For our Project Pro Am YFZ we built one of the most tricked-out machines we have ever laid eyes on. It starts with our 12 Hours of ATV America Award Winning YFZ and ends by being worthy of winning a pro national!

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A few years back we loaned our 2004 Yamaha YFZ to Kory Ellis, who used it to race the ’04 Pro Production class at the GNC Motocross Series.  With Kory’s and Lone Star's help we determined that it took a little over $7000 to make the ’04 YFZ competitive in the Pro class. We came to the conclusion that Yamaha already squeezed just about every bit of power out of their motor, so you really didn’t need to spend too much time, money and effort in the motor department. Back then we simply let Yamaha’s potent powerplant breath by adding a pipe and tossing the air filter lid -- and it was good to go. Is this still the case as we race into 2006?  

Back in the day, pro setups utilizing a heavily modified 250R engine typically made about 48 horsepower. With the new generation of 450cc four stroke machines, we are now achieving the same numbers by simply bolting on an exhaust, so it’s easy to see why we first thought that high-dollar motors were a thing of the past. In the years since, all of the motor builders in this industry and beyond have turned their attention to further developing the OEM’s new high performance four stroke engine.

Now it’s common to see B class racers pulling to the line with full blown race kits in their motors and a full array of both internal and external modifications. Whether you want to admit it or not, chances are you won’t find a pro motocrosser sitting on the line without extensive internal motor mods. The fact is competition dictates necessity and times have once again changed.

As always, the foundation of any project is critical in achieving one's goal. Our goal was to build a production based race quad that provided a Pro Am rider with enough amunition to contend with a pro-level ATV. All the while, this bad-to-the-bone racer needed to offer more reliablity than the top level pro rider needs. Our choice foundation was simple, Yamaha's YFZ won our 2006 12 Hours of ATV America Shootout hands down by winning every single category. The decision was a no brainer, the YFZ got the nod.

Why the Pro Am class?

SS Motorsports monster Stage 3 motor kit coupled with ITP Holeshot tires turned our YFZ into a real earth-mover. The motor’s power curve is super smooth - making the power explode is as easy as jabbing the throttle.

The Pro Am class bridges the gap between the pros and the amateurs. If you are an amateur looking to run in the Pro Am class, you will need a machine competitive enough to run at the Pro level without sacrificing durability. Recently, there has been a big trend in weight reduction in the Pro class. Titanium springs, bolts, exhausts and carbon fiber parts have found their way on the top pro racer’s machines.

Racing as an amateur is a bit different. Chances are the average Pro Am rider doesn’t have the parts allotment that most pros do, and they’re even less likely to have a highly trained mechanic on hand to take care of their machine. And for the guy living on the amateur side of the Pro Am class, he needs a machine that has the speed to win, and the durability to hold together. And that’s exactly where we wanted to focus our attention for this build. We asked, “What will it take to deliver the Pro Am racer all of the performance available to the pros, yet durable enough to last the whole season?”

From The Ground Up
Since this was going to be a “from the ground up” project, requiring lots of time and attention to detail, we turned to the professionals at Earlywine ATV and Cycle.  Chris Earlywine, also the owner of Earlywine’s Indoor Motocross, is a former GNCC pro racer and has years of experience setting up race quads for himself and his customers. We trusted that he could build our machine right the first time and give us valuable feedback along the way.

A Better Frame

After a hard season of Kory Ellis abuse, our ’04 YFZ was carefully examined. We observed that it had developed some cracks in the frame near the upper stem mounts. Since we were going to pull the motor anyway, and this quad would be abused harder than most, we opted to tear our brand new YFZ down to the frame for some strengthening.

One call to Lone Star Racing and we had a frame gusset kit and six point subframe on the way. Lone Star’s Gusset Kit was extremely complete, filling in many key angles, adding more strength and rigidity to the stock frame. All of the kits plates and tubing were pre cut for proper fit, however we spent several hours machining a lot of the parts in order to make the various plates and tubes line up just perfectly. All in all installing the gusset kit took us several days, but reducing the chances that we will have to tear the machine down early on in the season for a frame swap made the process well worth the effort.

The YFZ's light weight stock subframe is fine for most. Yamaha's Ellis, Spader and Brown even use their stock subframes, but since they replace their race quads evey few months maybe they aren't subject to the abuse that ours will undertake. Yamaha went to great lengths to make the YFZ’s subframe light weight; however the reduction in weight came with a reduction in strength, even when being compared to the stock subframe on the TRX 450. In order to make our YFZ survive repeated hard landings and the moderate unforeseen rollover, we installed a Lone Star chrome plated 4130 chromoly subframe.

Elka’s Pro Series shocks did an outstanding job of floating over or slamming through Echeconnee’s deeply whooped out track. The suspension was spot-on for all but the nastiest hits, like the one seen here where W.L McCarley  attacks this 80ft double. Chris Earlywine thought the suspension was perfect right out of the box, but W.L wanted the rear stiffened a bit. With plenty of adjustment in reserve on the high and low speed compression and rebound adjustable shocks, making the final adjustments should be a piece of cake.

Adding a six point subframe to your YFZ requires that you weld two additional mounts near the bottom of the frame behind the engine. With the additional support from the lower mounts and the extra strength offered by its tig welded chromoly construction, Lone Star’s subframe offers vastly superior strength at the expense of a few additional pounds. While adding the chrome finish drove up the price, the beauty of the finish will be well worth it to the pilot for whom standing out is as important as performance.

With the gusseting and welding on the subframe mounts complete, it was time to add a new finish to our beefed-up chassis. To apply the new finish to our frame we turned no farther than Precision Powder Works, located on the same property as Earlywine’s Indoor Motocross and Earlywine’s ATV and Cycle. One stop shopping couldn’t get much easier for us. We wanted to go with a neutral color that would lend itself to any future color scheme, so we settled on an Extreme Chrome powder coat, with a clear coat overlay. The Extreme Chrome color will yellow over time so it is necessary to clear coat it to maintain its good looks. With the clear coat in place the finish is more metallic than the YFZ’s stock grey color and is an almost perfect match for aluminum components such as grab bars or handlebars.

More Chassis Goodies

Our Pro-Am YFZ could cut a reasonably tight line. However, the machine was most at home railing with the power on. Whether you were on an inside or outside line, the +2 ¾ inch long travel A-arms and Lone Star Axcaliber axle made our YFZ rock-steady-stable.

The only bad news in this article is the demise of a high quality chassis component manufacturer, Metal Craft Racing, who supplied us with extremely trick chromoly long travel A-arms and swingarm, have decided to hang it up in the ATV business to pursue manufacturing Rhino hop up parts. Since we started with Lone Star parts on the frame, if we were doing the project again, we would have just stuck with the proven Lone Star components for the rest of our chassis needs, however, with the Metal Craft parts in hand and our shocks already built, we decided to continue on.

In order to allow our suspension builder the ability the make the most of the wheel travel on hand, we went with +2 ¾ inch long travel A-arms up front with a standard length Metal Craft 4130 chromoly round housing swingarm in the rear. While many pros are starting to run light weight stock swingarms, not everyone carries around replacement parts and fewer change them before a failure occurs, so we were willing to run a bit more weight to help prevent an undesirable DNF. Taking care of the axle housing duties in the swingarm was a Lone Star Axle carrier.

To widen the rear of our machine, we installed a Lone Star Axcaliber Racing axle. The four inch overall wider axle spaced the rear out with the front and added considerable strength to the rear of the machine. Of course, if you have any issues, Lone Star’s Axcaliber axle is covered under an unconditional lifetime warranty against bending or breaking.

Shock Absorption

In order to make our machine competitive, we knew there would be no cutting corners when it came to choosing suspension. Elka Suspension has played a big part in the progression of technology in the ATV market. In 2002 they were the first ATV shock manufacturer to introduce high and low speed compression damping on their Pro Elite Series shocks. By splitting out the high and low speed compression damping, the rider has the ability to fine tune his suspension for smaller quick impacts and large hits separately. While this can be overwhelming for beginners, it opens up another level of tune-ability for riders familiar with tuning their suspension settings.

For a Pro Am level machine, we felt the rider should have as much adjustment available at his disposal as possible, so we ordered a set of 18 ¾ inch Elka Elite Series shocks for the front and an 18.1 inch shock for the rear. Both shocks feature 33 way high and low speed compression adjustment and 60 way rebound adjustment. Outfitted with the new suspension package our YFZ now delivers a whopping 10.5 inches of suspension travel up front and 12.5 inches in the rear.

To achieve such long rear wheel travel numbers, Elka set up our machine with their rear linkage. Elka’s linkages are made of CNC machined aluminum and are designed to increase wheel travel and provide smooth progressive rear suspension action. All the while they also allow the machine to set lower.

The final and equally important part of our suspension package is a steering stabilizer. As the shocks protect the rider and machine from vertical impacts on the track, the steering stabilizer is essential in preventing fatiguing horizontal impacts from reaching the handlebars. When we went shopping for a stabilizer, we were equally interested in durability and adjustability. 9 of the top 10 Pro class finishers at the Big Buck  GNCC in South Carolina finished with Precision Racing Product’s Stabilizer. If this stabilizer can hold up to top-level cross country abuse it should work great for our project.

Elka Elite Series shocks with an Elka Linkage out back deliver 10.5 inches of front wheel travel and a whopping 12.5 inches out back. Streamline steel braided brake lines and extreme duty pads front and rear were installed for better braking.

Precision has a history in producing extremely hi-tech components for military use. So building a steering stabilizer for an ATV should be a piece of cake. Company owner George Athanasiou tells us, “I remember Mike Hallock told us that he was hearing complaints from pro racers that there wasn’t a good enough steering stabilizer on the market, so we spent over nine months and over 30 revisions developing our steering stabilizer and now the number of top pros running it speaks for our results.”

We were intrigued by the stabilizer’s unique design plus its incredible range of adjustability. This is one of a few units that we are aware of that gives the rider the ability to stiffen or soften the damping in specific areas of the unit’s range of motion. If you are on an extremely rough track with lots of braking and acceleration bumps, you can tune the stabilizer for more damping in the middle third of the stabilizers range of motion, the position it would be in while hammering down a straight. At the same time, you can make the range of motion at each side of center as stiff or soft as you like for different damping characteristics in the corners. This extreme adjustability allows for more precise setup for different track conditions and makes things less fatiguing for the rider by allowing you to lighten the units damping for parts of the track where heavier damping isn’t necessary.

Pro Am Power

When it came to finding a motor builder, we wanted to look outside the box of five or so engine builders most commonly used on the GNC circuit and search for some new not-so-famous talent. On a tip from ATV Scene test rider Brit Mansell, we contacted SS Motorsports out of Hueypown, Alabama. We spoke at length with SS owner Scott Salter about our hopes and ambitions for our YFZ and Scott was confident they could deliver.

If you want to win in the Pro Am class your machine is going to have to be competitive in every way possible, and now days that includes the motor even though in stock form it performs well. As with the rest of the machine, we wanted a motor that was capable of running a pro race, while trying to maintain some reliability. We wanted them to wring out all of the power possible without the use of a higher rev CDI box, in order to keep from building a machine that would soon be revved into shrapnel.

We mailed our entire 2005 YFZ450 engine off to SS and they immediately got to work tearing the motor apart. To start, SS inspects all of the engine’s stock parts and any items showing wear must be replaced in order for SS to proceed with the engine build.  Scott explained, “No matter how good a motor builder is, a motor producing more horsepower will put more stress on almost all of its moving parts, that’s why we make sure no worn parts go back into a motor we build. We are especially concerned about parts in the lower end such as transmission components.”

At the heart of the transformation in our motor is a Falicon 1.45mm stroker crank. The Falicon crank brings our ’05 YFZ motor displacement up from 439cc to 450cc. The mild stroke increases horsepower minutely across the board but is most noticeable in the bottom end of the RPM range. Aside from the mild gains in performance, the crank is blue printed and balanced, helping minimize vibration and increasing reliability. Owners of ‘06 YFZs don’t need to stroke their cranks, however SS recommends having your stock crank modified with balancing and a new knife rod to work with their specially cut pistons for riders looking to wring out every bit of available horsepower.

While we retained our YFZ’s stock rev limit for more reliability, SS Motorsport’s built us a 450cc class legal motor with the power characteristic of an open class machine. While it’s blindingly fast, SS created one of the smoothest fully-built race engines we’ve ridden to date. One extra we weren’t expecting was the wired-in attachments for the included Pro Design kill switch and start button.

Back up top, SS installs a specially cut 13.5:1 JE piston kit. The higher compression piston increases power throughout the RPM range and its lighter weight allows the motor to rev quicker. To flow more air, SS Motorsports installs a new exhaust cam and ports the cylinder head. Port work includes their National port and polish of the intake and exhaust ports, their three angle valve job and machining of the valve guides.

When it comes to the carburetor, SS pulls out all of the stops by performing some serious carb modifications. To start, they install a complete Power Now and Power Plus kit on either side of the carburetor. The Power Now components are designed to better regulate air flow at lower RPMs giving better throttle response below one quarter throttle. From there, SSM modifies the carb's accelerator pump for better fuel flow, installs new jets in order to get the jetting in the ball park before the consumer finishes dialing in the jetting in at home and replaces the carburetor’s hard to reach air screw, with an easy to access knob, allowing for fine tuning by hand.

From there SS Motor Sports turns their attention to reliability. Some YFZs have had top end issues due to a lack of oil reaching the bottom of the piston, resulting in the piston pin breaking, thus grenading the entire engine. To help prevent this extremely expensive problem, SS performs their Crankcase Oiling Mod. They do this by cutting a new oil journal which shoots oil from the lower crankcase to the bottom of the piston helping reduce wear on the lower part of the piston and piston pin.

Yamaha’s oil vent system routes the air that is vented up and into the air box. This, according to SS, has two negative effects, the first is that you are sending hot air back into the air box which effects jetting and engine performance, the second is that small amounts of oil are occasionally blown up into the air box contaminating the air filter. SS eliminates this mess by simply running a tube to the bottom of the engine, venting the hot air and any oil blow off onto the ground, rather than back into your air intake.

When SS reassembles the engine, they replace all of the engines gaskets, seals, o rings and timing chain for reliability. They also perform their wiring harness modification, where they clean up the machine’s wiring by eliminating all unnecessary plugs and wire in labeled plug ins for a kill switch and start button. This kit includes a Pro Design kill switch and start button with the price for the mod. This is an extra step we don’t see many other motor builders offering and this extra thoroughness left us impressed with SS Motorsports even before we had a chance to fire up the machine for the first time.

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