TECH: S&S 107″ Cam & Cylinder Kit (Intro)
Our Heritage gained 28 hp and 27 ft-lbs. of torque!
Captions and photos by Chris Maida
Harleys are built to cover some serious mileage. But even the most babied engine is going to need a top end rebuild at some point, although readers of this magazine probably don’t fall into that category. When it comes to the world of Harley-Davidson, anything you want to do has a bunch of different options. So when our high-mileage 2012 TC 103 Heritage Softail started hinting at a new top end, we examined a few of the options. The first, of course, is to rebuild it back to stock specs. Option B is to increase the engine’s displacement and throw in a hotter set of cams. Okay, so our only real options were how big and how hot.
Since the still-young Heritage sees lots of time out on the road, reliability and manners are just as important as power output. For that reason, we turned to the legendary S&S Cycle in Viola, Wisconsin, for a 107″ cylinder kit (#910-0479/$929.95) and its gear-driven HP103GE Easy Start camshafts (#330-0354/$824.95). The wrinkle black, 11-fin cylinder kit fits 2007 and later Big Twins. (No worries Twin-Cooled model owners! S&S has a kit for you, too.) The 3.937″-bore cylinders are the largest size that can fit in stock, unmodified engine cases. That means no machining is necessary, and you can achieve the maximum bore size with minimal effort. The S&S cylinders are also the same height as stock, which, again, makes this an easy install. The centrifugal-cast, gray iron liner and the included 4.937″, 4-3/8″ stroke CP pistons provide excellent wear and noise characteristics and performance. The fin area is increased for better cooling performance over stock cylinders. The cylinders are also available in a silver powdercoated finish, which also matches stock H-D engine finishes. The kit includes gaskets and piston rings, wristpins, and wristpin clips.
With the Heritage Softail’s new displacement, a set of performance cams is necessary to get the most out of the Beta motor. The HP103GE Easy Start camshaft is what S&S calls a “horsepower cam.” However, different intake and exhaust systems can turn the engine into more of a torque monster with a bit less top end. These are actually bolt-in cams, so no modifying of the cam compartment is necessary, a recurring theme with this S&S project. Since the heads and rocker boxes were off the bike when we installed the cams, there was no need to even order a set of pushrods; the stock ones slid right back into place! Of course, besides their high-performance profile, these are gear-driven cams. This means no more chain tensioners (great news for this high-mileage rider), but it also means a longer lifespan for the parts, and a more secure connection inside the engine’s bottom end.
For a tuner, we went with TechnoResearch’s Harley-Davidson (Delphi) 2 (#TR200053-M01-U/$638) tuner. We’ve worked with the TR quite a bit on a handful of different bikes, and it delivers flawless tuning every time. The USB port key allows for multiple reflashes on a single motorcycle. Our choice for this build is a TechnoResearch DirectLink Flash Tuner. This module allows you to alter the fuel table, spark advance table, and other calibration table values. You can also get real-time fuel table and spark table cell tracing. The DirectLink (Flash-Tuner) communicates directly to the stock EFI module, so there’s no wiring changes or additional modules to install.
As reliable and easy to install as the S&S Cycle cylinder and cam kits are, they provide some majorly impressive numbers on the dyno. The 103″ Softail’s baseline runs yielded 68.9 hp and 87.6 ft-lbs. of torque. After tuning, the Twin Cam puts out 97 hp and 114.9 ft-lbs. of torque! That’s a 40 percent increase in horsepower and a 31 percent increase in torque. What’s really cool is that the same S&S kits also work on 96″ Twin Cams, delivering the same final output numbers. So if you’ve got a 96-incher, you can expect those percentages to be even higher, which makes your dollar-to-power ratio even higher as well!
When it comes to high-performance Harleys in the New York area, Rosa’s Cycle is the place to go. Andrew Rosa lent his skill and expertise to our S&S-equipped Heritage Softail, and the power numbers speak for themselves. Follow along as he takes us step by step in the accompanying photos and captions to see exactly how the experts do it. AIM
Rosa’s Cycle Shop
S&S Cycle Inc.