A Custom Yamaha Royal Star With The Heart Of A V-Max

Nicknamed Neutron Star, this celestial Royal Star beats with the heart of a V-Max

Custom Yamaha Royal Star
Wonder what it would be like to have a V-Max motor dropped into a Royal Star frame? Here's your answer.Kevin Wing

This article was originally published in the August 2001 issue of Motorcycle Cruiser.

Once in awhile we come across a custom metric cruiser that really counts. A custom with a purpose, or in the case of National Cycle's Neutron Star, two purposes, which have been meshed perfectly into one reality. I think we can all agree Yamaha's luxuriously styled and well-adorned Royal Star is a good-looking motorcycle right out of the box. And for many, it has only one drawback—a V-4 motor with the dimensions of a rottweiller, and the bite of a beagle. As Barry Willey, president of National Cycle, says, "It was well-known that when this bike came out it had a V-Max engine in it, and that created anticipation for what it would be like. But they de-tuned the power."

National Cycle, the world's oldest windshield and aftermarket accessory manufacturer, has been collecting stock motorcycles for decades. "We buy significant bikes," says Willey, "like the CB750, Z1B, Valkyrie, V-Max…and when the Royal Star came out we had to have one of those too." National Cycle uses those bikes as templates for development and later retires them to a stable of mounts used for pleasure riding by enthusiasts at the company. However, National only started building its own customs a few years back, beginning with a 1947 Knucklehead customized exactly like a bike pictured in the company's 1948 catalog. "We put on a windshield and light bar from that era…leather saddlebags, seat skirt fenders, tail gunner lights, bullet lights and so on. We made all that kind of stuff in those days," he explains.

Custom Yamaha Royal Star
The bike looks like a Royal Star, but has been enhanced enough to immediately appear unique.Kevin Wing

So one evening last year, Willey and some of his cohorts (including his enthusiastic wife, Ann, and faithful product specialist, Bill Crawford) were sitting around during what he affectionately calls Miller Time, discussing their favorite topic—motorcycles. “That Royal Star is a great bike…it’s beautiful, has a wonderful seating position and steers real nice, but…huh…. Wonder what it would be like if we dropped a V-Max motor in there…?”

Some ideas hit you like V-boost. You’re moseying along and all of a sudden you’re thrust into a new dimension. Before long the Miller Time curiosity turned into an investigation. What would it take?

“Our research gave all the appearances that the engine would fit right into the chassis,” says Crawford, who headed up development. “We figured since that would be the biggest hurdle we’d go ahead with the project.” As fans of this Neutron Star, we are certainly thankful those preconceptions about the process were optimistic, otherwise the project may never have gotten off the ground. The team soon realized the heart transplant sounded a lot easier than it turned out to be.

“We were right, in fact, that the engine did line up with the motor mounts and it fit into the frame…until we went to put the carburetors on it,” says Crawford. “That required that the frame be modified rather extensively to give enough room for the carburetors to sit up out of the motor. There are considerable differences from the cylinder heads up between the Royal Star and the V-Max.

Custom Yamaha Royal Star
The idea to fit a V-Max motor into the Royal Star spawned out of a discussion Barry Willey was having with his wife Ann and product specialist Bill Crawford.Kevin Wing

“Once we got the chassis modifications made so that the carburetors would fit, the next step was to modify the interior tunnel on the gas tank to fit around the changes in the chassis…then we had to enlarge the tank so it would still hold some fuel.” This required widening the tank considerably. It actually took two stock Royal Star tanks to come up with the one you see here. Once the motor was situated, the National Cycle team had to deal with the exhaust. Neither stock situation, nor any existing aftermarket application came close to working.

“The angle of the exhaust ports coming off the cylinder heads on the Royal Star are different than on the V-Max,” says Crawford, who, with advice from world famous racing exhaust system builder Arrow, and fabrication assistance from vintage Indian restorer, John Dohnal, created a completely new system from scratch. “On the V-Max [the pipes] go straight out and under the radiator and then snake through the frame in the back. There were no such provisions on the Royal Star.” The Royal Star radiator is also larger and sits lower, so the new headers had to take a hard right to get outside the frame rails before they could run back, collect and be channeled into the muffler (a Borla unit built for Harley’s Road King). “This isn’t something you try at home,” laughs Crawford. “But it looks good and works surprisingly well.”

Custom Yamaha Royal Star
Although the Neutron Star was not supposed to be a show bike, there are many trick accessories from National Cycle to make it a unique everyday ride.Kevin Wing

Willey says he thinks they owe a lot of the horsepower increase to the exhaust, “but the carburetion is what really makes this thing honk.” Dialing-in the motor was a task taken very seriously and most of the tuning was performed in a local dynamometer bay. The team also disabled the V-boost by removing the butterflies to get a nice, flat acceleration curve. “We all love the fabled boost, but it is really just an imperceptible dip in horsepower. When the butterflies open full again it creates the sensation of a slingshot. It’s just nice, smooth, heavy power now,” says Willey, “and better ridability.”

The bike really is fantastic to ride. I rode to Daytona on Honda’s new VTX 1800 and grew accustomed to useable power. When I jumped on the National Cycle Neutron Star, however, I was in for something more. It was a gas—the only cruiser I’ve ridden lately that puts the VTX to shame, and with a nice, deep growl to match its grunt.

But getting to the finished product wasn't a piece of production-bike cake. This was a blending of two quite different stock bikes followed by a delicate application of thoughtfully chosen components that accentuate the performance aspects of the bike, without taking away from the luxury and tourability. Not to mention it was a costly venture (start with the price of two stock bikes instead of only one). "It was an evolving thing," says Willey. "We knew what we wanted to do with the engine and knew we wanted to go with an upside-down fork. We wanted to use available elements of performance—what you might find on a sportbike—and blend them with the cruiser. This was not supposed to be a show bike. We wanted it to be an everyday riding bike, so we defaulted toward function, rather than really wild things like stretching the tank." And ride it they do. The Willeys ride the thing like it's a touring bike and get attention everywhere they go. "The performance level is just about perfect," he says. "We had so much fun at Daytona. Ann didn't want any Harleys to pass [us]. We had a lot of fun blowing these guys off with their big S&S engines. They didn't expect it from a Royal Star-looking bike."

Custom Yamaha Royal Star
"People look at this bike and want to know if they can do it," says Willey. "It's not something an amateur is going to do under the shady tree in his backyard, but with some help from a shop it's quite doable."Kurt Lauer, PC Studio

The bike does look like a Royal Star, yet it has been enhanced enough to immediately appear unique, even without the telltale black motor, which they wanted to keep as stock-looking as possible.

“People look at this bike and want to know if they can do it,” says Willey. “It’s not something an amateur is going to do under the shady tree in his backyard, but with some help from a shop it’s quite doable.” That is, of course, because National Cycle already has worked out the biggest bugs.

One of the main headaches was incorporating the ignition control unit (ICU) from the V-Max into the Royal Star wiring harness. "There isn't enough information in the manuals to tell you what the wiring is doing," says Crawford. "Even talking with the techs at Yamaha didn't help much since the bike was so modified. A lot of it was stumbling on the right answers.

“The Royal Star uses four pickup coils in the igniter and the V-Max uses one that is timed through the ICU. It went through all kinds of permutations,” he says. “Getting the Royal Star speedo to work again was also challenging since it’s grounded through the more complex stock ICU. We finally found the appropriate wire, tied it to ground and suddenly everything worked fine. After losing lots of hair, finding such an easy solution was almost embarrassing.”

Custom Yamaha Royal Star
The V-Max motor sounded a lot easier than it turned out to be, but the engine ended up lining up with the mounts, it just needed some frame modification to fit the carbs.Kevin Wing

The Neutron Star's rear wheel is from the stock V-Max (the front is from Performance Machine), as is the rear brake caliper, although it's custom mounted. National Cycle also changed the pinion gear in the Royal Star differential so it had the same aggressive V-Max gearing. There are many trick accessories on this hybrid Yamaha— many which come right off the shelf at National Cycle. (For a full accounting, see The Recipe below.) One-offs include the saddlebag/turn signal combination, which Crawford designed. Another of his favorite touches is the clean placement of the license plate. "Basically I just bought a regular plate frame and chrome backing out of one of the Harley aftermarket catalogs, then I located bolts to fit it which have little lights incorporated right into the heads." He brought the plate up from the fender using a bracket made for a Sportster.

The Neutron Star name and complementary paint job were final touches. “Yamaha is using this Star name for its motorcycle and none of them have much impact in my opinion,” says Willey. “Royal sounds OK…like a nice, comfy motorcycle. Neutron Star represents immense power—cataclysmic power—and I thought that would be an interesting moniker to throw onto something that can really get up and go.” The paint was applied by Alcalde Customs, including the Neutron Star depiction on the tank, which was generated from an actual Hubble Space Telescope outtake.

Many people who see this bike wish that Yamaha would take the hint and produce a high-performance version of the Royal Star. If you like what you see, please let us know and we’ll pass it on. Meanwhile, Barry, Ann and Bill will be having all the fun, riding the world’s first Royal Star/V-Max cross. Finally, a Star with more bite than its bark.

Custom Yamaha Royal Star
National Cycle's Holdster Windshield Bags can secure gloves, glasses and other goodies within reach. There is a single pouch and this triple pocket option.Kevin Wing
The Recipe:
Suspension, front: GCB #54RWL, all chrome, with TiN sliders
Handlebar: Yamaha #STR-4WM75-13-00
Risers: CCI #19-270 (one-inch rise)
Riser bolts: CCI #32-771
Handlebar damper kit: CCI #42-901
Wheel, front: Performance Machine Trespasser
Brake, front: Performance Machine six-piston calipers
rotors: Trespasser
Front brake master cylinder: Performance Machine
Brake hoses: Russell Stainless
Clutch master cylinder: Performance Machine
Wheel, rear: V-Max
Brake, rear: V-Max
Switch housings: Modified stock (chrome plated)
Mirrors: Kruzer Mirrors, Biker’s Choice #49-9697 and #49-6998
Exhaust headers: Custom-made
Mufflers: Borla Road King slip-ons
Air filters: Uni-filter individual
Fender, rear: Royal Star
Fender, front: Road Star
Front fender tip: Yamaha #STR-4WM26-90-00
Seat: Corbin for Royal Star
Backrest assembly: Yamaha
Fuel tank: Royal Star, modified
Headlight: Excelsior-Henderson Super X
Headlight mounting block: CCI #05-769
Taillight and rear turn signals: CCI #65-307
License bracket: Sportster, modified
License frame: CCI #46-056 with lights
Spotlight bar: Yamaha Royal Star, modified, with teardrop lamps and National Cycle turn signals
Tachometer: CCI #27-821
Tachometer bracket: CCI #09-039
Floorboards: Jardine California
Engine guards: Yamaha
Jetting: Dynojet
Custom paint: Alcalde Customs
Dyno tuning: DGY Motorsports
Windshield: National Cycle N2210LW
Windshield outside trim: National Cycle N740
Windshield chrome inside: National Cycle kit-CHP (verticals); kit-CHS (horizontal)
Windshield bag: National Cycle N1310
Windshield mounting kit: National Cycle kit-CTA
Windshield chrome lowers: National Cycle N762
Saddlebags: Cruiseliner Bags #N1101 modified with turn signals
Saddlebag mounts: Custom-made
Spotlight switch: Custom-made