughts congeal in the ol' pink jello between my ears. Maybe I should get cable TV and quit thinking like this. Or,.... get a date..........

Hmm,...now 0.38 year of sitting on the seat, is like sitting there for 4.56 months! So if done without a break, my butt would be on that seat, in total, from, say June 1st to about October 20th. I need a life!! No actually, I need to ride MORE!
 
Do yourself a favor: don't ever think about anything to do with your heart. Or your kidneys. Or your brain for that (pink) matter. :D
 
Ever have one of those days when you wake up, hear a song on the radio, and then can't stop humming and singing it all day... you know, like

In-a-gadda-da-vida,honey
Don't you know that i love you?
In-a-gadda-da-vida,baby
Don't you know that i'll always be true?
 
So,......maybe I should be thinking of classic rock tunes in my head instead of calculating piston miles travelled versus months in the saddle?

Hmm,...I'll give that some thought. Here's a catchy little diddy to hum in your helmet:

http://www.youtube.com/watch?v=9HeEFxgktVg

Ya know, I think all those years of watching Monty Python may have had some effect on me.
 
I got a headache reading that! On the bright side, I'm presently drinking a gin and tonic to cure it. :bottle
 
someone is gonna.....

You know someone...somewhere....is gonna come up with an online "Piston DistanceTraveled" calculator...where all you do is enter the relevent numbers...and voila!!! All these neat facts will jump out at ya!!

Believe me.. I work with a guy who thrives on developing this kinda stuff:scratch
 
"You know someone...somewhere....is gonna come up with an online "Piston DistanceTraveled" calculator...where all you do is enter the relevent numbers...and voila!!! All these neat facts will jump out at ya!!

HA!! A new Iphone app I could claim! Useless but strangely relevant.


Perhaps all this explains why I favor Whiskey Manhattens?

I mean, if I build up my brain cells (mental workouts) with this kind of wacky cranial manipulation, aren't I entitled to kill off the weak ones?

Survival of the fittest is my rationale!

I recall, once, at a Badger football game at Camp Randall in Madison, as we walked to the stadium, we saw students atop a two story building with a large funnel and 1" ID long hose down to the street below. They were prompting others to partake in a gravity enhanced beer bong. The lucky(?) participant would put the hose in the mouth, tip the head back, and two stories up, a beer is poured down the hose. I told my wife, "See? That's what happens when beer is accessible to engineering students!"
 
So, imagine if you could view the engine from above while the bike was in motion, and you could see the pistons moving in and out. If there were a point of light on the end of a piston, and you could take a time-lapse photograph of that light, what shape would it be? In other words, plot the motion of the piston on a time/distance graph. Would it be a smooth sinusoidal motion, or something far more spikey?

Also, should you include the forward (bike-wise) motion of the pistons along with the lateral (piston-wise) motion for a sum total of distance traveled by the pistons?

Dangit, man, you've made me start thinking...:scratch
 
Actually, I did think of this while riding. To me, our modern internal combustion piston engines are a marvel of power and durability. Not that I obsess about those pistons flailing about, but it does baffle me that they can last like they do, for as long as they do, all at the push of a button. Amazing.

To me, it gives cause to have a lot of respect for these marvelous machines we enjoy all because of some internal good bits doing what they do so well. Sure, they get a lot of flack for being so inneffecient, turning only about 15% of the total energy per gallon of gas into actual thrust. So much is lost to friction and heat. Ahh,...but what glorious thrust it is.

S'cuse me, getting a little teary eyed here.
 
Damn it, me too. My flippant earlier comment aside, consider the stress not on the pistons, but rather on the connecting rods. They are taking the full force of moving and stopping the piston during each stroke (well, actually transmitting the force to the crankshaft, but same idea). Ok, so let's figure each piston weighs x at rest. I don't happen to have an 1100 piston laying around, but I do have an old piston from my Honda GB500 thumper. It weighs about a pound and is approximately 3.75" in diameter, so is probably fairly comparable. If we solve for the Kinetic Energy at this weight, given 925.33 feet/sec (K=1/2 mv2) (and we're not even including the weight of the connecting rod, etc.), then the Kinetic Energy on every stroke as transmitted through the connecting rod is approx 18040.93 joules, or 13306.31 ft/lbs. Another "HOLY CRAP" is appropriate here...
 
Your exercise reminded me of an engineering "study" we did as freshmen students at Purdue back in the 70's. It had to do with the total distance, also in a reciprocating motion, traveled by a particular item of male anatomy over a weekend by the entire male student population of West Lafayette. It was an astounding distance as I recall...

We later refined the data to differentiate between a common, run of the mill weekend, and a "Game Day" weekend.

We were still using "Slip-Sticks" at the time.
 
Your exercise reminded me of an engineering "study" we did as freshmen students at Purdue back in the 70's. It had to do with the total distance, also in a reciprocating motion, traveled by a particular item of male anatomy over a weekend by the entire male student population of West Lafayette. It was an astounding distance as I recall...

We later refined the data to differentiate between a common, run of the mill weekend, and a "Game Day" weekend.

We were still using "Slip-Sticks" at the time.

And the data analysis revealed.......:scratch


Probably need to discuss methodology so we can validate the claims. Peer review you know.... :hungover
 
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