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The unofficial MO motto is “More is more.” So, naturally we were happy to learn at the International Motorcycle Shows Long Beach media day last week that Indian has released the Thunder Stroke 116-Cubic-Inch Stage 3 Big Bore Kit. What’s that, you say? Well, how does a claimed 15% increase in torque and a 20% bump in horsepower strike you? Yeah, us, too. So, if your Thunder Stroke 111 has started to feel a little anemic after reading this paragraph, moto-salvation is at hand.

For a retail price of a buck shy of $2,000 (plus installation), the Thunder Stroke 116-Cubic-Inch Stage 3 Big Bore Kit provides you with a set of domed pistons and matching cylinders. Mated to those are a set of lumpy cams and stronger valve springs. The increased intake demands are taken care of by a new throttle body and intake manifold. A set of beefier clutch springs to help deliver the increased power to the rear wheel. Rounding out the kit is an ECU flash to update the EFI-mapping to handle the increased cubes. However, there are some additional requirements for the kit. In order to install the Stage 3 kit, you’ll also need Indian’s Stage 1 Performance Air Cleaner and Thunder Stroke High Flow Air Cleaner on the intake side, while the spent gasses are handled by the Indian Stage 1 Slip-On Exhaust Kit.

Here are all the goodies. Of special note is the inclusion of a new throttle body (bottom right), which is relatively rare in a kit like this.

Since the kit was announced at the Long Beach IMS show, Indian took advantage of the opportunity to put a MOronic butt in the seat of a Chieftain Limited from the company’s demo fleet. So, what follows is an impression from the saddle during a 45-minute ride.

From the instant the engine thundered to life, it was clear that the displacement was more than stock. The Stage 1 slip-ons had a familiar-but-deeper sound. The idle-speed was set a little lower than I like, causing the piston pulses to hit with a little bit of irregularity and making me think the engine was going to stall. Of course, the engine never did, but I’d be tempted to bump the idle up a couple hundred rpm to smooth things out a bit.

Out on the road, the 116 cubic inches impressed me with what hasn’t changed. Unlike many aftermarket big-bore kits which will only function well at full-throttle, the Stage 3 Kit was tractable throughout the rpm range. At every rpm range, rolling on the throttle generated more speed than the stock displacement – with almost the same amount of finesse. However, when in first gear just above idle, I did notice some snatchiness when trundling along in traffic. Commuters take note. When transitioning from off-throttle to on-, the fuel metering was spot on. I purposely tested going out of and back into the throttle on a series of corners in an attempt to get the engine to lurch and was rewarded with smooth transitions every time.

Boom! Yes, those 5 additional cubes make a difference.

Out on the highway, when it came time to pass traffic in top gear, I found that if the rpm were below 3,000, the 116 preferred to have the throttle rolled open rather than snapped WFO. While the engine didn’t bog when the butterfly valve flipped all the way open, it didn’t feel like it was pulling as hard below 3,000 rpm. Rolling on the throttle elicited a much stronger response, as if the injection couldn’t handle the instantaneous increase in flow unless the throttle was transitioned to all the way to the stop. When this technique was applied, the 116 pulled like a completely different animal from the 111.

So, if you’re a horsepower junkie with a Thunder Stroke 111 engine parked in your garage – and you already have the Stage 1 kits installed – the Thunder Stroke 116-Cubic-Inch Stage 3 Big Bore Kit may be just what you’re looking for. Others will need to consider the cost of adding the Stage 1 kits to the mix before considering the 116. Since a stock Thunder Stroke 111 made 74.2 hp on the MO dyno, we’d expect the horsepower to jump to 89.0 and torque to 118.2 lb-ft. Yes, the fuel mapping could be a little tidier to maintain the same level of smoothness available from the original 111 cu.-in. displacement, but the abruptness just above idle is more of a niggle than a problem. The softness in the full-throttle below 3,000 rpm in top gear was mitigated by simply rolling on the throttle instead of whacking it open – something a rider would be able to easily adjust to. The rest of the time, the Stage 3 Kit can be ridden just like the stocker – only with way more power.

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