Monster, normally aspirated power on pump gas! By the staff of Dirt Wheels

Once you see R&D maestro Joey Strub behind the wheel of the Stage 4 RZR Pro R, you start to understand his constant search for power for the Pro R. He can use it all.

There are a few proven ways to build a stunningly fast UTV. You can make a huge quantity of horsepower, or you can build a very light machine with more modest power. Performance comes down to power per pound. More power and less weight are the goal. Like anything else, you can push that line too far and make a machine that is fast, but is also a handful or not even fun to drive normally. You must make sure to understand the job when you start building the tool.

There are a lot of performance companies out there in UTV land. We had only recently heard of Bikeman Performance. We tried to get together at Sand Hollow State Park in Hurricane, Utah, at the UTV Takeover. We saw them and their quiver of machines, but mostly going the other direction at high rates of speed. We never got it together.

We ran by the rig at Camp RZR, but again, the place was deserted. These guys like to drive! We realize they are out getting the cars in front of more eyes, but it is still fun to see a crew so engaged in participating. When we ran by the rig again, the crew was there by default. They were out of fuel! Or, fortunately for us, almost out of fuel.

There was some discussion of “running into town” for more gasoline. That puzzled us. None of the local towns had race fuel that we knew of, and surely a 330-horsepower Polaris RZR Pro R must swill straight race fuel, right? Nope. Premium out of the pump. That was the first surprise. Then we started looking for forced induction. Much of the rear of the car was skeletonized to make service easier and to drop weight. Even without all the bodywork or bed floor in the way, we couldn’t ferret out a turbocharger or supercharger. It was the same result scouring for a nitrous-oxide bottle.


Bikeman Performance (BMP) claims to take great powersports machines and make them better. Like a lot of companies, BMP’s newest design challenge was the Polaris RZR Pro R. Joey Strub, head of R&D at BMP, says, “The Pro R engine is the four-cylinder we have been waiting for. It is a strong and reliable platform to be able to pump in horsepower and have it stay reliable.”

You may ask, how do you make a 225-horsepower UTV that has tons of power and performance even better? More power, of course! Bikeman has several ways to get much more power than the stock 225 horsepower. You can chip away at the numbers, adding one level at a time or just go all out with a Stage 4 Performer kit. The eternal question: How fast do you want to spend? Some stages of Bikeman’s power plan for the Polaris Pro R are surprisingly affordable, but Stage 4 is a commitment.

BMP’s UTV products fall under four areas of performance: clutching, tuning, exhaust and internal engine modifications.

What a monster this machine is. It scoots when you hit the throttle, and any rise is an excuse to get the front tires in the air. It is that fast, and that fast is thrilling, and for some it is fun.


BMP’s SNYPR weights fine-tune power delivery. BMP optimizes the angle of the weight, and how heavy and where the weight is located in the clutch weight. The weights each have two bores lengthwise that accept various-length set screws. In addition to the differing weight of the different set screws, they can be threaded deeper or shallower to affect engagement rpm. The weights have locations that accept small magnets to further adjust the weight positioning. The SNYPR has countless different weight positions to fine-tune your driving style. 

Belt tension is adjusted via the spring. BMP’s final adjustment to clutching is cooling. The crew admitted that getting clutch temps lower was hard until it came up with the Cyclone clutch cover. They claim the cover reduces belt temps up to 30 degrees, giving longer belt life with better transfer of power with a stiffer belt.

Bikeman has deleted the excess bodywork in the cargo bed area. It gives a better look at the monster engine. As you can see, there is no forced induction hiding in there anywhere.
Of all the Bikeman Performance parts, this is the one we’d like to see upgraded. It was loud for our tastes. Where we ride it would attract too much attention.


This is where the Pro R comes to life and where Bikeman has big gains in the Pro R engine. With cams and a torque link ECU tune to optimize fuel and air, BMP can add up to 100 horsepower to this engine while still being on pump gas. For race applications, BMP can go to 50, 55, 65, all the way up to 75 horsepower using bolt-on parts with correct fuel octane.

According to BMP, the engine block can take a lot of pressure from the increased fuel and air, which allows them to really dial up the performance. Exhaust is the final part to the puzzle. Exhausts do more than just expelling burnt fuel gases. 

BMP has spent years developing snowmobile exhaust systems. It is able to manipulate the flow, and create the power and sound harmonics its customers love.

We approve of the light and bright wrap that gets away from the dark stock colors. This is a good-looking, very purposeful car. It is made to embarrass other cars in a drag race.
Look how hard 330 horsepower wrinkles the sidewall on those Blackbird Pro paddle tires. The tires and the power launch this car extremely hard. It just keeps accelerating.


Naturally, you can start with a flashed ECU or an exhaust, but the Pro R Stage 1 bolt-on Performer kit is a great start at $1,749.95. It includes the slip-on muffler, torque link ECU tune, Cyclone clutch cover, and Pro R double-barrel SNYPR clutch weight and spring set. Just those few changes bump the power near to 270 at the wheels! Stage 2 is the same kit with a different clutch helix for about $100 more.

With the $2,749.95 Pro R Stage 3 bolt-on performer kit you are still not making internal engine changes except dropping in the BMP-exclusive Brian Crower cams with the stock valve train. Aside from the cams, the Stage 3 kit is the same as Stage 2. Horsepower is approximately 300 with the Stage 3 kit. Impressive numbers for a kit designed to be installed at home by the owner.

Bikeman has a video on their website that shows how to drop the cams in. It claims the job takes about three hours, and any reasonable mechanic should be able to do the installation. We’ve dropped cams in quad engines, and if you aren’t changing any valve train parts, the job is pretty quick and easy.

This Bikeman Pro R is still fun to carve turns with. Like many machines with straight paddles, it does tend to want to go straight when you mash the power, but you adapt.


With the Stage 3 kit, all the easy and budget ponies have been rounded up. Those last 30 horsepower require the Big Valve AirXtreme head kit. You can buy the AirXtreme head kit alone for $5995.95, or it is included in the $7799.95 Stage 4 kit. Starting with a stock Polaris head casting, the head is ported and the combustion chamber is reshaped. The valves are larger, and the entire valve train is replaced. That price may sound like a lot of money, but you are basically modifying four 450cc quad heads and replacing the cams and valve-train parts. 

If it was our money we’d stick with the 300 horsepower, but if you want all the snorting horses available, you need the head modifications.


After all of the Stage 4 mods, Bikeman felt the need for Hostile forged lightweight wheels and monster Sand Tires Unlimited 31-15 Blackbird Pro paddle tires. The paddles come with every other paddle removed. In addition, the tires have a competition cut to make the tires lighter. STU doesn’t offer that service, but there are companies that specialize in it. For the front there are STU 32-15, The Lead Screw smooth tires.

All of the mods work together to make a bunch of ultra-responsive power. The BMP Polaris Pro R starts easily and has just a bit of rumpity idle. It is loud. Without ear protection the lack of fuel in the tank was not a problem. We’d like to see a quieter exhaust.

Of course, once the ECU is modified the car is restricted to closed-course competition. None of the mods hurt that stunning low-rpm instant response of the Pro R. There is no waiting for the power. It builds rpm like crazy. It won’t actually pull the front wheels off the ground on smooth, flat sand, but it feels like it wants to!

It slams you back in the seat and rips hard. Without the giant Sand Tires Unlimited paddle tires, much of the acceleration would have gone up in wheelspin. As it is, you can see the paddles literally wrinkle the side walls with the hook the tires grab.

Acceleration is best described as violent or at least breathtaking. If you have a little rise, the car is easily coaxed into a giant power wheelie. Having all this power on pump gas with a stock compression engine and no forced induction is most impressive.

So many modified engines we have experienced are fussy and finicky or temperamental. We didn’t ever get that feeling. The only feeling was the addiction of acceleration. Once you feel building speed like this, you can’t keep your foot out of it. You just keeping searching for a bowl, a climb or smooth sand that will allow you to unleash all the horses and let them play.

If you are that sort of addict, Bikeman Performance has what you need.


Bikeman Performance: www.bikemanperformance.com

Torque Link level 4 ECU tune $299.95

SNYPER clutch weights $349.95

Brian Crowler Stage 4 cams (Bikeman exclusive spec) $999.95

Air Extreme head $5,995.95

Pro R stage 4 bolt-on Performer kit $7,799.95

Other modifications:

Hostile forged wheels: www.hostilewheels.com

HF13 Outlaw 15-10 rear $415

HF13 Outlaw 15-8 front $408

Sand Tires Unlimited: www.sandtiresunlimited.com

31-15 Blackbird Pro paddle tires with tread (cuts weight reduction) $608.76

32-15 The Lead Screw smooth front tire $351.90

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