70 hp, 254 lbs: Two-Stroke Race Replica Restomod from Japan…
Built from 1987-1999, the Honda NSR250R was a street-legal two-stroke race replica powered by a liquid-cooled 249cc 90° V-twin with Honda’s power-valve system and nikasil-sulfur lined cylinder bores — hence the NS in NSR. While we weren’t lucky enough to receive these bikes in the States due to emissions regulations, most of them are now old enough to be imported, titled, and registered in the US!
Introduced in 1990, the MC21 was the third-gen version of the NSR250R, featuring a new frame and iconic “gull-arm” swingarm, along with some high-tech electronic wizardry:
“The bike uses a PGMIII ECU that is coupled to a throttle-position sensor and gear-position sensor. With those inputs plus rpm, the ECU monitors and controls the power valves and ignition timing to give optimum performance. Very trick stuff for 1990!” –Motorcycle.com
In fairly recent comparison of three 250cc two-stroke race replicas from this era, the MC21 NSR250R swept the field, scoring high marks both no the track and in the paddock:
“If I were in the market to buy a brand-new motorcycle or an old-school two-stroke street-legal 250, I would buy the red-and-white Moto2 Imports NSR250. I’ve never smiled so much on a bike before; it sounded like a swarm of bees. It was an awesome experience.” –Cycle World
For 1992, a limited amount of 1500 Rothmans SP models were released, sporting the iconic cigarette company livery:
“The 1992 Rothmans SP is one of the most coveted two-strokes of all time.” –Moto2 Imports
Enter our new friend from Japan, Susumu Sato (@nsr_mc28_mc21), who owned a Honda NSR250R 25 years ago…only to have it stolen and never recovered. Fast forward two and a half decades, and Susumu decided to get back in the saddle. Though the NSR Rothmans specials are highly rare and expensive even in Japan, Susumu managed to pick up a non-running donor and spent the next three years restoring and customizing it into the stunning machine you see here.
Susumu says his inspirations were as varied as modern MotoGP bikes, the 30th anniverary edition Honda CBR1000RR-R Fireblade SP, and the F-15 fighter jet. Through a flurry of modifications detailed below, horsepower has been increased from the stock output of 45 hp to 70 ps (69 hp), while weight is down nearly 40 pounds — from 132 kg (291 lbs) to 115 kg (254 lbs)!
As you can imagine, there were many challenges to completing the build, including financial sacrifices (Susumu is thankful to his wife for understanding), but the result is well worth it — a modernized NSR250R SP that performs as well as it looks:
“There is an acceleration that doesn’t seem like a 250cc, and it’s almost an illusion that you’re challenging the 600cc super sports. When braking into corners, it has amazing stopping power, and in corners, it handles just as you want it to.”
Below, we talk to Susumu for the full details on the build!
Honda NSR250R Restomod: Builder Interview
• Tell us a little bit about yourself, your motorcycle history, and your workshop.
My name is Susumu Sato. I bought a broken bike and continued to restore and customize it at home for three years.
• What is the make, model and year of the donor bike?
1992 Honda NSR250R SP Rothmans.
• Why was this bike made?
Twenty-five years ago, I had the same motorcycle (NSR250) as now, but it was stolen. As an adult, remembering the way it rode 25 years ago, I really wanted to ride again.
• What inspired the design concept and construction?
Designed with inspiration from MotoGP style, Honda CBR1000RR-R, and F-15 fighter motifs.
• What custom work has been done on the bike?
Front: PC40 SHOWA HRC inverted radial fork
Rear: Öhlins, TTX processing installation, Pro arm processing, NX5 5.5J Marchesini wheels, Bridgestone S21 180
BABYFACE (Sato Racing) handlebars, Domino quick-turn throttle, Accossato racing clutch lever, JHA rear-sets
● Electrical system
MC28 harness (processed without handle lock unit), MC28 PGM4 Intake system, MC28 carb, T2R rectifier, Tyga carbon ram air style cab box, DMR solenoid jet, JHA cab setting kit
● Exhaust system
JHA RS Force 304 chamber
Reed valve case primary compression processing, cylinder processing, T2R rebuild core crankshaft, MC21 late crankcase and deburring, oil pumpless and T2R blind plate, mission cover painting, DMR lightweight driven gear aluminum housing, MC21 lightweight flywheel processing, Tyga woodruff key 1 degree, engine drive system titanium bolts
Front: Brembo RCS19 radial master cylinder & CNC racing caliper, Sunstar works expand disc, Accossato CNC riser bar tank, AC line mesh hose
Rear: Brembo master, Sunstar racing disc, tankless master, AC line mesh hose
● Drive system
ISA 15T sprocket, Affirm 38T sprocket, MC21 mission
DMR lightweight clutch housing and clutch pressure plate, various bearing replacement
Thermostatless Cooling system, DMR racing impeller and mechanical seal, T2R radiator hose
T2R type 2 full cowl and screen and yellow film processing, Tyga Rothmans FRP tank
Burning Blood NSF100 FRP Sheet and T2R Sheet Sponge
T2R rear carbon fender and carbon headlight cover, general-purpose Aprilia RS4 carbon winglet processing, SC59 early front fender
Cutting and self-painting
MC21 frame processing & polishing, MIXS seat rail & battery box processing, Accossato CNC tank cap, various titanium bolts
• Do you have a nickname for your bike?
• Any thoughts on horsepower, weight and/or performance numbers?
Horsepower 70ps / Weight 115kg
• Can you tell me what it’s like to ride this bike?
There is an acceleration that doesn’t seem like a 250cc, and it’s almost an illusion that you’re challenging the 600cc super sports. When braking into corners, it has amazing stopping power, and in corners, it handles just as you want it to.
• Was there anything you were particularly proud of during this build?
Although it is made in Japan, the value and price of the NSR250 is high even in Japan, so not everyone can do it. I feel lucky and proud to have purchased it.
• Is there anyone you would like to thank?
My wife. We have been indebted in various situations, such as providing funds and repair places.
Build Process: Gallery
Follow the Builder: @nsr_mc28_mc21