Building a 117 Twin Cam
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Road Captain
Joined: Sep 2012
Posts: 626
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From: Mo
Building a 117 Twin Cam
I have a 2013 Electra Glide. Right now it has 255 cams, Harley ventilator air breather, S&S head pipe (2-1-2), Jackpot mufflers and a Power Vision tuner. It was tuned years ago by Jamie at Fuel Moto. I have been considering building it into a 117 this winter. I mostly just ride it, sometimes aggressively but don't usually twist the crap out of it. So now goes the questions.. I plan to have the crank trued, plugged and welded but in a mild build is the Timken bearing mod necessary or will the Harley lefty bearings in both positions work? I obviously will send the cases out to be bored for the bigger cylinders. I assume the compression needs to be in the area of 10.5-1? Is there an advantage of going with aftermarket heads or will the stock heads be ok with a proper porting job and bigger valves? I will obviously need to get different cams are there any recommendations? Do I also need to go with a larger throttle body and injectors? I don't mind spending the money for what ever I need but I don't want to waste money either.
HDF Community Team
Joined: Jun 2006
Posts: 12,776
Likes: 2,607
From: san antonio
If you plan to turn the wrenches yourself, you need to outsource the machine work, i.e., Hoban Brothers for crank (for a 117" motor, do the Timken conversion), headwork and piston/cylinder fitment. Hoban Brothers will need to know what cylinders will be used for the case boring. Consider talking Scott/Hillside Cycles and Kirby/VeeTwin Performance about the services and "packages" they offer and move forward with whoever is closest or you feel comfortable with as both are pros. Whoever you choose will work with you to develop a build plan and will provide better input than you will get from asking questions here.
Once you start turning wrenches, there is plenty of help here should you have questions related to assembly, etc. You will need the service manual for your bike.
Once you start turning wrenches, there is plenty of help here should you have questions related to assembly, etc. You will need the service manual for your bike.
Banned
Joined: Sep 2009
Posts: 3,569
Likes: 624
From: deland,florida
yes the "lefty" bearing will work but a timken set up will provide much more stability to the lower end,depending on what power your looking for,OEM heads can be ported to work OK but we like using our stage II CVO 110 heads on 4.125" bore builds here,
HDF Community Team
Joined: Apr 2018
Posts: 2,574
Likes: 1,068
From: Ohio
I have a 2013 Electra Glide. Right now it has 255 cams, Harley ventilator air breather, S&S head pipe (2-1-2), Jackpot mufflers and a Power Vision tuner. It was tuned years ago by Jamie at Fuel Moto. I have been considering building it into a 117 this winter. I mostly just ride it, sometimes aggressively but don't usually twist the crap out of it. So now goes the questions.. I plan to have the crank trued, plugged and welded but in a mild build is the Timken bearing mod necessary or will the Harley lefty bearings in both positions work? I obviously will send the cases out to be bored for the bigger cylinders. I assume the compression needs to be in the area of 10.5-1? Is there an advantage of going with aftermarket heads or will the stock heads be ok with a proper porting job and bigger valves? I will obviously need to get different cams are there any recommendations? Do I also need to go with a larger throttle body and injectors? I don't mind spending the money for what ever I need but I don't want to waste money either.
Road Master
Joined: Oct 2017
Posts: 815
Likes: 292
From: Uptown Bay Area, Cali
I have a 2013 Electra Glide. Right now it has 255 cams, Harley ventilator air breather, S&S head pipe (2-1-2), Jackpot mufflers and a Power Vision tuner. It was tuned years ago by Jamie at Fuel Moto. I have been considering building it into a 117 this winter. I mostly just ride it, sometimes aggressively but don't usually twist the crap out of it. So now goes the questions.. I plan to have the crank trued, plugged and welded but in a mild build is the Timken bearing mod necessary or will the Harley lefty bearings in both positions work? I obviously will send the cases out to be bored for the bigger cylinders. I assume the compression needs to be in the area of 10.5-1? Is there an advantage of going with aftermarket heads or will the stock heads be ok with a proper porting job and bigger valves? I will obviously need to get different cams are there any recommendations? Do I also need to go with a larger throttle body and injectors? I don't mind spending the money for what ever I need but I don't want to waste money either.
Either S&S or Darkhorse crank and rods
Timkin conversion
Port your existing heads
TB
TTS Tuner
Professional dyno tune
Dave
I did a similar build a few years ago. 117" with S&S cylinders, Darkhorse trued/pinned/welded crank with their forged rods, and Timken bearings, ported stock heads with oversized valves by WFOLarry. I used a Screamin' Eagle 58mm throttle body with 5.3 injectors and S&S 585 cams. Dyno'd 128hp @ 5750RPM/138tq @ 4200RPM. I'm sure more aggressive cams would have made more peak power but I was more interested in a broad torque curve, so the 585s were recommended to me and I'm really happy with it. Mine's in a Dyna, which is considerably lighter than your Electra Glide, but I think it would still be a good setup. There's definitely faster bikes out there, but this one still gets my attention when I grab a handful of throttle.
My recommendation -- Pick a reputable head porter, tell them your goals, and let them recommend a cam.
My recommendation -- Pick a reputable head porter, tell them your goals, and let them recommend a cam.
Stage III
Joined: Mar 2024
Posts: 4
Likes: 0
From: Garden Grove CA
This is exactly where I want to be at! I just did a 117 I sent my heads out to Dave Mackie and did their 598 cam did the Darkhorse bottom end with the Timken bearing conversion a bunch of other stuff but very disappointed on the turn out only made 114hp and torque I dont know what I have to do. I dont know what the compression is at I am guessing 10:1 but not sure.
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HDF Community Team
Joined: Jun 2006
Posts: 12,776
Likes: 2,607
From: san antonio
This is exactly where I want to be at! I just did a 117” I sent my heads out to Dave Mackie and did their 598 cam did the Darkhorse bottom end with the Timken bearing conversion a bunch of other stuff but very disappointed on the turn out only made 114hp and torque I don’t know what I have to do. I don’t know what the compression is at I am guessing 10:1 but not sure.
BTW, this thread is three years old; suggest you start a new thread with complete details of the build. Check out BigBoys compression calculator for the details you need to provide along with throttle body size, chamber volume, exhaust, etc.
Last edited by djl; Aug 31, 2024 at 09:56 AM.
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