Two-Stroke Honda Grom by Jesse Davis

Honda Grom 2-Stroke

YZ250-powered Honda Grom…50 horsepower!

The Honda Grom has been more successful than anyone ever imagined. The overgrown monkey bike won Motorcycle USA’s Motorcycle of the Year award in 2014, and the 125cc four-speed machine has attained a cult following of epic proportions. However, the stock bike leaves much to be desired in the performance department, with only 8.6 horsepower on tap.

Honda Grom 2-Stroke

Enter Jesse Davis, a lifelong road racer from Austin, Texas, who works for none other than Roland Sands Design. Jesse had what we can only classify as a stroke of genius when he decided to shoehorn a 2002 Yamaha YZ250 two-stroke motor into his 2014 Honda Grom, more than quintupling power output from 8.6 to 50+ horsepower!

Honda Grom 2-Stroke

Below, we get the full story on this two-stroke giant-killer.

YZ250-Powered Honda Grom:  Builder Interview

Honda Grom 2-Stroke

Tell us about yourself, your shop, and your history with motorcycles?

I’m Jesse Davis, I’m from Austin Texas, currently living in Long Beach, CA. I’ve been road racing motorcycles for 30 years. I’ve been building cars and motorcycles for most of my life. I currently work for Roland Sands Design, building custom motorcycles.

Above is a racer that Jesse built a few years ago, winning a national championship on it. It’s a 1098 Ducati chassis with an air-cooled 1000ds motor. 118hp/300 lbs wet.
What’s the make, model, and year of the bike?

The bike is a 2014 Honda Grom, with a 2002 Yamaha YZ250 2 stroke motor.

Honda Grom 2-Stroke

Why was this bike built?

I built this bike to have a personal super fun streetbike.

Honda Grom 2-Stroke

What was the design concept and what influenced the build?

I didn’t really have a design concept in mind other than I love two strokes, and the idea was original, as there haven’t been any other 2 stroke Grom’s built. Especially not any with 50+ hp. The paint job was inspired by Christian Sarron’s Gauloises Yamaha 250 GP bikes from the 1980’s. Including the green number plate, signifying the 250cc class.

Honda Grom 2-Stroke

What custom work was done to the bike?

The modifications are extensive. Frame was cut down the backbone and modified and braced. The complete engine cradle from the YZ frame was cut and sectioned and installed onto the Grom frame. It is completely removable for easy servicing of the engine.

Honda Grom 2-Stroke

The forks are from a Honda NSF250R Moto3 bike, with custom triples clamps, wheel and brake spacers and adapters.

2-Stroke Honda Grom

  • Takagawa Swingarm
  • JRi rear shock
  • Woodcraft rearsets
  • Endurance ready dry-break fuel tank
  • Brembo 15RCS master cylinder
  • Ohlins steering damper
  • Tyga stainless pipe and silencer
  • Custom wiring harness and lighting system.

Honda Grom 2-Stroke

How do you classify this bike?

Hard to put this bike into a class. I think it’s in a class of its own.

Honda Grom 2-Stroke

Was there anything done during this build that you are particularly proud of?

I think I’m most proud that the bike is so fun and easy to ride and the balance has been maintained. It cruises along like any other bike, and will rip your arms off when you open the throttle.

Honda Grom 2-Stroke

Builder Thanks

Follow Jesse Davis on Instagram:  @xthirtysevenx

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