103 heads and jugs
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5th Gear
Joined: Dec 2017
Posts: 9
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From: Virgina
103 heads and jugs
i just got some stock heads and jugs off a 2012 103 softail with only 3000 miles on it. 2 questions. I can just buy some pistons and stick these on my 07 flht and what’s the difference besides bore in the 96 and 103 motor in those years?
Tourer
Joined: Jul 2017
Posts: 310
Likes: 58
From: UAE
Yes you can
_______________Bore Stroke
Twin Cam 88 3.750 4.000
Twin Cam 96 3.750 4.374
Twin Cam 103 3.870 4.374
Twin Cam 110 4.000 4.374
Twin Cam 113 4.060 4.375
Twin Cam 120 4.060 4.625
Wrist pin size ID: 0.925
_______________Bore Stroke
Twin Cam 88 3.750 4.000
Twin Cam 96 3.750 4.374
Twin Cam 103 3.870 4.374
Twin Cam 110 4.000 4.374
Twin Cam 113 4.060 4.375
Twin Cam 120 4.060 4.625
Wrist pin size ID: 0.925
Last edited by TomCop; May 14, 2018 at 10:10 AM.
Club Member
Joined: Mar 2016
Posts: 11,687
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From: Clearwater, Idaho
Thinner gaskets are fine to raise the compression a bit. 0.030" gaskets will bring you up close to 10:1 assuming chamber volumes and piston deck height is optimum. If you do this, you might consider what grade of gasoline you normally have available. One other thing: if you have the matching pistons for the jugs and know which pistons go with which cylinders, I would simply break the glaze on the cylinders, install new rings, and run the existing pistons, assuming they still look good.
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5th Gear
Joined: Dec 2017
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From: Virgina
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Club Member
Joined: Mar 2016
Posts: 11,687
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From: Clearwater, Idaho
You might want to zero deck your pistons and take an additional 0.010" off the heads with that cam's intake closing. OR go back to your original plan-- new domed pistons to get that C.R. up a bit more.
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Thread Starter
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5th Gear
Joined: Dec 2017
Posts: 9
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From: Virgina
What do you think about KB performance forged pistons 3.875 bore 10.1? I know i should get the jugs fit to pistons but do you think I can get away with just sticking them in a standard 103 bore?
Club Member
Joined: Mar 2016
Posts: 11,687
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From: Clearwater, Idaho
As long as your cylinders are within tolerance (WITH torque plates) after breaking the glaze, you would probably be ok. I would not buy aftermarket pistons with this in mind without checking to make sure your cylinders mike within tolerance first.