Mighty Micro Powerplants

image 1


How motorcycle engine builders find big power in small packages, keeping pace with some of their larger race vehicle counterparts.

Successful engine builders have always been the ones who are able to adapt and evolve. Whether it’s reacting to new rules, new technologies, or an entirely new discipline, change is the name of the game.

Arguably, nowhere is this evolution more pronounced than with motorcycle engine builders. For many of them, what started as a career in the two-wheel world was upended by the confluence of two opposing trends: the decline of American motorcycle road racing and concurrent rise of motorcycle engine classes invading the circle track scene.

“We started out as a motorcycle shop and worked on a lot of road race motorcycle engines up in the Northeast,” said Will O’Connor at NPS Racing, Ransomville, New York. But, due to changing rules and the American Motorcyclist Association’s (AMA) decreasing involvement in sanctioning road racing, his business “kind of fell off. So we were lucky when the small car market took off.”

Micro Mania

While motorcycle engines appear in various four-wheel applications, micro sprints have become a popular discipline for motorcycle engines. For example, this year’s Tulsa Shootout drew more than 1,600 entries across six different classes of micro sprints.

As for O’Connor, micro sprints weren’t his original destination. He learned his craft at the American Motorcycle Institute (AMI) in Daytona Beach, Florida, before moving back to New York, where he worked on and raced road bikes. Following the AMA’s lessening race involvement in the mid- to late 2000s, micro sprint engines became O’Connor’s main source of work. He estimates it’s now roughly 75% of his business.

“I always tell my wife, ‘I’d have been out of business a long time ago if micros hadn’t come along,’” said O’Connor. “My heart still lies in the road racing stuff because that’s what I wanted to do and road raced myself for a while, but the micros pay the bills. They keep the doors open.”

The micro sprint discipline has wide-ranging appeal, featuring smaller versions of full-size sprint cars powered by side-mounted 600cc motorcycle engines that run on methanol. It is a popular entry-level class for aspiring young racers, but experienced racers also enjoy running micros for the affordable, high-adrenaline action they provide.

image 2
Though he started NPS Racing building engines for road race motorcycles, Will O’Connor reported that engines for micro sprints now make up 75% of his business. “The micros pay the bills. They keep the doors open.”

“We have guys who stay in the micros for quite a while,” said O’Connor, “just because the performance versus cost is pretty good. It’s hard to beat.”

Affordability and performance can vary widely depending on the class and the region. Midwest-based micros run in the A-Class or in Outlaw class. While the A-Class is popular among the cost-conscious racers due to its stock engine requirement, the Outlaw class allows any engine modifications up to a maximum 636cc displacement motor. This can significantly increase both cost and performance.

However, most East Coast tracks play by a different set of rules, governed by the Universal 600cc Sprint Association (U6SA) Rules Committee. Engines are limited to 600cc, and builders aren’t allowed to do any porting or crank lightening.

“Most of the mods we’re doing are increasing compression, changing cams, cam timing, and building the bottom end of the engine so that it’s capable of handling the increased loads and extended high rpm from the cars,” O’Connor said. “There’s also a lot of power to be gained in the cylinder head by doing a good concentric multi-angle valve job that provides better valve sealing and better flow over the valve seat.”

Like most engine builders, O’Connor said he prefers to “build engines with the Outlaw rules. I can replace the OEM components with my own custom designed engine parts, resulting in a stronger platform that is unique to my shop and produce something not everyone else has the knowledge or capability to duplicate.”

Regardless of the rules, a winning race car still requires a solid powerplant. The debate about which reigns supreme in micros is constantly changing.

The Kawasaki 636 used to be the dominant engine in the class, but the manufacturer stopped making that engine in 2006. While it remained popular for some time, these engines began to wear down, and demand shifted to the Yamaha YZF-R6. O’Connor noted that the Suzuki GSX-R600 is now gaining popularity, as it has proven to be a more reliable powerplant.

“With the Suzuki, the components they use from the factory are pretty good,” he explained, though the engine may seem “a bit overbuilt versus the Yamahas,” which use “borderline the lightest components they can get away with to make the same power, but they don’t seem to hold up as well.”

Jon Fitzpatrick of FTZ Racing in Cape Girardeau, Missouri, focuses mostly on the Yamaha YZF-R6 and Suzuki GSX-R600 platforms, while also doing a few Kawasaki ZX-6 engines as a “budget option.” He explained that the Yamaha’s popularity stems from its rpm capabilities.
“With the introduction of the Yamaha R6, the rpm capabilities went from under 14,000 rpm to over 16,000 rpm,” explained Fitzpatrick. “With this came new challenges to keep them reliable, such as changes in the oiling systems and bearing clearances, and we introduced products like our FTZ oil cooler package.”

In addition to the oil cooler package, FTZ Racing made significant investments in its shop to develop and produce new products for the micro sprint market, especially in the Outlaw class.

“We have some advantages over many ‘engine only’ shops because we have a full machine and fab shop, along with our own in-house CNC equipment,” said Fitzpatrick. “If we want to change something up, like the dome shape of some pistons, then we just take them downstairs and do it. Plus, we make our own EFI systems and many billet engine accessories, as well as our FTZ exhausts in-house. It gives us full control of the entire horsepower package.”

It may sound like an operation for a dedicated full-fledged sprint car team, but FTZ Racing focuses exclusively on micro sprints. Just like all forms of racing, advanced technology is beginning to work its way into the micro sprint classes.

“The latest game changer is the electronic fuel injection,” continued Fitzpatrick. “The ECU we use for our EFI has totally accessible tuning of all aspects and is complete with integral data acquisition. This takes out much of the guesswork about tuning like we all had to do back in the day. It is a real advantage for those teams that are willing to embrace the technology.”

Despite the new tech, there are still some core foundational principles to follow. Builders we spoke with had sage advice for racers looking for a motor: Don’t risk a salvage one.

“I tell my customers that you have to start with a strong foundation,” said O’Connor. “I always like to see guys purchase a completely built engine from us. Otherwise, the majority of these engines come from crashed sport bikes, and if they were laying on their side running without oil pressure for even a few seconds, they could have oil-starved a bearing. It can go right away, or it can go a couple races and then spit a rod out, but it’s pretty catastrophic at that point.”

Also considering that these engines are being used in cars instead of motorcycles, one of the most important modifications is the oil pan and pickup.

“I have seen a lot of pans designed that had good intentions but failed because either the pickup wasn’t designed correctly or the pan angle and oil sump volume weren’t correct,” said O’Connor. “The cars tend to push the oil to one side or a certain spot in the oil pan, and if the pickup isn’t in the correct location, it will starve for oil at some point during the race.”

Additionally, he noted that due to the extreme stress these engines experience during the race, “Keeping oil pressure and temperature in check is crucial to minimizing engine failures.”

Prototype Powerhouse

On the other side of the country, a fellow AMI alum charted a similar path from the world of two wheels to four.

George Dean of George Dean Racing in Mountlake Terrace, Washington, worked exclusively on bikes during the 1980s, until a customer asked him to build a motorcycle engine—a Kawasaki GPz550—for his daughter’s dirt car in 1989.

image 3
Powered by side-mounted 600cc motorcycle engines, micro sprints provide an affordable entry point for aspiring racers while also appealing to more experienced competitors. This year’s Tulsa Shootout drew more than 1,600 entries across six different classes of micro sprints.

“I thought I had a fish on the line there,” recalled Dean. “Whoever heard of putting a bike engine in a car?”

Luckily for Dean, he followed through with the customer’s request and helped them test the car at Deming Speedway in Everson, Washington. During her first race with Dean’s new engine, 15-year-old Shawna Wilskey drove from last to first and won the race.

“That’s when this lightbulb went on inside my head,” said Dean. “I thought to myself, ‘I’ve got something here.’”

Local dirt racers started bringing him engines, but eventually word of Dean’s success trickled into the local road racing club. In 1990, Dean built a 1,000cc Kawasaki ZX-10 for a road racing car and success followed. He continued working on both cars and bikes throughout the ’90s, and then in 2004 shifted to exclusively working on race engines—primarily in the road race scene—where competitors spare no expense building prototype cars.

“The road racing thing is so much different than the dirt track thing,” said Dean. “With dirt track, you can go racing for a fairly reasonable amount of money. The road race cars I play with, the Prototype 1 (P1) and Prototype 2 (P2) class in SCCA, it’s very common for a guy to invest $150,000 to $200,000 in their race car. And this is for a hobby, guys going out and racing for a wood plaque and a flag.”

Dean has made a name for himself in the Sports Car Club of America (SCCA). By his count, cars with his engines have tallied up 15 SCCA National Championships, including a recent major achievement for Dean. “When we were in Indianapolis (for the SCCA National Championship) a couple of years ago, we were the fastest car in the whole event, and there’s 700 competitors out there, throughout all these classes of cars. We beat up on all those automotive-based cars. That was probably one of my crown jewels.”

According to Dean, his success starts with understanding and protecting against the extra stress these engines experience in a car versus a motorcycle.

“When we’re putting these motorcycle engines into these race cars, we’re making those engines do things that they were never designed to do,” said Dean. “G-forces are fighting the internal parts of these engines, and the main thing is keeping the oil where it belongs. At 2G, that’s like taking the engine and laying it on its side while it’s running at 12,000 rpm. You start sucking air into where the oil is supposed to be going, and at that speed, it doesn’t take hardly any time at all to damage the bearings and for the engine to fail.”

image 4
George Dean has found success building motorcycle engines for dirt track racers as well as road race customers. His approach to engine building is focused on longevity. “I decided I was going to emphasize making the engine as strong as I possibly could to keep the reliability there.”

With that in mind, Dean leans into the “to finish first, first you must finish” approach that prioritizes engine longevity. “I decided I was going to emphasize making the engine as strong as I possibly could to keep the reliability there. We kept refining the oil systems to make them better, and the engines became more reliable.”

Right now, the Kawasaki ZX-10R is Dean’s “weapon of choice,” producing 210 horsepower straight out of the box. In the SCCA Prototype 1 class, where the only limitation is a naturally aspirated engine capped at 1005cc, he’s been able to increase those numbers to “225 to 228 hp fairly easily.”

He said it’s “all basic stuff—add compression, cylinder head porting, camshafts, and for strength I put Carrillo connecting rods inside the engine, and that’s about it. There’s not a lot of super black magic science that goes on here.”

Pushing 230 hp in a 1,000-pound car, Prototype 1 vehicles are fast and on edge. However, Dean has seen the rise of automotive-based engines in this class, which feature more power but also more weight.

“Unless something drastic happens, I have a feeling we’re in the twilight of the motorcycle engine classes in the road race cars,” said Dean. “The automotive cars are definitely taking over; I think the cars are more comfortable to drive, and the popularity is there.”

Dean has adapted to this latest shift by going back to his dirt roots, which now make up about 50% of his business.

“A few years ago, a guy called me and said, ‘I want you to build an engine. We’re going to go win Clay Cup [at Deming Speedway],” said Dean. “I just had this feeling that I had unfinished business up at that track. I hadn’t been there [in 15 years], but we had a good driver, a good car, and we won that first year. As a matter of fact, we won three in a row.”

The disciplines may change, but Dean’s dedication to extracting reliability and performance from motorcycle engines has always kept him at the front of the pack. “There’s been a lot of (engine builders) that have come and gone, but I’ve hung in there and just continued doing it, day-in and day-out.”

A Legion of Legends

It’s been more than 30 years since US Legend Cars International (USLCI) in Harrisburg, North Carolina, first hit the racing scene. These spec cars have become hugely popular among developing young drivers and hobbyists alike. However, a new sealed powerplant has reduced opportunities for engine builders.

These 5/8-scale fiberglass silhouettes of classic modified American race cars were traditionally powered by Yamaha FJ1200/XJ1250 engines. But once Yamaha took that engine out of production after 2014, USLCI introduced the 125-hp Yamaha FZ-09 sealed engine in 2018, while the MT-09 is the new generation of this motor.

“The reason US Legend Cars International went with the Yamaha FZ/MT-09 is because it was an excellent platform for the Legend Car, and Yamaha was discontinuing their XJ1250 air-cooled carbureted engine that we had run for 25 years,” said Graham Smith at USLCI. “With the change, we were able to source an ECU that only USLCI can control. We couldn’t ask for a better platform to use on our cars, and the results show on the track with increased longevity, ease of use, and overall customer satisfaction.”

The 847cc liquid-cooled inline-three motor has helped level the playing field from a powerplant standpoint, but not everyone is happy about the new sealed motor.

“They’ve 100% sealed those engines, so nobody can work on them at all,” said Randy Raduechel of Raduechel Performance Motorsports, Oakdale, California. “We’re on the West Coast, and we can’t even adjust the valves on those things. That engine has cost us a lot of business because at the height of it, I was building 50 engines a year with the FJ1200. I haven’t built a FJ1200 for a Legend Car in three years. I build them more for street bike guys now.”

The sealed engine is reliable, but if it needs any work, it needs to be sent to USLCI headquarters in North Carolina for a tune-up or repair.
“It’s a water-cooled engine that just runs forever,” said Raduechel. “Guys are getting a season out of them, and then they send it back for a freshen up. (USLCI) takes it apart, grinds the valves, puts a set of rings in it, and then they run it for another year.”

image 5
In 2018, US Legend Cars International started using Yamaha FZ-09 engines, and recently debuted the upgraded MT-09 platform. “With the change, we were able to source an ECU that only USLCI can control” said Graham Smith.

In California, Raduechel has seen car counts fall, which he believes is due to the new sealed engine. “If you force me to send my (engine) across the country to have the valves adjusted, people aren’t going to invest in that. They’re seeing a heyday back East, but it’s killed the series out here.”

On the East Coast, renowned engine builder Hank Scott of Real Race Cars Performance Engines in Concord, North Carolina, has been building Legend Car engines for 25 years. While the new sealed motor is off-limits, Scott is now the “sole sealed engine builder for the XJR1250 for the past two years.”

The XJR1250 has no shortage of power, with Scott able to see horsepower numbers in the “upper 150s” to go along with “above 106-foot pounds of torque.” Strip away the rules and he’s been able to push this engine to ridiculous numbers.

“We have built this same engine for other applications making 133-foot pounds of torque and over 230 hp,” said Scott. “We concentrate on our valve work and bore finish, to make sure the engine is sealed up—in that area gains are noticeable. Of course, we know what valve lash, cam timing, and ignition timing the engine likes, all of that is a total combination to arrive at those numbers.”

Unfortunately, too much power can be troublesome in the Legend Car class. With many struggling to transfer all that power to the ground, they often opt for the three-cylinder FZ/MT-09.

“The FZ/MT-09 is much easier to drive,” said Scott. “They have 18- to 20-foot pounds less torque, so they don’t blow the tires off like the 1250 does.”

With the right driver and setup, Scott believes the XJR1250 still has the advantage on ovals “due to its enormous torque over the three cylinder.” As for how things look going forward, he believes the “1250 is still popular,” and expects racers to continue using both powerplants. It simply “depends on the driver and what they like.”

The new sealed motor hasn’t worked out for everyone, but as both builders noted, Yamaha’s discontinuation of the XJR1250 forced USLCI’s hand into making the switch. It’s part of an ongoing trend that has added yet another challenge for these builders.

“A difficult part is the motorcycle industry itself is changing,” said Raduechel. “They’re not producing (engines) in such long cycles of life.”

New series, new rules, new engines, new disciplines. In the motorcycle engine classes, it may seem like the only constant is the need for constant adaptation. Nevertheless, builders continue to meet the challenges of these mighty but micro powerplants.


FTZ Racing
George Dean Racing
NPS Racing
Raduechel Performance Motorsports
Real Race Cars Performance Engines
US Legend Cars International


Stay Connected

Sign Up For The PRI eNewsletter to get the latest in racing industry news, special events, new product information and more directly to your inbox.