S&S 97ci Big Bore Kit Part 1- Tech

Here's some of the major S&S components Norman ordered to freshen up the heart of his '02 Fat Boy. 97ci Big Bore kit ($725): cylinders, pistons, (and not shown rings, and head gaskets). Norman's bike is carbureted so he picked up an S&S Super E Carb kit ($527.80): carb body, intake manifold, backing plate, hi-flow filter, and the iconic tear drop air cleaner cover. Quickie Push Rods ($196.60). High Performance Hydraulic Tappet Set ($248.35). Push Rod Covers ($127.80). 583 Gear Drive Easy Start Gear Drive Cam Kit ($795). Shotgun Slash-Cut Slip on Performance Mufflers ($403.60).

Here's some of the major S&S components Norman ordered to freshen up the heart of his '02

This past August, a few weeks after Sturgis, we got a call from our friend, Norm, on his way home from a long, winding trip to and from Sturgis. After covering several thousand miles, several breaks-downs, mishaps, and the typical delays one might expect on a three-week trip, Norm called to check in and mentioned he'd heard a weird noise coming from his primary and was going to take it easy and limp it back to our garage where there were the proper tools to check it out. A little while later he pulled up in the driveway and right away we could tell that the noise wasn't coming from the primary, it was coming from the lower cam chest area. Norm mentioned that as he rode, the noise increased and he too noticed that it wasn't coming from the primary.

Norm's bike is an '02 Fat Boy (carbureted) and had just crested the 60,000 mile mark. As we rolled the bike up on the lift we asked him when was the last time he had checked the cam chain tensioner shoes. Norm had this look of deep thought, and replied, "Actually never." Now to his credit, Norm does most of the upkeep and maintenance on his bike and for 60,000 miles he hasn't had any major problems. The bike fires right up and just goes every time he gets on it. Many people out there are the exact same way with their bikes. It's kinda like the dentist. We all know we should go in for regular checkups once every six months, but we usually wait until there's pain or something unexpected happens like getting your front teeth knocked out in a bar fight, before we pay a visit to Dr. Scrivello. But as they say "preventative maintenance, is the best maintenance."

No bueno! This is not how a cam chain tensioner shoe should look. Letting your shoes wear down this bad can lead plastic and metal bits contaminating and possibly interrupting your engine's vital passage ways.

No bueno! This is not how a cam chain tensioner shoe should look. Letting your shoes wear

With the knowledge that the shoes hadn't been inspected, we were pretty sure it was going to be the tensioner shoes. And as soon as we had the pipes and cam cover off we could see that the shoe was definitely worn. As we pulled the shoe away from the chain we could see that the center was completely worn to where it was metal to metal, the chain was running against the arm which holds the shoe in place. That was just the outer shoe, there was the secondary shoe on the backside of the cam plate to inspect as well. Using a flashlight and a small multi-angle, telescoping mirror (like dentists use) we were able to get a peek at the other shoe and noticed it was in worse condition.

Overall it wasn't a very good position to be in because that meant that most likely there was shoe debris and maybe even metal bits circulating which could possibly score other internal parts or get caught up in oil passages and lead to other damage. Aside from replacing the shoes, it also meant making sure there was no debris left behind which meant thoroughly cleaning up the cam chest, checking oil passages, and draining/cleaning the oil tank.

As Norman contemplated his next move, being that his bike was nearly seven years old, and had quite a few miles on it his first thought was to get a new bike with the 96ci engine, but that would mean making monthly payments once again (the '02 is paid off). So the next logical thought was since he was going to have to dig into the cam chest he might as well add some performance in the way of a set of new cams. And since he was going to add cams why not go with a set of gear drive cams, then he wouldn't have to worry about tensioner shoes wearing away. Then Norman figured if he's going to upgrade the lower end he might as well hit the top end too. At this point we interjected and mentioned that we'd heard that S&S was about to release a new big bore kit that would take a 88ci TC to 97ci with no machine work. As expected Norman's eyes lit up.

While an order was placed for the S&S 97ci Big Bore kit as well as some other S&S goodies, Norman took the Fat Boy to his local dealer, Anaheim-Fullerton Harley-Davidson to have them perform all the work. Obviously we hung out at the dealership to snap photos of the install, and check out this hot new kit.

As we said earlier, the 97ci Big Bore kit is a brand new product for S&S. A straight drop in kit, S&S wanted to make increasing your engine displacement a quick and easy process, therefore the setup requires no splitting, boring, or machining of the cases. You can simply replace your stock cylinders and pistons for the S&S setup, bolt on your stock heads and experience great results. The 97ci Big Bore kit is available for '99-06 Big Twins, and a 106ci Big Bore kit is available for '07-and-later Big Twins. S&S offers cylinders in either silver or black powdercoat to match the rest of your engine. The cylinders feature a 3.927-inch bore which according to S&S is the largest bore they feel can safely be used in a cylinder with a stock spigot diameter. While stock cylinders can be bored to fit the pistons in this kit, S&S will only offer the setup with its own cylinders because it is not confident that the stock liner and spigot material is strong enough once bored to accommodate these pistons. S&S says its liners are made up of gray iron with a 40,000 psi tensile strenth and is much stronger than the stock liners. They also told us they use gray iron because it has much better heat conductivity than ductile iron. You can use your stock heads with this kit which would yield a 9.7:1 compression ratio. Best of all, by using your stock heads, you can save a lot of cash. At $725 for the Big Bore kit, it makes it a very economical performance upgrade with results you can really feel.

While you can still run your stock heads, S&S does recommend using its new Easy Start Cams to help make starting the bike easier. Large displacement and high compression can really take a toll on your battery and starter. As you hit the starter button (or however you fire up your bike) the internal engine components begin to rotate and as they do the compression begins to build. Depending on the strength of your starter and battery, you may be able to power through and the bike will fire to life, otherwise it can be a slow arrr...arrr...arrr as your engine tries turn over wearing down your battery and causing your starter to heat up and potentially burn up. Most people have seen or heard of compression releases that are mounted into the cylinder heads. S&S' new Easy Start Cams have the compression releases built into them. Whereas some cylinder head compression releases are push button (manual), the compression releases in the Easy Start cams are automatic and operate via centrifugal force.

Here's how it works. Each of the two exhaust cam lobes have a spring-loaded compression release built into the heel of the cam at the point where the valve would normally be fully closed. The raised lobe of the compression release holds the exhaust valve slightly open at cranking speed and in return releases some of the compression allowing the engine to turn over easier.

Once the engine starts up and the rpm increases the compression release lobe is centrifugally retracted and the engine runs normally with full compression and no performance loss. The cams are available in chain and gear-drive for '99-later Big Twins. S&S offers the cams in three grinds to target three different performance segments. The 551 cam is geared towards low end torque for touring, the 585 has proven itself as the peak horsepower cam, and the 583 is a good all around cam. These were the cams Norman went with, which according to S&S should provide good low-end torque and horsepower he'll feel from 1,500-5,000 rpm.

While we've given you a quick overview of some of the key components that are going to be installed to bring Norman's old Softie back to life, bigger, badder, and better, Anaheim-Fullerton tech Drifty, was hard at work tearing the bike down. Follow up next month, where we pick up from this point and get into bumping up this 88 to nearly triple digit displacement and see what kind of performance gains the S&S 97ci Big Bore kit and other components yield.

Source:
Anaheim-Fullerton Harley-Davidson
(714) 871-6563
harleyfullerton.com

S&S Cycle sscycle.com