engine stroke question
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Road Warrior
Joined: Jun 2009
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From: NYC
engine stroke question
I think I understand this...but just want to throw it out there to confirm.
a 2001 roadking with a 88 twin cam engine has a bore of 3.8 and a stroke of 4.0.
a 2007 ultra with a 96 twin cam has a bore of 3.8 and a stroke of 4.4.
So if I were to upgrade the 96 to 103, the jugs and pistons would have no value on the 88, since moving the 88 to 95, would take the same jugs and pistons that were used to bring the 96 to 103. on the 88, the 103 jugs would bring the bike to 95. The 96 jugs and pistons are basically useless in this senerio.
unless I changed the crank on the 88.
a 2001 roadking with a 88 twin cam engine has a bore of 3.8 and a stroke of 4.0.
a 2007 ultra with a 96 twin cam has a bore of 3.8 and a stroke of 4.4.
So if I were to upgrade the 96 to 103, the jugs and pistons would have no value on the 88, since moving the 88 to 95, would take the same jugs and pistons that were used to bring the 96 to 103. on the 88, the 103 jugs would bring the bike to 95. The 96 jugs and pistons are basically useless in this senerio.
unless I changed the crank on the 88.
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Road Warrior
Joined: Jun 2009
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From: NYC
this bore and stroke stuff gets confusing if you don't pay attention to it. the helicopter mechanic in me would have thought as smaller stroke would have given harley more torque
maybe thats why the 95 is such a kick *** engine.
Seasoned HDF Member
Joined: Apr 2008
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From: Sandpoint, Idaho
Stroke=leverage which =torque
Club Member
Joined: Jun 2007
Posts: 45,429
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From: Bedford UK
You can convert an 88" to 95", using larger cylinders and pistons, but my understanding is they will be different part numbers than those on a 96". I am sure there are some engine specialists out there who can sqeeze a little more out of them. The helicopter mechanic in you can still have more lift-off if you wish!
Road Captain
Joined: May 2011
Posts: 545
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From: California
My 2011 RKC has a 103 w/ a 3.875 bore and a 4.38" stroke. According to the HD website.
To go to a 110 would I simply change out the crank? Giving it a longer stroke?
even though the B&S on the CVO 110 is 4" & 4.38" ?
A 2011 RK has a 96" engine w/ a B&S of 3.75" 4.38". Would you do likewise - change out the crank? - to make it a 103?
By making any of these changes do you need to change the head gaskets and bolts to ones that will withstand the added pressures?
To go to a 110 would I simply change out the crank? Giving it a longer stroke?
even though the B&S on the CVO 110 is 4" & 4.38" ?
A 2011 RK has a 96" engine w/ a B&S of 3.75" 4.38". Would you do likewise - change out the crank? - to make it a 103?
By making any of these changes do you need to change the head gaskets and bolts to ones that will withstand the added pressures?
Last edited by Matt0987; Aug 17, 2011 at 06:38 PM.
Thread Starter
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Road Warrior
Joined: Jun 2009
Posts: 1,943
Likes: 3
From: NYC
My 2011 RKC has a 103 w/ a 3.875 bore and a 4.38" stroke. According to the HD website.
To go to a 110 would I simply change out the crank? Giving it a longer stroke?
even though the B&S on the CVO 110 is 4" & 4.38" ?
A 2011 RK has a 96" engine w/ a B&S of 3.75" 4.38". Would you do likewise - change out the crank? - to make it a 103?
By making any of these changes do you need to change the head gaskets and bolts to ones that will withstand the added pressures?
To go to a 110 would I simply change out the crank? Giving it a longer stroke?
even though the B&S on the CVO 110 is 4" & 4.38" ?
A 2011 RK has a 96" engine w/ a B&S of 3.75" 4.38". Would you do likewise - change out the crank? - to make it a 103?
By making any of these changes do you need to change the head gaskets and bolts to ones that will withstand the added pressures?
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Seasoned HDF Member
Joined: Apr 2008
Posts: 10,135
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From: Sandpoint, Idaho
[QUOTE=Matt0987;8707004]My 2011 RKC has a 103 w/ a 3.875 bore and a 4.38" stroke. According to the HD website.
A 2011 RK has a 96" engine w/ a B&S of 3.75" 4.38". Would you do likewise - change out the crank? - to make it a 103?
No, not the crank, just change the bore to 3.875
A 2011 RK has a 96" engine w/ a B&S of 3.75" 4.38". Would you do likewise - change out the crank? - to make it a 103?
No, not the crank, just change the bore to 3.875
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