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Need advice from the wrenching gurus.. S&S 117 Build

5943 Views 24 Replies 8 Participants Last post by  09Sharknose
In addition to my Road Glide I have a 1996 Fatboy. I swapped the original engine for a 2008 S&S 117 EVO. I did head work (Branch O'Keefe) and cams. My bike has difficulty starting at times and often leaves me stranded. I always give the throttle a few pumps and open my enricher before turning it over. The bike chugs before starting. It has a single fire ignition and I often get a backfire that sounds like a gunshot. I'm always able to get if going if I jump start it but that's not a solution to my problem. I'm thinking that I may need a higher torque starter. I don't want to invest in a new starter if that's not the issue. Any advise or thoughts are appreciated.
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You need to wire a double relay for the starter and compression releases assuming you have ACR's. That's what I did on the 124. Starts every time without a problem.
Thanks for the input. Yes, I have ACR's
We've re-built many of the low-compression/emmission S&S 117"s to real fire-breathers. 130/135 are the numbers we like to see prior to calling the customer for pick-up.
Once tuned they start instantly.
Perform a compression test on both cylinders, and a leakdown test would also be benificial.
S&S carb with what jets? Bored? Thunerjetted?
What adjustable ignition was used once the engine work was established?
Happy to help
Super G carb but I don't remember which jets I used. I rejetted a couple of times. I'm using the Thundermax ignition. I did the work a few years ago and I don't remember all the specifics. It was a bear fitting the engine into the FB frame and we took a few short cuts to make things work out. I'm gong to have to look deeper into the specifics.

Find someone with a dial back timing light. Most say a stock Evo should be timed at 35 deg., IIRC S&S suggests 30 deg. for the bigger motors. Check with S&S as it's been a number of years since I had a S&S crate motor. You know! CRS.
Currently timed at 35 degrees. My problem may be as simple as a timing issue. I'm a novice mechanic and most of my experience with with EFI bikes. I got some software from Thundermax but I'm not experienced enough to know how to use it; especially on a carbureted bike.
BDMastiff- would the 117 you put into your fatboy happen to be the stock engine from your mastiff? Just curious....

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Yep, it was from my Mastiff. The Fatboy belonged to a friend who worked at RB Racing. RB used the FB for testing all types of turbos, intercoolers, pipes and other prototypes. My Big Dog was having tons of issues and I was tired of dealing with them; especially since they went bankrupt. My gas tank was actually at their factory in Kansas when they went belly-up and it took my 5 months to get it back.... with no help from anyone. I liked the S&S so I bought the Fatboy minus the engine and sold the Big Dog chassis. My friend did most of the wrenching.

Before the engine swap:


My Big Dog:
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Cool! I thought so! I used to own a BD Mastiff. I got rid of it after having soooooo many electrical problems out of it! Sure wish I still had the engine though! That 117 s&s was a BEAST of a power plant! Mine was a 2006. Funny how almost 10 years later, HD is still using a 103 in most bikes!

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I had tons of electrical problems too. Also, the tank liner peeled out and clogged all my lines. After I pulled the 117 I send it to Branch O'Keefe and ported the heads. I also upgraded the cams. My 117 is now a super beast. It's incredibly torquey almost has too much power for the fatboy. I love it!!!!!
Awesome! Any reason you put the 117 on the fatboy instead of the roadglide?

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My 2013 Road Glide is a CVO with a 110 and it was personally dyno tuned by Steve Cole at TTS. Also, the CVO is an EFI bike and the S&S 117 is an Evo engine. It just made sense to put it in the Fatboy which is a carbuerated bike. Lastly, my 2013 CVO is my favorite of all the bikes I've ever owned so I didn't want to mess up a good thing.
Cool! That engine in a fatboy has to be ridiculously fun! I used to totally destroy Harleys with that thing!
No doubt, the Big Dog was a fun bike when it was running. The electrical problems became too much of an issue and once the tank liner pealed I was done with it. I broke down at least a dozen times and sometimes the bike would just shut down completely while I was riding. The funny thing is that the guys who love Big Dogs are pretty hardcore about it. I rode with some of the guys on the Big Dog forums and they were mostly die hard fanatics.

The Fat Boy is uber fun to ride. I can spin my rear tire while moving so I've gotta pay attention when I womp on the throttle. Also, the bike is lowered 1" so I've gotta watch the corners when riding twisties. I'll probably bring it back up to the standard height.
Yeah I feel ya on the electrical problems! I never had to pay for any of them, but I always had to take it to the shop! The end of the line for me was when it broke down crossing Main Street in Daytona Beach during Bike Week. It was on a Thursday, I was at home on a Road King by Tuesday.

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I never had to pay for the electrical issues either except for the inconvenience of getting trailered home and to the dealer in Harbor City. When it happens a dozen times it gets old very fast. Also, the dealers were the type of guys who would smile and say the right things as the f#*k you in the azz.

Of all the chopper bikes that were being manufactured at one time, Big Dog was actually one of the best, if not the best.
Sheldon Coleman(Coleman Camping Equipment)had/has deeeeeeeep pockets to be able to withstand the ecomonic climate, when the bikes were not selling as well, they did not go bankrupt, they just folded the Big Dog company.
We have one for sale currently in our retail area.
You are correct Sir, they folded. At the time my gas tank was at the factory in Kansas under warranty. They folded and it took me 4 months to get my tank back. I got lucky and a guy who used to work at the factory read my post on the Big Dog forums. He stepped up and helped me get it back. Afterwards, my dealer charged me $1200.00 for the new tank liner since it no longer had a warranty. Their price was a total rip off. None the less, The Big Dogs were the best of the worst when it came to the "custom" chopper bikes. Sheldon Coleman did his best to keep the company going as long as possible.

They may have had the best components, but they were unreliable as hell! Mine was never good for two rides in a row without a repair of some kind. It stranded me multiple times due to chronic electrical problems. I think they replaced the entire electrical system on mine over the period I owned it. That engine was awesome!
I agree with everything you said. The problem with the Big Dogs were the ECU's and all of the electrical components. Many of the guys on the Big Dog Forums rewired their bikes with after market systems in order to make them reliable. I probably could have built a more reliable bike myself for about half the price of what I paid for the Mastiff but I don't have the wrenching skills to do it.
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The battery is only a year old. I tested it and it's strong. Thanks for the help.
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