• Bikes for Sale
  • News
  • Buyer’s guide
    • Buy a Motorcycle
    • First Rides & Reviews
    • Specs, Prices & Others
  • Lifestyle
    • Concepts & Custom
    • Electric Motorcycles
    • Events
    • Motorsport
    • Tips & Stories
    • Travel
  • Locals
imotorbike logo
  • Bikes for Sale
  • News
  • Buyer’s guide
    • Buy a Motorcycle
    • First Rides & Reviews
    • Specs, Prices & Others
  • Lifestyle
    • Concepts & Custom
    • Electric Motorcycles
    • Events
    • Motorsport
    • Tips & Stories
    • Travel
  • Locals
  • Facebook

  • Instagram

  • X (Twitter)

  • YouTube

  • LinkedIn

  • RSS

The World’s First Oval Pistons Developed By Honda
Sathurshan
January 9, 2020

In 1979 Honda produced the world’s first engine which featured oval pistons with the introduction of the NR500 Grand Prix racer. The oval pistons later found their way in the 1980 NR750 endurance racer and the road going NR.

Honda NR500 Oval Pistons

Honda NR500 Oval Pistons in the Engine Assembly | Photo Credit: HRC

The Honda NR500

Honda’s 70s journey is what led to the creation of the oval pistons. In the 60s Honda had a successful Grand Prix journey before their absence in the early 70s. They decided to return to Grand Prix motorcycle racing in the late 70s. Honda realised during their absence Grand pix have taken over by two-strokes bikes compared to their four-stroke equivalent.

To compete in the Grand Prix  Honda preferred working on four-stroke engines. During the development stage, they looked into increasing the number of cylinders. Unfortunately, the Grand Prix rule allowed only a maximum of four cylinders. Honda engineers got back to the drawing board and tried to develop a V8 engine in the form of a four-cylinder engine.

Honda NR500 oval pistons

Honda NR500 Engine

The result of this was the NR500 under the NR (New Racing) series, featuring oval pistons with 32 valves and eight con-rods. That meant two con-rods per piston and eight valves per cylinder! On top of that, Honda engineers made all of these fit into a regular four-cylinder engine!

Honda NR500 oval pistons

Honda NR500 Assembly

Honda NR500 oval pistons

Honda NR500 | Photo Credit: Cycle World

The bike produced 130 bhp at 20,000 rpm, but it did not succeed on the track. The NR500 is one of the radical motorcycles in history that failed.  Honda later went ahead with using the NS500 two-stroke machine.

The Honda NR750

Honda GP, NR500 and NR750

Photo Credit: 95 Custom

Honda used the same technology in the NR750 endurance racer later in the 1980s. A few years later in 1992 Honda decided to produce 300 units of the road-going version of the NR750 as the Honda NR. The 750cc road-going NR’s featured elliptical-shaped pistons with long curved sides. The NR500, however, had oval pistons with straight sides.

NR500 Oval Piston

NR500 Oval Pistons | Photo Credit: Honda Global

NR750 Honda Oval Piston

NR750 Oval Pistons | Photo Credit: Honda Global

honda nr500 engine

Oval Piston Components

The 750cc 90-degree V-four engine with oval pistons allowed eight valves per cylinder just as the older NR500 engine. The engine generated a vast amount of power as the air/fuel ratio, and the compression in the cylinder increased dramatically compared to an ordinary V-four engine.

NR750 oval pistons

NR750 Engine Assembly | Photo Credit: On Road Zone

oval piston

Honda’s 750cc NR engine | Photo Credit: Honda

The stock road-going 750cc NR was capable of producing 125 bhp at 14,000rpm. When released, the NR cost $50,000. It is considered normal for a rare collectable motorcycle which has one of the most unique engineered and design quirks until today.

nr750 engine

Honda NR750 Engine using Oval Pistons | Photo Credit: Visor Down

Related Items70sfeaturedHondaNRNR500NR750Oval PistonPiston
To read the full story
login with google
login with facebook
or
Create an account for free
This won't cost you.
by clicking this button you agree to iMotorbike's visitor agreement
Already have an account? Sign in here
Click here to get notified on every new article
News
January 9, 2020
Sathurshan

A Mechanical Engineer with an addiction to the smell of petrol and loves anything automotive.

Related Items70sfeaturedHondaNRNR500NR750Oval PistonPiston

More in News

Alex Marquez Suffers Broken Hand in Dutch GP Crash

Hazique ZairillJuly 4, 2025
Read More

Jorge Martin’s 2026 Move Blocked Over Aprilia Contract

Michelle LiewJuly 2, 2025
Read More

India’s Gojek Moment? MoRTH Greenlights Bike Taxis

Michelle LiewJuly 2, 2025
Read More

Shoei J.O2 Helmet Combines Retro Style with Modern Safety

Michelle LiewJuly 2, 2025
Read More

Hakim Danish Gears Up for Magny-Cours Debut

Michelle LiewJuly 2, 2025
Read More

The importance of Wearing Gloves While Riding Motorcycle

Hazique ZairillJuly 2, 2025
Read More

Why ABS Matters: Life-Saving Tech Now Mandatory on Malaysian Motorcycles

Hazique ZairillJuly 2, 2025
Read More

FEAR-NONE Unleashes Summer 2025 Biker Collection

Michelle LiewJuly 1, 2025
Read More

Maeving RM1S Redefines the Electric Motorcycle

Michelle LiewJuly 1, 2025
Read More

Ruroc Raises the Bar with the Eox Carbon Helmet

Michelle LiewJuly 1, 2025
Read More

Kawasaki Unveils Hydrogen-Powered Motorcycle at Suzuka

Michelle LiewJuly 1, 2025
Read More

Diogo Moreira Marks As First Ever Brazilian Moto2 Winner 

Hazique ZairillJuly 1, 2025
Read More
We want to buy your bike Join us on Telegram
Scroll for more
Tap

Join us on Facebook

  • Popular

  • Latest

  • Comments

  • Motorcycle Loan Calculator & Motorcycle Rates Malaysia
    Buyer's guideJuly 1, 2025
  • Indian Motorcycle Officially Launched in Malaysia
    Buyer's guideJune 23, 2025
  • 6 Best Cruiser Motorcycles in Malaysia You Can Get Your Hands On
    Buyer's guideJune 19, 2025
  • Hanway Heritage 400 Review: A Budget Bobber That Turns Heads
    Buyer's guideJune 30, 2025
  • YADEA GT20 Debuts in Malaysia: Price Starts at RM4,998
    Buyer's guideJune 18, 2025
  • Yamaha Y15ZR V2 Review: Still the People’s Moped After All These Years
    Buyer's guideJune 13, 2025
  • Kawasaki Corleo: The Four-Legged Ride of the Future
    NewsJune 25, 2025
  • Alex Marquez Suffers Broken Hand in Dutch GP Crash
    MotoGPJuly 4, 2025
  • Jorge Martin’s 2026 Move Blocked Over Aprilia Contract
    NewsJuly 2, 2025
  • India’s Gojek Moment? MoRTH Greenlights Bike Taxis
    NewsJuly 2, 2025
  • Shoei J.O2 Helmet Combines Retro Style with Modern Safety
    NewsJuly 2, 2025
  • Hakim Danish Gears Up for Magny-Cours Debut
    NewsJuly 2, 2025
  • The importance of Wearing Gloves While Riding Motorcycle
    LifestyleJuly 2, 2025
  • Why ABS Matters: Life-Saving Tech Now Mandatory on Malaysian Motorcycles
    Buyer's guideJuly 2, 2025
  • MV Agusta Lucky Explorer Project 9.5: testing the Schiranna prototype - news.iNthacity: More Top Breaking News and Popular Stories To Stay Informed says:

    […] Michelle Liew […]

  • CFMOTO 450SR to enter Malaysia in March 2023 at RM29,300 - news.iNthacity: More Top Breaking News and Popular Stories To Stay Informed says:

    […] Michelle Liew […]

  • Suzuki V-Strom now available in Malaysia at RM81,900 - news.iNthacity: More Top Breaking News and Popular Stories To Stay Informed says:

    […] Michelle Liew […]

  • Colin says:

    I hope they make the Dax street legal. Love to…

  • Mohd Razi bin Rosli says:

    Adv 150cc

  • Nena Maxberry says:

    Just curious what they would retail for

  • Adam Kenny says:

    RM4159 for the front fork is it?

Categories

  • Buyer's guide
    • First Rides & Reviews
    • Specs, Prices & Others
  • cafe racer malaysia murah
  • CSR Programme
  • Electric Motorcycles
  • Electric Motorcycles
  • Industry
  • Industry
  • Kedai Motor
  • Lifestyle
    • Concepts & Custom
    • Electric Motorcycles
    • Events
      • EICMa
    • Helmet
    • Motorsport
      • ARRC
      • CubPrix
      • Moto3
      • Motocross
      • MSBK
      • WSBK
    • Tips & Stories
    • Travel
  • Moto2
  • Motor Murah
  • News
    • Locals
    • MotoGP
    • Scoop
  • Review
  • Scoop
  • Scoop
  • Tips & Tricks

Corporate

About Us
Terms of Use
Privacy Policy
Disclosure Policy
Contact Us
SUBSCRIBE NOW!

2024 iMotorbike World Sdn. Bhd.(1205246-M). All rights reserved.

Chinese manufacturer Niu introduces new electric bikes at CES
Monster Energy Yamaha’s Franco Caimi finishes 12th place in Stage 5
Nak Jual Beli Motor 😊 ?
WhatsApp
Hi iMotorbike 😊
Open chat