new 103's
Road Warrior
Joined: Nov 2009
Posts: 1,635
Likes: 13
From: 501
A 103 is a change in cubic inch displacement. That's all!
All a cam does is control how much air and fuel gets in and out of the motor through its placement of the lobes of the cam.
the cam is also considered the heart because of this. I plan on doing a 103 build when mine is paid off, but I will most likely leave the cams alone. I like longevity and smooth running. I'm sure you have heard the rump,rump, rump of a cam in a motor. This is the same thing. You cam a motor to get more into and out of it through timing, which relates to where on the cam the lobes have been ground onto it.
good enough?
aka Bob
All a cam does is control how much air and fuel gets in and out of the motor through its placement of the lobes of the cam.
the cam is also considered the heart because of this. I plan on doing a 103 build when mine is paid off, but I will most likely leave the cams alone. I like longevity and smooth running. I'm sure you have heard the rump,rump, rump of a cam in a motor. This is the same thing. You cam a motor to get more into and out of it through timing, which relates to where on the cam the lobes have been ground onto it.
good enough?
aka Bob
Road Master
Joined: May 2010
Posts: 910
Likes: 1
From: Charleston, SC
Just by changing the cylinder you can increase the cubic inch displacement so that would be considered the bottom half of your engine including the cylinders, pistons and crank shaft. The cam is part of the top end witch is your cam and valves in the heads. The lobes on the cam opens and closes the valves so changing the cam gives you more lift keeping the valve open longer increasing intake and exhaust timing but nothing to do with displacement. hope that helps some.
Road Master
Joined: Feb 2010
Posts: 791
Likes: 1
From: The Real World
A 103 is a change in cubic inch displacement. That's all!
All a cam does is control how much air and fuel gets in and out of the motor through its placement of the lobes of the cam.
the cam is also considered the heart because of this. I plan on doing a 103 build when mine is paid off, but I will most likely leave the cams alone. I like longevity and smooth running. I'm sure you have heard the rump,rump, rump of a cam in a motor. This is the same thing. You cam a motor to get more into and out of it through timing, which relates to where on the cam the lobes have been ground onto it.
good enough?
aka Bob
All a cam does is control how much air and fuel gets in and out of the motor through its placement of the lobes of the cam.
the cam is also considered the heart because of this. I plan on doing a 103 build when mine is paid off, but I will most likely leave the cams alone. I like longevity and smooth running. I'm sure you have heard the rump,rump, rump of a cam in a motor. This is the same thing. You cam a motor to get more into and out of it through timing, which relates to where on the cam the lobes have been ground onto it.
good enough?
aka Bob
Last edited by harleyriv; Aug 18, 2010 at 07:26 PM.
Grand HDF Member
Joined: Jun 2008
Posts: 4,012
Likes: 298
From: Central Fl
A 103 is a change in cubic inch displacement. That's all!
All a cam does is control how much air and fuel gets in and out of the motor through its placement of the lobes of the cam.
the cam is also considered the heart because of this. I plan on doing a 103 build when mine is paid off, but I will most likely leave the cams alone. I like longevity and smooth running. I'm sure you have heard the rump,rump, rump of a cam in a motor. This is the same thing. You cam a motor to get more into and out of it through timing, which relates to where on the cam the lobes have been ground onto it.
good enough?
aka Bob
All a cam does is control how much air and fuel gets in and out of the motor through its placement of the lobes of the cam.
the cam is also considered the heart because of this. I plan on doing a 103 build when mine is paid off, but I will most likely leave the cams alone. I like longevity and smooth running. I'm sure you have heard the rump,rump, rump of a cam in a motor. This is the same thing. You cam a motor to get more into and out of it through timing, which relates to where on the cam the lobes have been ground onto it.
good enough?
aka Bob
I would strongly suggest a cam change as opposed to more cubes. You will pick up more HP and TQ for far less money. A race tuner would be a good idea as well as some dyno time. Just a suggestion.
Banned
Joined: Jul 2009
Posts: 911
Likes: 0
From: KY
Just by changing the cylinder you can increase the cubic inch displacement so that would be considered the bottom half of your engine including the cylinders, pistons and crank shaft. The cam is part of the top end witch is your cam and valves in the heads. The lobes on the cam opens and closes the valves so changing the cam gives you more lift keeping the valve open longer increasing intake and exhaust timing but nothing to do with displacement. hope that helps some.
http://www.harley-davidson.com/gma/g...bmLocale=en_US
Last edited by JerryL....; Aug 19, 2010 at 06:46 PM.
Road Master
Joined: May 2010
Posts: 910
Likes: 1
From: Charleston, SC
ok I guess I stand corrected I was thinking in terms of a car engine
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Road Warrior
Joined: Jul 2009
Posts: 1,745
Likes: 1
From: A house.
So these explanations confuse me. Simply put, cubic inches (103 vs 96 etc) is determined by cylinder bore and piston stoke. A cam determines valve lift and duration, or how high and how long a valve stays open.
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