Top 6 Bikes to Turn into Street Legal Supermotos

So you want to convert your enduro into a street legal supermoto?

If you take the time to choose the right bike to turn into a supermoto, you will have a much easier time.

Not only do you need to consider the power behind the bike, but also the wheels, tires and suspension work as well. Then, you will need to think about the speedometer, horn, lights and wiring. Even the simplest wiring looms can become pretty complicated if you don’t know what you are doing.

You could easily end up with a bike that has more wrong with it than it does right.

The truth is, you can turn most any Yamaha, Suzuki or other bike into a Supermoto, but do you really want to? Check out our picks for the Top 6 Bikes to Turn into Street Legal Supermotos to see if your choice makes the cut. We’ll also cover the parts needed to make your dirt bike a street legal supermoto at the end including getting a license plate for your dirt bike.

Top 6 Bikes to Turn into Street Legal Supermotos

First… What is a Supermoto?

Generally speaking, a supermoto is known as a dual-sport or dirt bike with 17-inch rims. Typically, you would run a standard 3.5 front and up to 5-inches in the rear. Supermoto as a racing style is a cross between a motocrosser, dirt track bike and road racing single.

A dirt bike featuring street tires is commonly called a sportsman setup and is closer to being a supermoto bike. There’s more work to do than simply changing out the tires, but the biggest asset you have is the bike you choose for the conversion. You can make things much easier on yourself by doing a little research in the beginning.

Without further ado, our Top 6 Bikes to Turn into Supermotos.

1. Suzuki DRZ400

The DRZ is a fabulous bike for trails, but don’t underestimate the platform for your next street legal or supermoto conversion. This bike features an electric start and remains stable at highway speeds. It’s also plenty strong enough to handle the punishment an amateur would throw at it on a motocross track.

Yes, the Suzuki DRZ400 is heavier than the RMZ or CRF, but it is still plenty of fun on the track. To make it better, you’ll need to put the bike on a diet. Start by losing the steel tank. Then, take off the exhaust and carb and get an FCR setup instead.  You will also want to bypass the side stand switch. This will keep the bike from cutting out on jumps.

The DRZ400 has a lot going for it as a supermoto. There’s plenty of torque coming out of the 398cc liquid-cooled engine. It also features an instrument cluster and adjustable suspension. With a little work, you can carve out the corners of the world and deliver unprecedented performance on the street as well.

It’s the ideal combination of crisp handling and lightweight agility that make this one of the most popular supermoto dirt bikes of all time.

You can check out this guy’s conversion of his Suzuki DRZ400e model.

2. Honda CRF450X

The CRF450X can have many feels depending on where you ride it. It’s a versatile bike even with stock equipment. There’s a wide gap between second and third on this bike, but it delivers smooth and torquey pull throughout.

Honda based their CRF450X on the CRF250L Dual-Sport bike. Once you get on the back of this, you won’t care about that bike anymore. This is far superior and what dreams are made of.

To convert this beast to a street legal supermoto, you’ll need to make some minor upgrades. Consider all the standard components such as the wheels, tires, turn signals, lights, digital speedometer, license plate bracket, hand guards plus a new front fender.

You would also do well to install a larger front brake and radially mounted calipers for better stopping power. The original setup is strictly meant for dirt and just won’t do for the streets.

Here is a great video showing one guy’s converted CRF450X you will want to check out. His only trouble is figuring out how to do wheelies. Maybe he should read our other article on that.

3. Yamaha WR450F

The WR450F was completely reinvented from a somber trail bike into a race-oriented beast that likes fast riders. Yamaha included many components that make this an ideal conversion bike.

The Yamaha WR450F is our top choice for turning into a street legal supermoto.

Yamaha started with a YZ250F frame. They needed shoehorn the YZ450F engine inside, but they performed enough fabrication to make it happen. The extruded and forged frame adds some additional emphasis on horizontal and torsional rigidity.

This Yamaha features electronic fuel injection - the same 44mm 12-port Keihin system as the YZ450F. In total, five sensors are monitoring running conditions from intake air pressure, lean angle, throttle position, water temperature and air temperature.

This bike also features a Kayaba SSS suspension. Sure, this is more expensive but well worth the cost. The damping force is controlled by the speed of the fork instead of the damper rod position. This provides a more linear damping curve. The WR450F doesn’t share the YZ450F spring or valving specs. This means the WR has a softer setup.

All in all, it provides a smooth power delivery, consistent throttle response and unwavering performance.

You can get a closer look at what a modified WR450F looks and rides like with this YouTube video.

4. Yamaha YZ426F

The WR450F couldn’t be our only Yamaha supermoto because the YZ426F is just as capable of being a great street legal supermoto.

This model has been around since 1999, but even longer than that as the YZ400. You have to give Yamaha some credit for being the first Japanese manufacturer with a revvy, small four-stroke. That’s why the 426 continues to be a top seller today.

They are as quick as a 250 stroker but offer fewer gear changes, less maintenance and they operate great in mud. To get it supermoto ready, you will want to swap out some pretty common parts. The fender, handguards, wheels, rotors, sprockets, chain and brake line should all be revamped.

If you want the best of both worlds, you can easily set up this bike for a quick swap. Just keep the knobby and a complete oversized front brake assembly from the caliper to lever. Then, you can easily swap out the street equipment when you want to head out on the trail. You won’t even need to bleed the line. Just unbolt a caliper, lever and hose and put the other one on. Pretty simple!

Enjoy some YZ426F supermoto wheelies on Youtube.

5. KTM 450 SX-F

With 63 horsepower, this KTM is one of the fastest 450ccs that the company ever built. Aside from being perfect for motocross, the KTM 450 SX-F isn’t that difficult to turn it into a street legal supermoto beast.

We would start with a wheel kit, 44-tooth sprocket, new tires, updated front fender, new chain and 320mm rotor.

Aside from that, you’ll want to consider some new plastics, a dashboard computer kit, a light kit that includes your wiring harness, multifunction switch, blinkers and tail light plus a headlight. You could also add in a lightweight lithium battery and new bump seat.

You end up with the above: one of the best looking supermotos money can buy.

The trouble with converting this bike is the price. Brand new this bike cost almost $10,000, so it certainly isn’t in everyone’s budget to own one. With that said, we recommend it if you have the cash. You won’t have as much fun or draw as much of a crowd with any of the other bikes in our supermoto conversion list.

This bike sure has an impressive on and off-road demeanor. There’s no question you will stand out in a crowd with this investment.

Just check out the amazing work this guy did on YouTube. Inspiring, isn’t it?

6. Husqvarna FC350

There’s no question that the Husqvarna FC350 offers a superior balance of handling and power. That’s why it’s one of the best dirt bikes to turn into a supermoto. It features the agility of a 250 but offers the power-to-weight ratio of a 450. That’s why it’s been a favorite with amateur and professional riders alike.

It doesn’t really matter what condition you choose to ride in; the FC350 is a lot of fun.

It’s versatile and comes with launch control and intelligent traction control. On top of that, the lightweight motor cranks out 58 hp to make performance a priority. This is a must-have when you want to convert the bike to a street legal demon. Despite all the power, it is one of the lightest engines in its class.

The FC350 also comes with an updated cylinder head casting process. This further saves weight while the polished camshafts and DLC coated finger followers allow minimal friction. These aspects combined will enable you to rev the engine freely to 13,400 RPM.

Not to mention, it has the Husky name. That’s worth massive points on the ‘Gram and on the streets.

Take a closer look at this bike on YouTube and you will quickly see why it is a winner for a supermoto conversion and an incredible racer to boot.

How to Convert a Dirt Bike to a Street Legal Supermoto

If you want to convert a dirt bike to a street legal supermoto, you need to give careful consideration to what parts you choose. Yes, the right dirt bike is essential to an easy process, but the components are just as vital.

If you’ve ever taken a dirt bike out on the road, you know how much fun it can be to pull that front wheel off the asphalt. With that said, you can’t legally just take any dirt bike on the road; you must follow the rules of engagement just like anything else.

We’ll offer some of our best tips to get your bike ready for supermoto, but don’t forget to chime in with some of your pointers as well in the comments below.

Forged wheels

The first step to converting any dirt bike to supermoto is the changing out the wheels. The most common choice is 17-inch wheels for the front and rear. It’s far better than trying to ride with the stock 21/19 on your full-size dirt bike.

With a pair of 17-inch wheels, you lower your bike. This causes it to handle better, plus a wider tire helps you to lay down more rubber giving you way more grip. A front supermoto wheel usually contains a 3.5-inch width. In the rear, you will want to choose something between four and five inches.

Of course, you will have to see what works best for your bike setup. You can always go narrower or wider than what’s recommended, but that could lead to trouble. If the wheel is too wide, it might rub the swing-arm or chain. Too narrow and you’ll reach the end too quickly.

Of all the modifications you are going to make, the tire size is one of the most important, so take your time. If the rear tire is too wide, it’s going to hinder your performance. If the rear wheel width is too big, it could pinch the bead of your tire. This creates an extreme profile and a smaller radius which ultimately means you have less road surface.

By putting the correct tire on the wheel, you end up with more contact with the road. This allows you to perform better, so make sure you do your research before making a decision.

Spoked wheels

While we are discussing wheels for your dirt bike, let’s talk about retrofitting street bike wheels. It’s possible for people with machining ability to use some street bike wheels in order to save some money.

You will have to do some machining in order to produce the clearance needed to fit on the forks and swing-arm. The bearings themselves aren’t difficult to swap out, but you need to find wheels that use the same size bearings to fit your axle. If not, you will need to buy new bearings that have the correct outer and inner diameters.

Another concern with this method is mounting the caliper. You might be able to put the stock caliper on your wheels depending on the size rotor you choose or you might not. There are so many varying combinations of wheels and bikes which is why this isn’t a recommended course of action, though we understand why some people want to do it.

If it’s the path you choose, you will have to perform your own research. You need to have a deep sense of mechanical knowledge and the tools required to get the job done right. Just remember that cast wheels don’t feature as much strength as the spoked supermoto wheels do. They won’t withstand the same abuse of off-road riding and jumping like you might hope for.

Lights

Ever ridden behind someone you can barely see? Have you ever DRIVEN behind someone you can barely see? That’s a problem.

If you plan to ride on the road, then you must have the proper light setup. Each state has different requirements, but the typical rule is to have a headlight featuring a high- and low-beam, taillight, turn signals, brake light, reflectors and a mirror. Of course, some states still allow hand signals.

Thankfully, headlights aren’t hard to install. Just read the instructions and do what it says. If you are using a motocross bike for your conversion, you might need another power supply.

Charging system

A rewound or upgraded stator is the easiest path because it can power your lights alone. You just need to get a regulator so you don’t burn out the lights.

There is not an aftermarket stator made for every dirt bike. That’s why some people consider battery power alone for their street legal conversion. It’s simple to find the right aftermarket system for most dirt bikes and many are powered by batteries that are simple to swap. You can expect several hours of power before you have to change them.

The other option you have is a rechargeable lithium LiPo battery system. These are the same type used in RC cars and models. To match your lighting system, you will want a four-cell 12-volt setup. While it might cost you more up-front to do it this way, recharging the batteries is simple and painless. Then, you don’t have to worry about carrying around a bunch of batteries when you want to take a ride.

Brakes

Once you give your bike the power it needs to go faster, you need to consider stopping just as fast. Converting your dirt bike to be street legal also means you should upgrade that front brake. The rear brake isn’t as important because it doesn’t handle the majority of the braking. The only time that it would be necessary is if you plan to compete in supermoto competitions or do excessive stunting.

Modifying the brake system is straightforward. You have the rotor, caliper, brake line and master cylinder to consider. Start by replacing your brake rotor with something larger that offers more leverage. Many motards prefer to use a 320mm rotor.

You can typically use the stock caliper with your larger rotor, but the location isn’t going to work. You must often purchase a relocation bracket to accommodate the rotor. This is where you need to be careful. Getting the right bracket can be difficult. A common upgrade is to replace the caliper with a four or six-piston design because it produces the maximum stopping power.

It doesn’t cost a lot of money to upgrade the brake line to a braided design made from aluminum or steel. These perform far better than those stock rubber hoses and are well worth the money. Not only that, but it will hold up to more pressure and allow you a more consistent feel in comparison to the stock version.

If you want to upgrade the master cylinder, you have to know this can be expensive. But if you need maximum stopping power but don’t want to put out more finger effort, then the upgraded master cylinder does the job. You have many options out there, but you will get what you pay for. You can also take a master cylinder off a different street bike you might have lying around. Just do your research to check compatibility.

Accessories

Once you start building your supermoto, you’ll find it becomes an addiction. Once you are finally done, you’ll realize you probably put more money into it than you planned. That’s exactly why it costs so much to buy a used street legal supermoto already built.

You can also purchase a complete conversion kit for a dirt bike which makes the transition a little smoother. The other benefit to this is that you can always go back to your stock setup if you decide dirt riding is better for you.

Aside from the other aspects we’ve talked about, you might also want to consider adding some street gearing and sprockets. It’s also wise to consider upgrading the foot pegs, exhaust and other accessories you might not immediately think about. If you plan to carry any passengers, you will also need to upgrade your passenger seat for their comfort.

Or don’t. That’s between you and the other person’s butt.

Making a Dirt Bike Street Legal

There’s no question that you need a lot of components to make most dirt bikes street legal. Each state is different as to what is required, so you need to do your homework. Even still, some basics are almost always needed to pass inspection.

For example, most every state requires that your bike has a working horn. At first, you might wonder what type of horn you need, but the reality is you don’t need something fancy. Just head over to Wal-mart and grab yourself a cheap horn. In most cases a bicycle horn will pass inspection, but it won’t save you in an accident.

Some states also don’t require turn signals, but still allow riders to use their hands. If this is true for you, then you can save yourself some money.

Your local laws may require more, but your dirt bike turned street legal supermoto will need at least:

  • Headlights

  • Tail light with brake light

  • Mirror

  • Horn

  • Street legal exhaust

  • Street legal tires

Most of these parts are standard on today’s most popular models. Especially if you have a factory-built street legal dirt bike you probably have most of those already, but if not you can probably install them in a weekend.

You will likely need a hi-low beam headlight, brake light, tail light and reflectors. Even if the reflectors aren’t required, we have to recommend them. It makes it much easier for others to see you and the police are less likely to pull you over when you have this safety equipment installed. If a mirror is required for legality, then grab yourself a simple bar-end or handlebar-mounted mirror.

Furthermore, you will need a road-legal exhaust system and tires to pass inspection. The majority of dirt bikes have an exhaust and tires that clearly say, “for off-road use only” right on them. That doesn’t work.

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You Also Need a License Plate

Your first step is getting the right supermoto. Your second step is modifying it to suit your neeeds. And whether you buy one new or build it yourself, your third step is driving it on the road legally.

That’s where Dirt Legal comes in. Making things street legal is what we do. You’ll just need to call us at 800-994-7513 or email us at info@dirtlegal.com. Or visit our Dirt Bike Conversions page by clicking the link.

From there, we’ll send you some documents to fill out. Then we’ll work with the DMV to ensure that all laws are followed in making your dirt bike street legal to drive on public roads. You’ll get a license plate, title, and registration!

No hoops and no hidden clauses – just you, your supermoto, and the open road.

We even sell all the horns, blinkers, and parts you need to convert your own vehicle. We can handle all the DMV paperwork to get you a license plate and registration without you even having to leave your sofa.

Enjoy the ride!

It’s possible to take almost any bike and turn it into a supermoto; the question is how much effort you want to put into it. With one of the six bikes to turn into street legal supermotos we listed here, you have the best chance of an easier transition.

No matter what bike you choose, convert it proudly and enjoy the open road.

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