Uploaded May 2026 | Updated September 2026, 2 weeks ago
Kawasaki is famous for its legendary Z1, but did you know they almost released a 900cc twin-rotor Wankel that would have blown it away? 🏍️💨
In this video, we dive into the secret history of the Kawasaki X99, the water-cooled rotary powerhouse that output nearly 87bhp - more than the Z1 and far beyond the Honda CB750 or Norton Commando of the time. We look at the engineering challenges, the 'wobbly' technical hurdles described by project leader Mr. Tsugio Takarabe, and why the 1970s oil shock ultimately killed the project after just one track test.
Could this have been the fastest bike on the road in 1974? Let’s find out.
In this video:
The origin of the Felix Wankel design.
Kawasaki's "X99" vs. the "New York Steak" (Z1).
Why the X99 suffered from fuel efficiency and seizing issues.
A comparison of stats: Kawasaki’s Rotary vs. the competition.
The legacy of Tsugio Takarabe and his move to the Vulcan V-twin.
Support the channel: If you enjoyed this deep dive, please like, comment, and share!
You can also support 3Phils for just 99p a month by becoming a 4th Phil for early access: youtube.com/@3Phils/join
Watch more Wankel history:
youtube.com/playlist?list=PLQz972c3FW_YRObVV7H-v91xYvAOMYX4k&si=Scfnx5uoFgcK963-
Don't forget to join us on Facebook too!
facebook.com/profile.php?id=61550349542826
Credits and links:
Kawasaki Square Four - Hifumi Watanabe
youtube.com/watch?v=w9hGeooI42Q
Kawasaki X-99 Product Designers Talk "ROTARY ENGINE CHALLENGE" - Kawasaki
youtube.com/watch?v=1mrH5FqTjvU&t=9s
Norton Rotary Classic no. 11 of 100 - Silk TV
youtube.com/watch?v=CH-8k8uMHhY
1975 Suzuki RE5 - Bill Johnson
youtube.com/watch?v=ZZ5WIHclk68
How to Hypermile - 4 Tips for Running Out of Gas - FortNine
youtube.com/watch?v=IFANWojM8LU
X-99 Prototype Rotary Engine KAWASAKI - TAKAO AOKI
youtube.com/watch?v=b8rIHBNVvCI&t=2s
Guy Martin onboard a ROTARY bike - I Like Motorbikes
youtube.com/watch?v=SHtz8tlavY0&t=780s
Chapters:
0:00 The 1970s Rotary Race
0:42 How the Wankel Engine Works
1:15 Kawasaki's 900cc Powerhouse
1:52 Meet the Designer: Tsugio Takarabe
2:20 Project X99: The Meatless Code Name
2:38 Engineering Challenges & Squeezing it In
3:21 The 'Wobbly' Problem: Efficiency & Seizing
4:23 The Oil Shock & The End of Development
5:11 X99 vs. The Competition: The Stats
6:28 Why the Z1 Won the Day
6:53 Kawasaki's Heritage & Other Rotary Bikes
7:29 Support 3Phils & Outtakes
#Kawasaki #Wankel #RotaryEngine #MotorcycleHistory #ClassicBikes #X99 #3Phils #VintageKawasaki #Z1 #EngineeringHistory
Kawasaki is famous for its legendary Z1, but did you know they almost released a 900cc twin-rotor Wankel that would have blown it away? 🏍️💨
In this video, we dive into the secret history of the Kawasaki X99, the water-cooled rotary powerhouse that output nearly 87bhp - more than the Z1 and far beyond the Honda CB750 or Norton Commando of the time. We look at the engineering challenges, the 'wobbly' technical hurdles described by project leader Mr. Tsugio Takarabe, and why the 1970s oil shock ultimately killed the project after just one track test.
Could this have been the fastest bike on the road in 1974? Let’s find out.
In this video:
The origin of the Felix Wankel design.
Kawasaki's "X99" vs. the "New York Steak" (Z1).
Why the X99 suffered from fuel efficiency and seizing issues.
A comparison of stats: Kawasaki’s Rotary vs. the competition.
The legacy of Tsugio Takarabe and his move to the Vulcan V-twin.
Support the channel: If you enjoyed this deep dive, please like, comment, and share!
You can also support 3Phils for just 99p a month by becoming a 4th Phil for early access: youtube.com/@3Phils/join
Watch more Wankel history:
youtube.com/playlist?list=PLQz972c3FW_YRObVV7H-v91xYvAOMYX4k&si=Scfnx5uoFgcK963-
Don't forget to join us on Facebook too!
facebook.com/profile.php?id=61550349542826
Credits and links:
Kawasaki Square Four - Hifumi Watanabe
youtube.com/watch?v=w9hGeooI42Q
Kawasaki X-99 Product Designers Talk "ROTARY ENGINE CHALLENGE" - Kawasaki
youtube.com/watch?v=1mrH5FqTjvU&t=9s
Norton Rotary Classic no. 11 of 100 - Silk TV
youtube.com/watch?v=CH-8k8uMHhY
1975 Suzuki RE5 - Bill Johnson
youtube.com/watch?v=ZZ5WIHclk68
How to Hypermile - 4 Tips for Running Out of Gas - FortNine
youtube.com/watch?v=IFANWojM8LU
X-99 Prototype Rotary Engine KAWASAKI - TAKAO AOKI
youtube.com/watch?v=b8rIHBNVvCI&t=2s
Guy Martin onboard a ROTARY bike - I Like Motorbikes
youtube.com/watch?v=SHtz8tlavY0&t=780s
Chapters:
0:00 The 1970s Rotary Race
0:42 How the Wankel Engine Works
1:15 Kawasaki's 900cc Powerhouse
1:52 Meet the Designer: Tsugio Takarabe
2:20 Project X99: The Meatless Code Name
2:38 Engineering Challenges & Squeezing it In
3:21 The 'Wobbly' Problem: Efficiency & Seizing
4:23 The Oil Shock & The End of Development
5:11 X99 vs. The Competition: The Stats
6:28 Why the Z1 Won the Day
6:53 Kawasaki's Heritage & Other Rotary Bikes
7:29 Support 3Phils & Outtakes
#Kawasaki #Wankel #RotaryEngine #MotorcycleHistory #ClassicBikes #X99 #3Phils #VintageKawasaki #Z1 #EngineeringHistory
