
It had to happen. The Motus V4 Baby Block®, is a 100 cubic inch (1650cc), 180 horsepower, V4 engine that Motus developed for their new line of comfortable American sport bikes. As news of the motorcycles spread during development, hot rodders all over the world were looking at the little V4 and asking, “Hey, could I just buy the engine?” It just so happens, you can and it’s starting to show up in all sorts of project applications like boats, race cars and many other motorcycles. And now, courtesy of an engine swap kit from Pratt & Miller Engineering and Motus, you can install it in the Polaris RZR XP1000.
“We are really excited about the big performance gains seen after installing the American V4â€, commented Lynn Bishop, VP Engineering Services at Pratt & Miller Engineering. “The stock engine is great for many drivers, but the added power is a game changer in terms of hole-shots and acceleration out of turns. And, it has a visceral, American muscle sound that really sets it apart.â€
… the MV4-ZR Crate Engine Kit offers over 60% more power than the stock engine and 25% more power than anything in the current RZR® line-up.

Pratt & Miller Engineering played a big role in the development of the Motus Motorcycle. While many of you are probably familiar with the company from their Corvette racing team that has been enormously successful, when I was at their headquarters for the unveiling of the Motus sport bike, I found they are involved in far more than their multiple racing projects, they’re a multi-faceted engineering powerhouse that designs, engineers and manufactures world-class vehicles, components and software, so if they’re on the team to do an engine swap, you can bet you’ll get a first class kit.
Testing is underway to validate the durability of components in a wide range of driving conditions. Once Motus and Pratt & Miller are satisfied with the final package and the bill of materials is finalized, pricing and availability will be announced. All MV4-ZR Crate Engine kits will be installed by factory-trained American V4 installers or dealers being sought now.
Swapping the 110 hp stock engine for a 180 hp American V4 changes your XP1000 into a serious hot rod, so it has to be done right. The MV4-ZR turn-key engine swap kit will come with everything needed for professional installation by a factory-trained technician, either at a participating Motus dealer or a quality local SxS dealer/shop.

The project goal was to dramatically increase powertrain performance of the RZR® XP1000 with as little modification to the chassis or other components as possible. Pratt & Miller started with a stock 2015 XP1000 and designed everything needed to re-power it with the Motus MV4 “Baby Block†engine, leaving as much stock as possible.
Vehicle Quick Specs:
Chassis – 2015 Polaris® RZR® XP1000 EPS
Engine – Motus V4 Baby Block®, naturally aspirated
Engine swap kit – Pratt & Miller Engineering
Gearbox – Stock
Clutch – STM
Exhaust – Pratt & Miller Engineering
Intake – Pratt & Miller Engineering
Wheels – Stock
Tires – Stock
Suspension – StockThe mighty V4 Baby Block® delivers impressive power and torque using the same architecture found in the most reliable and competitive small block V8 engines in the world.
- overhead valves, pushrods
- chain driven cam-in-block
- hydraulic valvetrain
- closed loop fuel injection with electronic throttle control
- 180 bhp, 123+ ft. lbs torque, naturally aspirated
- 140 lbs weight
This swap kit for the Polaris side-by-side is classic hot rodding, and given the interest in this V4, and its potential for increased power, I have a feeling we’ll be seeing it in a lot more applications very soon. In fact, you can count on it.

I was intrigued, until I saw the price elsewhere.
I also was very interested until just this past weekend a yamaha yxz1000r with only exhaust and a 40 shot smoked the mv4 razor BAD, That means anybody can buy a stock yxz1000 for 20k and with only $1000 in mods that take maybe 5 hrs to install will beat any rzr 1000 with the mv4 conversion that they have spent well over 35k on.
For 8100 you can have a&s put an apex in your Rzr that dyno out to 350 hp ….. No brainier there