Ninja ZX-4RR, A Compact Superbike From Kawasaki

This new Kawasaki Ninja ZX-4RR KRT 400cc four looks exactly like a true superbike, save for one small giveaway. It sports dual discs and radial-mount calipers, as well as all the other visual characteristics of a sportbike with racing heritage. At first, all I could make out was how slim the chassis was, holding the right end of its sculpted swingarm. I didn’t need to worry because the upright is made of steel, which is three times as stiff as the aluminum used in standard sportbike chassis (as well as the remainder of the tubular chassis and swingarm). When Honda added a steel frame to its 600 Hurricane in 1987, we applauded the company for saving money. How little we knew—within a short period of time, 600s became costly and feature-rich.

As I’ve previously mentioned, motorcycle sales plummeted in 2008 when so many people’s disposable incomes were sucked dry. In response, business tested the market with novelties like $13,000 electric scooters before putting on a mechanical variety show. There are few takers.

Only when the manufacturers understood that consumers’ preferences hadn’t really changed as a result of high insurance rates and tight budgets (they still wanted motorcycles’ typical features but couldn’t afford to spend $18,000 for them). Recently, in response, motorbikes with exceptional performance but streamlined designs—many of them Twins—have been made available at rates that are easier for people to afford. Additionally, the word “sportbike,” a trigger for the insurance business, has been purposefully avoided.

More buyers result from the Superbike Song’s lower price.

Okay, we must admit that we adore the new mid-displacement twins and their innovative approach to performance delivery, which includes flat torque curves, lighter weight, and mind-reading response. But what if we also adore the In-Line Four’s high, lovely song? What if we had a lifelong love affair with sportbikes? Let’s build a bike with a displacement that won’t scare off insurers, and then see how much of the classic full superbike design we can implement at a price that most riders can afford.
There’s also that to take into account. Anything that resembles a superbike will have to deliver substantially more performance because there are currently inexpensive bikes in the 300-400cc displacement range. We need our hypothetical product to be “super” to at least that extent.

Here are the specifications for the 2023 Kawasaki Ninja ZX-4RR KRT, even though you have probably already read information about it in advance: Having a short, quick-turning 54.3-in. wheelbase, a claimed curb weight of 414.5 lb (dry weight will be less), and the appropriate sportbike steering geometry of 23.5 degrees rake and 3.8 inches tail. 12.6 to 1 compression ratio. The sheet informs us that this 16-valve engine’s peak torque is 26.5 lb.-ft. At 11,000 rpm, translating to a horsepower at peak torque rpm of 55.5 while coyly leaving out horsepower for the US market. Mathematically calculating the brake mean effective pressure (BMEP), also known as stroke-averaged net combustion pressure, at this rev range yields the decidedly un-sportbikesh result of 164 psi, or roughly 15% less than a full-boogie sportbike number. If we assume that this engine’s torque is flat as a board (i.e., the same at peak power as at peak torque), peak power at 13,500 can’t be greater than 68 hp. BMEP peaks where torque peaks. However, we discovered from the European press that the 400’s advertised output is between 77 and 78 horsepower. Although we’d prefer to end this war, we don’t currently have the knowledge necessary to accomplish so.
There must always be more to come the following year. We aim to sell this product to as many customers as possible by giving it the power to stand out from the competition (thus the word “super”) without squandering the budget on pointless race track features.

Other manufacturers will enter the market and increase performance if this model is successful. Should a little be good, However, each year’s incredible performance boost (forged pistons, finger followers, fracture-split titanium rods), as we’ve seen in the sadly defunct sportbike past, came at a cost. Additionally, the professional staff at the insurance companies were prepared to greet us (“If you’ll just hand me a check now…”).

What Is the Ninja ZX-4RR’s Potential Power Output?

What potential uses could such an engine have? A similar engine fitted with high-quality components could reach a maximum speed of 17,500 rpm and produce a power output that was oh-so-close to 100 hp at piston speeds we saw frequently in the early years of this century. This model’s redline is 16,000 rpm. But let’s avoid it. We don’t need to go there because that item is readily available on the used market. We want to have fun on a budget-friendly, insurable motorcycle with a guarantee and classic Superbike good looks.

As I’m sure you’ve already predicted, the once-exotic electronic rider aid features have largely devolved into banal computer chip suburbs that we now take for granted.

What About the KOVE 400R, though?

Many people are tempted to just remark, “When they establish a showroom up the street from me and customers start coming out on new bikes, then I might have a look,” because there are so many descriptions of Wahoo Chinese-made motorcycles available. But what else? Vaporware, garbage
Bosch is the manufacturer of the digital fuel injection system, and the top speed is listed as 136 mph. In an uncommon move, the steering geometry is listed as three digits rather than the typical two. The steering angle is 28 degrees, while the rake angle is 25 degrees. Does this imply that the steering axis is not parallel to the plane of the fork tubes? Maybe. It is 3.87 inches long.


Don’t be shocked by the closeness of the statistics because there aren’t many engine design trade secrets working at this low performance level. New producers continue to analyze the output of the long-standing producers, as they always have. Once a firm has product lines that are profitable, it can afford to have a capable R&D department. When Mr. Honda went off beaming on all his tool-buying trips in the 1950s, that is exactly what he was getting up to. He made sure his engineers had the most up-to-date tools so they could independently ascertain the truth. They started learning stuff that nobody else knew, and in 1961 Honda won its first FIM world championship (the 250). Many more were still to come.

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