Richard Sims has a long history...
Richard Sims has a long history of building serious horsepower machines that have graced the pages of Sport Rider many times.
For those who may be serious long-time readers of SR
, the name Richard Sims surely rings a bell. Sims' handiwork has been featured numerous times over the years in this magazine, from some of the original UFO shootouts back in the '90s, to the middleweight UFO shootout we did back in April '01 ("600s Gone Wild"), to his custom-designed/fabricated supercharged Kawasaki ZRX1200 ("Blown Away", Feb '05). Sims has one of those engineering minds that loves to figure out an elegant solution to a problem-and luckily for us, one of his favorite problems to solve is how to generate more power and get that power to the ground in order to go quicker and faster than ever before.
This particular project began about eight months ago when Sims decided he wanted to build a bike of his own. "Every other bike I've built was owned by someone else," said the garrulous bike builder, "so this time I wanted to build something that I could keep, and ride on the street." After a seven-year stint working for Muzzys Performance in Oregon, Sims moved back down to Sacramento to start his own Sims Motorsports speed shop. "I got tired of seeing all these 'blinged out' 'Busas running around that were all show and no go," relates Sims, "and Hayabusa owners spend a lot more money than the other bike owners at my shop, so I knew a 'Busa was going to be the starting point for my own bike."
Sims has been in the motorcycle industry for many years, so he's forged many business relationships in the performance market. That experience and his engineering knowledge allowed him and his son Ryan to build one of the wildest-and yet nicely crafted-Suzuki Hayabusas we've ever thrown a leg over.
Inside The Beast
An example of just how stout the Suzuki's bottom end was engineered is that a large majority of heavily modified 'Busas still keep the stock crank and rods, and Sims' bike is no different. "That crank is strong enough to handle nearly anything," said Sims. "Only if you're going for crazy horsepower do you need to go with aftermarket rods, and even then it's more for insurance than anything else. The stock rods in the second gen 'Busa are well built; the rod bolts are big and strong, and they can handle the stress of big horsepower." The bearings and crankcases are just as stout, although when the engine is seriously modified for major power, the case halves can actually "shuffle" against one another from the forces of the rotating crankshaft. This is where APE's heavy duty case and cylinder studs come in-their beefier construction keeps the cases and cylinder/cylinder head assembly together and sealed tight.
Ultra-light carbon fiber BST...
Ultra-light carbon fiber BST wheels shod with Avon VP2 Sport tires put the power to the ground. Brock's Performance titanium full exhaust not only has good clearance for cornering, but lowering as well. Vortex sprockets and EK chain transfer power to the rear wheel.
Huge 86mm CP forged pistons (stock bore is 81mm!) reside in a Muzzys Performance billet big block cylinder assembly. Interestingly, in order to fit such oversize bores while maintaining enough material between them, the Muzzys cylinder block (machined from a solid block of aluminum) actually has the bores offset to the outside in relation to the rod journals; the outer bores (cylinders 1 and 4) are offset 1.5mm, and the inner bores (cylinders 2 & 3) are offset 1mm. The pistons' wrist pin boss underneath has been machined for clearance, and even though the loads are uneven due to the piston offset, the APE tool steel wrist pins are so strong-they are used in countless drag bikes pushing 700 horsepower, with no record of a broken wrist pin ever-that Sims is confident there won't be any issues. There's a lot of work involved, though; because the cylinders are now offset in relation to the combustion chambers, the valve pockets in each piston head need to be modified (Sims feels that the cylinder walls aren't close enough to the valves to cause any shrouding or other flow issues). Total displacement of the engine is 1510cc.
Instead of the old-style, time-consuming method of hand-porting the cylinder head, Sims turned to Competition CNC in Oakville, Connecticut, to modify his cylinder head ports using a five-axis CNC machine (a method seeing increasing use in production with the OEMs). Because the porting is done by a machine, every facet of porting along every square millimeter of the port wall can be precisely and consistently controlled (and modified, using three-dimensional CAD programs). A three-layer Cometic gasket maintains a positive seal between the head and cylinders; Sims kept compression ratio down to a conservative 13.5:1, "because I knew we'd be doing top speed runs, and I wanted to ensure there were no detonation issues, especially when you start using nitrous." Custom-spec Megacycle camshafts using APE adjustable cam sprockets push on Kibblewhite stainless steel valves of stock diameter, with APE valve springs and titanium retainers ensuring that everything stays together at high rpm.
The stock Hayabusa fuel injectors are used ("They've got more than enough capacity to handle the engine's needs without nitrous," said Sims), and the airbox and ram-air intake system are all stock as well. Spent gases are handled by an exquisite Brock's Performance CT Series titanium 4-into-2-into-1-into-2 Dual Full System that is not only designed for maximum ground clearance for cornering, but also lowering for dragracing.
An Öhlins FGRT 43mm inverted...
An Öhlins FGRT 43mm inverted fork handles suspension duties up front, with four-piston/radial-mount Beringer Aerotec calipers and 310mm stainless steel discs helping bleed off speed.
Sims also outfitted his 'Busa with ceramic bearings from World Wide Bearings (which we found significantly reduced rolling friction in wheels back in our May '05 test, "Hybrid Ceramic Bearings") in the front and rear wheels. A two-stage MTC lockup clutch with beefy Muzzys all-billet inner and outer clutch basket ensures that the massive power gets transferred with zero slippage loss, and a tool steel shift shaft from Brock's Performance keeps everything working smoothly when the air shifter (utilizing a unique design by Ryan and Richard Sims that bolts into the left side cases) is punched during dragstrip runs.
Sims wanted maximum suspension performance, and he didn't want to mess around with the stock components, so he turned to Dan Kyle at Kyle Racing for an Öhlins FGRT 43mm inverted fork and fully adjustable rear shock. A set of ultra-light BST carbon fiber wheels from Brock's Performance are shod with Avon VP2 Sport tires to add to the traction quotient. Keeping all the speed in check is a pair of Beringer four-piston/radial-mount Aerotec calipers and 310mm stainless steel discs.
The custom Kosman extended...
The custom Kosman extended swingarm utilizes an axle block with two holes. The rearmost hole allows a 64-plus-inch wheelbase for dragracing and speed runs, while the forward hole shortens the wheelbase to the back end of the stock measurement.
Exquisitely machined Sato...
Exquisitely machined Sato Racing rearsets keep the rider's feet where they should be. The Nitrous bottle resides inside the swingarm in front of the rear tire. Note the incredibly nice welds on the Brock's Performance titanium exhaust.
This shot shows the Kosman...
This shot shows the Kosman output shaft support that prevents the countershaft from getting pulled back under the stress of high horsepower, hard launch conditions. The air shifter setup was custom designed and built by Sims and his son Ryan.
This fail-safe switch on the...
This fail-safe switch on the throttle cam ensures that the nitrous cannot be activated unless the throttle is wide open.
Excellent vision and aerodynamics...
Excellent vision and aerodynamics from the Zero Gravity double bubble windscreen were nice to have at 213 mph. Brock's Performance triple clamp allows access and adjustment of the Öhlins fork tubes, while a Pit Bull rotary steering damper quells headshake.
The elegant fabrication of...
The elegant fabrication of the wet nitrous setup on the Sims bike is evident when you remove the airbox lid. It took Sims and his son Ryan about 30 hours to design and build this custom setup.
Kosman Specialities designed and fabricated the unique lengthened swingarm that features "dual-hole axle" blocks. This allows the usage of the same swingarm for both an extra-long 64-inch wheelbase for dragracing, and a shorter wheelbase that is close to back end of stock length for regular street and canyon work. Kosman also designed (and sells) the output shaft support that connects the countershaft and swingarm pivot boss in the frame, preventing the countershaft from deflecting under hard launches and big horsepower at the dragstrip.
Here you can see the dual...
Here you can see the dual battery setup that pumps 24 volts to the starter motor for easy starting, while maintaining 12 volts for the rest of the electrical system. Lee's Performance re-flashed the stock ECU to disable the speed limiter, increase the rev limiter, and retard the ignition when the nitrous is activated. Schnitz PNC-3000 nitrous controller and Bazzaz Z-Fi fuel computer handle their respective categories. The DME Race Chassis aluminum rear subframe weighs half of the stock unit.
When it comes to electronic (and even electric) trickery, the Sims 'Busa is packed to the gills. For example, because a heavily modded 'Busa engine can be difficult to turn over quickly enough to fire up, Ryan Sims designed and fabricated a unique dual-battery system that briefly pumps 24 volts to the starter motor while maintaining a normal 12 volts to the rest of the bike's electrical system. By running a standard-size battery along with a smaller additional one in series, the system can produce the necessary current for easy engine startup while still retaining the stock charging system without overloading.
An increasingly popular mod these days is "reflashing" the stock ECU. Various portions of modern sportbike ECU programming can be modified-the trick is cracking the access code. The increasing sophistication of computer hackers has resulted in some shops being able to gain access and change the programming on some stock ECUs. Lee's Performance is one such place, and they re-programmed Sims' stock ECU in three ways: the 184 mph speed limiter has been disabled, the rev limiter increased from 11,000 rpm to 12,000 rpm, and a special feature that retards the ignition 10 degrees when the nitrous system is activated.
Ah, the nitrous system. Sims decided on a "wet" nitrous system (one that injects both fuel and nitrous, versus a "dry" nitrous system that depends on the stock injectors to deliver the extra fuel) because he has a lot of experience designing and building them. "Dry nitrous systems are neat because they're cheap and easy to install," said Sims, "but I'm more comfortable with wet systems because I know that enough fuel is being delivered." Richard and Ryan spent about 30 hours designing the custom nitrous system on the 'Busa, with an intricate delivery system that fits inside the stock airbox without restricting airflow. The system uses a recirculating fuel setup to maintain a constant five pounds of pressure to the fuel solenoids. A Schnitz Racing PNC-3000 nitrous controller manages the numerous fuel and nitrous solenoids, and offers countless options for fuel and nitrous delivery; the nitrous bottle is mounted within the swingarm in front of the rear tire.
Handling the fuel tuning side of the electronics is a Bazzaz Z-Fi unit. A very versatile piggyback fuel tuning computer, the big difference between the Z-Fi and "closed-loop" fuel tuning units is that the Bazzaz is able to record data so that you can see what changes are being suggested (and hence, what changes you actually make) to the fuel maps, giving you a more accurate measurement of your bike's state of tune.
Unleashed...For The First Time
After 20 years of conducting...
After 20 years of conducting top secret research and development for all manner of Honda automobiles and motorcycles (as well as our top speed and acceleration testing), the Honda Proving Center of California will be shut down due to budget cuts. We'll miss the place.
In order to find out what Sims' 'Busa project could do in a safe environment, we ventured out to the controlled high-speed confines of the eight-mile oval at the Honda Proving Center of California. Not only would the oval allow us to safely run at top speed, but also one of the lanes is concrete, offering excellent traction for acceleration testing (our highly accurate Stalker radar acceleration setup would measure the quarter-mile time/speed).
213 mph on a warm-up run,...
213 mph on a warm-up run, with no nitrous and not even in sixth gear yet.
We decided to do top speed testing first, out of concerns that the heavy and powerful 'Busa would likely spin the tire on the rear rim during a hard launch and throw it out of balance-a major issue at 200-plus mph. After changing the gearing for an estimated 230 mph top speed, I ventured out for some warm-up runs to get acquainted with the Sims 'Busa. It should be noted that this would be the first time the bike would ever be ridden in anger; its only previous forays were some short shakedown street rides around Sims' shop, and a day spent at the Bazzaz Performance SuperFlow dyno dialing in the fuel maps.
Sims wanted me to give it a run through a few gears to make sure the air shifter was working properly; Ron Thibodeaux of Bazzaz Performance also wanted me to check kill times between each gear (the Z-Fi can alter ignition kill times in each gear for optimum shifting smoothness). So after a couple of warm-up runs shifting manually and a quick stop to check everything out, I took off with my left thumb poised on the horn button.
The first two shifts went fine; but when I hit the horn button for the third-to-fourth upshift, nothing happened. Sims thought he traced the issue to inadequate clearance between the shift shaft arm and the air cylinder bracket. A little down time to disassemble the air shift linkage, a little grinding with a Dremel wheel and reassembly, and I was back on my way.
Bazzaz Performance's Ron Thibodeaux...
Bazzaz Performance's Ron Thibodeaux (left) adjusts fuel mapping on the Z-Fi unit, while Ryan Sims waits to bolt it back up for another run.
Thibodeaux wanted to get some air/fuel readings, so I made sure to wick the throttle wide open. The bike lept forward ferociously as I pinned the throttle in first gear, and the first-to-second shift went smoothly. But as I stabbed the horn button for second-to-third...nothing. A few more fruitless attempts, and I quickly slowed and turned to head back.
As I was riding back, I noticed that I couldn't even shift manually with my foot; the bike was basically stuck in third gear. A concerned Sims carefully went through the whole air shifter system, and couldn't find anything wrong. He even did a short shakedown cruise to manually shift the bike to make sure it wasn't a problem with the transmission.
Another test run produced the same results-the first two shifts were fine, then nothing. Time was beginning to become an issue, so we decided to do our top speed runs without the air shifter. It wasn't until the end of the day that Sims discovered the culprit: because he was using nitrous to pressurize the air shifter cylinder, it was freezing up after a few shifts, preventing even manual shifting. It wouldn't take long for the cylinder to thaw, thus the reason why it seemed to work later.
The trick to getting a good speed run at the HPCC oval is getting a good drive off the "corner" onto the straight. At 60 mph, the oval's four corners are leisurely bends, but at 150 mph, they are corners taken at some real lean angles, requiring some skill to get that drive onto the straight. On my first run to get a feel for things, I got a decent drive onto the straight, and kept it pinned into almost 10,000 rpm in fifth gear before shutting down due to a persistent weave. As I cruised back to the pit, Sims and his crew were excitedly hugging each other; it turned out I went 213 mph...on my first warm-up run.
The windsock above our pit...
The windsock above our pit stall on the HPCC oval tells it all. High winds forced an end to our top speed testing before we could better the initial 213 mph run.
I figured there was easily more to come. Unfortunately, the desert winds started picking up by the afternoon, and even though I was getting better drives onto the straight and turning more rpm than before, I was unable to better that mark. The 25 mph sidewinds were causing enough aerodynamic resistance (in addition to instability) that the rear tire was spinning, which was why the rpm was higher but the speed was slower. In fact, on my last four tries, I could actually smell burning rubber as I hurtled along at 205-plus mph. Attempting to use nitrous would've only caused the tire to spin more (as well as possibly introduce more instability), so we held off using it.
We retreated back to set the bike up for dragstrip runs, but more problems conspired to shoot down those plans. Despite the bike's immense power, Sims didn't have short enough gearing for the quarter-mile; I was barely getting into fourth at the traps. The lack of air shifter made accomplishing the first upshift off the launch very difficult, and precluded any nitrous use; and then the clutch decided to give up the ghost after four runs. Not how we wanted to end the day-but we got an early taste of its potential.
I'll Be Back...
The Sims Motorsports crew...
The Sims Motorsports crew (left to right): Ryan Sims, Hayabusa.org's Kent Collins, Bazzaz Performance's Ron Thibodeaux, John Voter, and Richard Sims.
A close look at the studio shots of Sims' bike shows how much work went into its construction-this is definitely not some-thing hastily cobbled together. And anybike that can go 213 mph on a lazy warm-up run with no nitrous leaves us wanting more. So we'll be getting Sims to bring his bike back for another try in the near future. Stay tuned.