Don't Harleys get their "thu-thump...thu-thump...thu-thump" sound because the two pistone are on the same pin on the crank, making cylinder 1 fire, with cylinder 2 firing 90 (or so) degrees later, making it have a 270 degree rotation with no power stroke? I remember readin that on HowThingsWork.com or some shaZam! like that.

I probably didn't describe that very well. But imagine two pistons on on crank pin.

Or maybe it's one piston firing per revolution, but same theory...shaZam!, now I'm confused...


Dave  :dunno:  

OK, here's what I was meaning to explain:

QuoteA Harley engine has two pistons. The difference in the Harley engine is that the crankshaft has only one pin, and both pistons connect to it. This design, combined with the V arrangement of the cylinders, means that the pistons cannot fire at even intervals. Instead of one piston firing every 360 degrees, a Harley engine goes like this:

   * A piston fires.
   * The next piston fires at 315 degrees.
   * There is a 405-degree gap.
   * A piston fires.
   * The next piston fires at 315 degrees.
   * There is a 405-degree gap.

http://auto.howstuffworks.com/question325.htm

"What gives a Harley-Davidson its distinctive sound?"

Heh, I described it to a labmate as sounding like farting in a Jacuzzi.  Very burbly.  Thanks for the link!

Quote from: Roadstergal"What gives a Harley-Davidson its distinctive sound?"

Heh, I described it to a labmate as sounding like farting in a Jacuzzi.  Very burbly.  Thanks for the link!

That's a little more apt; I'll use that one.  

Dave  

Quote from: RoadstergalNope.  The only "naturally" balanced engines are 180 degree twins (BMW boxers), I-6s, and any duplicate of I-6s (V-12s, e.g.).

I'm not very well versed with combustion engine technology/terms but I think the 180-degree twin configuration you are talking about is usually referred to as 'flat'.  For example, the Honda Valkyrie is a flat 6 (to my knowledge), making
its 1.3L engine more powerful than many compact cars and small european nation-states

From what I have heard about the difference between inline and V configured pistons is that considerably more torque is delivered on the low end, delivering much more power to the bike in starts and turns.  The trade-off is considerably less
power at high rpms. I seem to recall someone telling me that V's won't/can't rev as high as inline engines, which lowers
the top attainable speed of a 'v' engine.

Again, I am a relatively uninformed layman, but in practice this seems analogous to how racers set up their bikes to have either a high or a low gear ratio depending on the track and conditions (low ratio = more low end power).  I imagine the physics involved has more to do with the overall moment of the force applied by the pistons being greater due to the staggered angle... but that's just a wild guess.  I'll let an Mech.Eng. who knows engines fill us in

aircraft piston engines...   other than radials.


V-twins    

harley
SV series
TL series

all use a motor that is inline with the bike which makes for a narrow bike

moto guzzi  puts them in sideways.

There are 5 cylinder MotoGP bikes, correct?

Some of the race teams are getting AWAY from Big Bang, correct?

Also, the Suzuki TL is a 90 degree v-twin or 45 degree?  Is the SV 90 or 45?  45 degree v's have more vibration, correct?

Also, I think there is a bike designer in Seattle named John Cyz that is making a production bike that uses a counter rotating in-line 4 so the crank for two cylinders turn clockwise, that the other two turn counter clockwise.

Quote from: Badger

Quote from: RoadstergalNope.  The only "naturally" balanced engines are 180 degree twins (BMW boxers), I-6s, and any duplicate of I-6s (V-12s, e.g.).

Almost all aircraft piston engines are horizontally opposed (180* cylinder pairing).

Are you referring to the rotary engine design... that mazda incorporated into the RX-8?

I have yet to drive one, but I've heard that there is no smoother engine on the face of the earth.

Quote from: TarzanBoyI'm not very well versed with combustion engine technology/terms but I think the 180-degree twin configuration you are talking about is usually referred to as 'flat'.

I've heard flat used to refer to inlines.  It's referred to infrequently enough that I just call it horizontally opposed when I need to refer to it.  BMW's version is called a boxer.

Quote from: TarzanBoy

Quote from: Badger

Quote from: RoadstergalNope.  The only "naturally" balanced engines are 180 degree twins (BMW boxers), I-6s, and any duplicate of I-6s (V-12s, e.g.).

Almost all aircraft piston engines are horizontally opposed (180* cylinder pairing).

Are you referring to the rotary engine design... that mazda incorporated into the RX-8?

I have yet to drive one, but I've heard that there is no smoother engine on the face of the earth.

Nope. That's different. Horizontally-opposed isn't a rotary. I think only Mazda uses it.

Here's another good article I read when I had a big deadline that I wanted to put off

http://auto.howstuffworks.com/rotary-engine.htm

Mazda rotary engines are Wankle engines, and don't use pistons at all.  They use (usually) two rotors that are triangle shaped that create their compression against the outer wall of the engine as they rotate, fire, and move on.  Very high reving.

Wankel.  I make fun of my friend's little Wankel.  They're marvelous engines that make tons of power for their displacement and have very few moving parts to break.  Negatives - lousy fuel efficiency, easily flooded, and early designs had a tendancy to burn oil.

Suzuki made a rotary motorcycle, the RE5.



http://auto.howstuffworks.com/rotary-engine.htm

Thanks for posting that link again.

Quote from: RoadstergalI make fun of my friend's little Wankel.

:lol:

Quote from: 2005-GS500-PDXThanks for posting that link again.

D'oh.  I had a Dave moment.

Quote from: Roadstergal

Quote from: 2005-GS500-PDXThanks for posting that link again.

D'oh.  I had a Dave moment.

Other Dave, I am pretty sure.

Dave  

Quote from: davipumoto guzzi  puts them in sideways.

geez, hasn't anybody told them yet?

There are too many Daves.  I once dated a Dave, was friends with two Daves, and bought a bike from a Dave.


These are the Daves I know, I know
These are the Daves I know
These are the Daves I know, I know
These are the Daves I know

David Hoffman
He works in my dad's store
He's worked here for 12 years
He'll probably work here for more

These are the Daves I know, I know
These are the Daves I know
These are the Daves I know, I know
These are the Daves I know

Dave Gort
I've known since I was six
In grade eight he broke his leg
So we got drunk and sick

These are the Daves I know, I know
These are the Daves I know
These are the Daves I know, I know
These are the Daves I know

Some of them are Davids
[Dave Gort: But most of us are Daves]
They all have their own hands
But they come from different moms

These are the Daves I know, I know
These are the Daves I know
These are the Daves I know, I know
These are the Daves I know

Dave Jadiski
Man, this cat can swing
He weighs almost 50 pounds
And he delivers my paper on time

These are the Daves I know, I know
These are the Daves I know
These are the Daves I know, I know
These are the Daves I know

Dave Capisano
I hardly know him
...
[Bruce stands around, looking vaguely uncomfortable for the rest of the measure]

These are the Daves I know, I know
These are the Daves I know
These are the Daves I know, I know
These are the Daves I know

[Next two measures sung by the Daves Bruce knows: ]
We are the Daves he knows, he knows
We are the Daves he knows
We are the Daves he knows, he knows
We are the Daves he knows

Some of us them are Davids
But most of us are Daves
We all have our own hands
But we come from different moms

These are the Daves I know, I know
[Daves: We are the Daves he knows, he knows]
[All: These are the Daves]

Quote from: indestructibleman

Quote from: davipumoto guzzi  puts them in sideways.

geez, hasn't anybody told them yet?

Valve adjustments are a snap.

Quote from: TarzanBoy

Quote from: Badger

Quote from: RoadstergalNope.  The only "naturally" balanced engines are 180 degree twins (BMW boxers), I-6s, and any duplicate of I-6s (V-12s, e.g.).

Almost all aircraft piston engines are horizontally opposed (180* cylinder pairing).

Are you referring to the rotary engine design... that mazda incorporated into the RX-8?

I have yet to drive one, but I've heard that there is no smoother engine on the face of the earth.

Nope.  Horizontally opposed just means the cylinders are 180* offset...it still works like a conventional engine.  Rotary engines are different.  "Rotax" engines (that's the manufacturer) are used frequently in homebuilts, but I'm not sure if that's the same concept Mazda uses.  Radial engines are also different...they have cylinders arranged in a circle around the crankshaft, and can really only be found on classic aircraft...the engines are typically huge and thus only work well in taildraggers (they have a higher nose posture on the ground that provides better prop/ground clearance).  I'm pretty sure there are no current production radials.