Rebuilding The FXR Evolution Engine

hen Heather and Chris offered me the opportunity to be a part of this year’s Dennis Kirk Garage Build, I jumped at the chance. w

When they told me they wanted me to build the engine, I was doubly honored. In my previous life, my friends and I street-raced Mustangs,

Camaros, Nova’s, and Malibu’s with little or no substantial financial resources. Back then, everything we did was done out of our garages or in our driveways. During the winter we borrowed spaces heated with a wood-burning stove or a kerosene space heater. These are some of the fondest memories I have. The garage is where some of the best ingenuity is discovered. With necessity comes trial and error. Garage Builders worldwide benefit from the time spent trying to make chicken salad out of what some would call chicken shit.

The engine for the Dennis Kirk Garage Built FXR is going to be based on Harley Davidson’s Evolution.

Article And Photos By: Jason Hallman

Produced from 1984 through 2000 (FXR Only), the “EVO,” as it is commonly referred to, is considered by many to be the most venerable engine Harley has ever produced. Because of its similar footprint to all big twin engines produced from 1936 through 1999 (except Touring and Dyna) and its massive availability of aftermarket parts, many refer to the EVO as the “small block Chevy” of Harley engines. Available in many sizes and configurations, from 80 cubic inches all the way up to 151 cubic inches, the EVO is easily considered the perfect engine to represent the best opportunity a “Garage Build” would offer the average garage builder using an average mechanical aptitude and average hand and power tools.

Cycle Stop USA is known locally for producing fully restored engines from the crankshaft pin all the way to the last nut and bolt. Based on your budget and your desired outcome, we can build anything from a Knucklehead to the new Milwaukee 8 engine. For this build, Chris gave me full reign to tap into my inner “garage builder” and build exactly the type of engine I would have built for myself, given the limitations most of us have in our home garages. Now this by no means, means that I will not be thorough. In fact, I intend to touch on all of the pertinent tips and tricks that I have learned and show you just exactly how you can build a killer running EVO on a budget with a few friends, a few tools, and (if you are like my friends and I) a few beers. Any tools I use along the way will be illustrated and any tools deemed “specialty” will be included too. I will do my best to only use tools that you (or a friend) would have access to.

Just because your engine parts may be used doesn’t mean they aren’t any good. In fact, if you spend the time, a “seasoned” part can last just as long as a brand new one.

The cam in this engine was already upgraded to an Andrew’s EV27. The EV27 is considered one of the best choices from an aftermarket camshaft. Jim’s lifters were already in the Dennis Kirk Garage Build engine. We will take them apart and clean them before we pump them back up with fresh oil.

The V-Thunder adjustable pushrods will be cleaned up and checked for straightness. If they pass our inspection, another $170 will be saved for something else the engine could need. The Keith Black pistons were part of the original engine that came with the donor bike. After a quick trip into the Vapor Honing Technologies cabinet, they cleaned up perfectly. If you look very close, you can see where the rear cylinder had experienced detonation. The pistons are still in excellent condition with no scoring to speak of on the skirts, so they will work fine.

Once we determined that the pistons were a “GO” we needed to hone the cylinders. Now…you may not have immediate access to a ball hone, but we purchased one on Amazon for less than $100, and while you would

likely use a drill motor in your home garage, we used our engine lathe to hone the cylinders to make way for the new rings we will install on the pistons.

When honing the cylinders, I like to use the same oil that will be used for engine break-in. For this goround, we used Twin Power’s 20w50 conventional oil.

The same Twin Power oil was used to prep the ball hone prior to honing the cylinder. The instructions were simple, and the jugs turned out great. We lubricated the ball hone using the Twin Power oil before honing the cylinder. Lubrication is critical to achieving the correct “cross hatch” in the cylinders.

Moving the cylinder in and out with the correct speed ensures a consistent finish. The new “cross hatch” will seat the new rings fitted to the pistons and make certain our compression stays in the cylinder to make as much power and torque as possible.

The ball hone instructions call for 60-120 strokes a minute with no more than 500 RPM on the ball hone. When finished, you should have a 45-degree cross hatch in the cylinders to provide your new rings a clean surface to break in on. NEVER REUSE RINGS ON A NEW HONE! Here, you see the finished product. The cylinder cross hatch is consistent, and the surface is prepped correctly. Make sure you use hot soapy water to wash the cylinders and wipe them with engine oil before final assembly

So now the cylinders and pistons are ready to go, as are the cases, oil pump, and external engine covers. Our powder coating turned out perfect on non-perfect parts because we properly prepped them. That is the number #1 takeaway for a Garage Build like this. If an ounce of prevention is worth a pound of cure, then an hour of prep should be worth 30,000 miles + on an engine build. Remember this too; just because someone purchases a pile of brand-new engine parts does not mean that they won’t have to make them fit properly. Most engine parts, even used ones, will last a very long time (even in extreme conditions) if they are adequately prepped for the type of abuse they will see during regular use. The fact that they aren’t brand new is not the most limiting factor. Things like detonation, improper break-in, or improper oiling (especially on initial start-up) are of far greater importance regardless of the age of the parts. When you invest time instead of just money, your outcome will be infinitely better, your engine will last longer, and it will [usually] make more power too. There will always be a point when enough is enough, but the more attention you place on the smaller, more nuanced details, the better off you will be in the long run. When all is said and done, this EVO will have a new valve job, rings, cylinder hone, a performance cam, lifters, and S&S Super carburetor with a performance ignition system and will power this FXR perfectly for many many, trouble-free miles.