Hi everyone. Im sure this has been beat to death but I recently came into a stock 103 I want to build into a 124ci for my 2013 FLHX me too bike. It's pretty much my daily driver so I'm going for something fun yet bulletproof. I've already bought a Fueling cam chest kit I was going to put in my current 103 but decided to save it for the 124 build. I've been doing some research but keep seeing conflicting parts info or I'm just sucking in too many exhaust fumes to understand?? I know I have to get the case bored for the bigger 124 jugs. Looking at crankshafts Ive read I need a 4 5/8 stroke and to get a set of 110 heads. What pistons and cams would be recommended? Open to mean and helpful info and shenanigans. Does this look like a rash to you? It itches and smells funny

 

By the time you are done the only thing original to the 103 motor will be the cases. They will need boring and you may want timken conversion.. You'll want the 110 heads ported. At that point wouldn't it be easier to simply buy an SnS 124 motor. You might want to try a hot rod 110 or even 107 instead, using bored stock cylinders.

 

Are your last two sentences your signature? Just noticed it in your two new threads

 

Consider a 117- they have been shown to be reliable as a daily driver, using the shorter stroke but the same bore as the 124s. Rebuild your flywheels if they need it, bore your cases, use the Fueling cam chest pieces, pick a cam that works in your preferred range, clutch/intake/exhaust to match, tune and enjoy!

 

Yeah I was thinking that too, then you can save the heads (still need porting) and the crank.. I guess in both cases you also save the cam cover and rocker stuff.

 

Personally it made more sense $$$ to go crate S&S 124 for my bagger build... I'd be in nearly as much going big with my 103. Warranty and selling my 103 were even more reason to go S&S crate 124. YMMV...

 

I'm reading more and more about the 117 builds and might end up going that route. I would buy a crate engine but if I have an engine I can build up myself I'd rather go that route.