Cubic Inches, Stroke, Saddle Height?
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Cubic Inches, Stroke, Saddle Height?
In order to educate myself, I would like for you all to inform me about increased cubic inches (CI) and engine height relationship.
Does Harley-Davidson maintain the square of the engines as the CI increase? Or do the larger bore engines tend toward oversquare? Or is the stroke increased to maintain the HD stroke to CI. (I am assuming that HD factory engines are undersquare?)
Comparing an 80 CI to a 114 CI, is the overall height of the engine different?
Does this increase the saddle height from the ground?
Does Harley-Davidson maintain the square of the engines as the CI increase? Or do the larger bore engines tend toward oversquare? Or is the stroke increased to maintain the HD stroke to CI. (I am assuming that HD factory engines are undersquare?)
Comparing an 80 CI to a 114 CI, is the overall height of the engine different?
Does this increase the saddle height from the ground?
Last edited by Evo-Wes; May 28, 2024 at 11:00 AM.
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From: Colorado
I appreciate your response, but could you elaborate?
Is the stroke also increased with the cubic inch increase, so as to maintain the undersquare?
Or does the increase CI cause the undersquare to drift toward square?
Is the stroke also increased with the cubic inch increase, so as to maintain the undersquare?
Or does the increase CI cause the undersquare to drift toward square?
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The bore is the diameter of the cylinder
The stroke is made with the crank shaft and/or connecting rods.
The cylinder height doesn't change.
Same frame = same seat height. They don't make different frames for different engine sizes.
96" is a bored 88"
103" is a stroked 96" or stroked and bored 88"
I don't know all the geometry and math involved. I'm an electrician, not a mechanical engineer.
The stroke is made with the crank shaft and/or connecting rods.
The cylinder height doesn't change.
Same frame = same seat height. They don't make different frames for different engine sizes.
96" is a bored 88"
103" is a stroked 96" or stroked and bored 88"
I don't know all the geometry and math involved. I'm an electrician, not a mechanical engineer.
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There are many Harley engines from 1985. 80, 88, 96, 103, 107, 110, 114, 117,123. You will need to look at the specifications for all those configurations as they are different pistons, strokes, cams and EFI programming.
That is just for stock Harley engines. Not the many aftermarket configurations available.
The 114 is a "stroker" motor 4.0 x 4.5 inches and I like my 2019 114 in my FLHTP. Google the different Harley engines for the bore x stroke specifications.
Last edited by Goose_NC; May 28, 2024 at 12:22 PM.
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Right, notice the exhaust port location never changed from EVO thru all the T/C variants.
Last edited by djl; May 29, 2024 at 04:20 PM.
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Good information. Thanks.
I am understanding that stroke changes with the CI increase.
And I am also assuming that Harley-Davidson maintains the same engine height by relocating the wrist pin location on the piston (in relation to the head of the piston) to keep the piston from hitting the head.
And that they also shorten the piston length so that they can keep the same cylinder length.
And that the throw of the crankshaft increases to increase the stroke.
My curiosity is greatly aided by your replies. I will now start researching the various engines as you have suggested.
(By the way, mechanical engineers deal with very many other varied fields beside ICE engines.)
I am understanding that stroke changes with the CI increase.
And I am also assuming that Harley-Davidson maintains the same engine height by relocating the wrist pin location on the piston (in relation to the head of the piston) to keep the piston from hitting the head.
And that they also shorten the piston length so that they can keep the same cylinder length.
And that the throw of the crankshaft increases to increase the stroke.
My curiosity is greatly aided by your replies. I will now start researching the various engines as you have suggested.
(By the way, mechanical engineers deal with very many other varied fields beside ICE engines.)
Last edited by Evo-Wes; May 28, 2024 at 01:25 PM.
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