Is the Honda Grom Street Legal?



The Honda Grom is generally street legal, but it depends on the “street” you’re talking about.

At 125 cc—or 123.9 technically—the Grom is classified differently in a lot of jurisdictions, sometimes a “scooter” or “motor-driven cycle” and sometimes a standard “motorcycle.” 

Regardless, you can ride the stock Grom on city streets just about anywhere.

It’s the highway where things can be more complicated. While 50cc is generally the lower limit for limited-access freeways in the US, some states increase this to 125cc or more, effectively banning the Grom.

Let’s dive into the various legalities of riding your Honda Grom in public.

Where Is the Honda Grom Highway Legal?

First of all, let me clarify that by “highway” here, we’re talking about limited-access motorways. These are the big highways where the directions are divided and you have to use on- and off-ramps to enter and exit.

The usual lower limit in the US for the highway is 50cc, by default allowing the Honda Grom. Nonetheless, some states make their own higher limits that exclude the Grom. They include:

  • California (150 cc)
  • Illinois (150 cc)
  • Michigan (125 cc)

This is far from an all-inclusive list. In some states, restrictions may only apply to dense areas or be handled by local authorities.

Usually, restrictions will be posted at highway entrance on-ramps specifying the minimum displacement required, or in some cases the minimum horsepower or speed. In any case, it’s worth checking with your local DMV to be sure.

Are Aftermarket Parts Street Legal?

There are a lot of factors that come into play when determining if your aftermarket parts are street legal. There are environmental and emissions laws, sound ordinances, and, of course, the different state regulations that all have to be considered.

The parts most commonly affected by laws and restrictions are exhausts and intakes because they affect both emissions and sound.

Other commonly affected parts include manifolds, camshafts, and electronics systems like fuel regulators. 

As for states, California is easily the most restrictive, with the California Air Resource Board, or CARB, handing out hefty fines for those breaking the rules on aftermarket parts.

Many aftermarket parts in California are only legal on motorcycles registered for racing and even then may only be used on isolated racetracks or off-road, not on public streets.

It’s not just California, though. If you’re looking to upgrade or modify your Honda Grom, make sure whatever parts you’re buying are street legal by federal law as well as in your state and local jurisdiction.

Do You Need a License?

Yes, you’ll need a motorcycle license just about everywhere to legally ride your Honda Grom on public streets. Still, the details of your state’s licensing requirements and restrictions are worth looking into. 

Read our in-depth guide to motorcycle licenses and the Grom.