Honda CR500 Aluminum Frame Dirt Bike Build: The All-American Custom 2-Stroke – RM Rider Exchange
It’s a Honda CR500 Aluminum Frame bike build. Yes, you read that right. We took an ‘88 CR500 2-stroke engine and fit it into an ‘07 CRF250F aluminum frame. Everyone has their own far out goals and projects, and this one was Kevin’s. Kevin works in our R&D department, so he has plenty of experience with fabrication and has grown up on a love of riding and all things motorcycles. His passion, combined with that experience, made his crazy goal a reality when the stars aligned and he and his brother, Eric, found both bikes and some time to work on them. It was 10 straight days of persistent work, but it paid off with a one-of-a-kind bike that we are elated to show off.
Fabrication and Customization
Considering Honda never made a 500 two stroke with an aluminum frame, this project required a decent amount of fab work and customization. First, Kevin and Eric had to get the engine to actually fit into the frame, and then there was the matter of pipes, head stays, air boots, and other custom parts to complete the vision.
The most critical thing here, however, was getting the motor into the aluminum frame. There is a lot of tweaking, shaping, and forming that makes up that process. The alignment of the header of the CR500 is quite different from the ‘07 frame, so they had to order a custom billet y-piece to allow the exhaust to fit through the frame. Kevin and his brother wanted to keep the dual exhaust look of the ‘07 CRF250R, so they had to build their own y-piece, cut the expansion chamber short, and line everything up to the original dual exhaust position. In a build like this, figuring out the exhaust is another critical challenge like fitting the motor into the frame. After those puzzles are solved, everything else can be figured out as you go along. Once everything was welded, they had to fabricate motor mounts and bushings, form the gas tank to get it to fit, and work on other small, tedious tasks that took up the bulk of their time. For example, every bushing and bearing had to be replaced for this bike build.
The carburetor setup took a little custom work, too. The stock CRF250R air boot didn’t line up with the CR500 motor, so Kevin and his brother had to make an adapter plate to go from the CRF250F air box and use a CR125 air boot that is a much closer match to the carburetor. It didn’t align perfectly with the carburetor, but it was good enough to get the job done.
When the fabrication and customization were complete, they wanted to throw some other parts and accessories on there to give the bike a modern feel and really take its performance to the next level.
The first thing added were some Fasst Flexx handlebars. The 500 vibrates a lot – it’s pretty much the first thing you notice when you start it up – so we needed to get some bars to help mitigate those vibrations. The Fasst bars are up to this task because they’re designed to isolate vibrations and impacts, thus dramatically reducing that feeling during your ride. Each bar end mounts on a free-moving hinged point, allowing for the bars to absorb those bumps and vibrations. Elastomer bumpers mounted underneath the pivot joints dampens the movement and controls the rebound, basically directing all of that vibration away from your arms. Working in tandem with the Fasst Impact Moto Pegs, the handlebars helped to alleviate the stress that vibration brings during a long ride.
Another thing Kevin and his brother noticed about this bike was that the braking was lacking, so they installed the Tusk Oversized Floating Typhoon Brake Rotor Kit. Oversized rotors increase performance and braking power, and this specific kit boasts tempered stainless steel construction that works with any type of brake pad. The floating design provides exceptional pad to rotor contact and even heat distribution, making braking reliable and smooth.
The bike was also outfitted with a Magura Hydraulic Clutch. We are a big fan of this clutch here at RMATVMC for the smooth and easy clutch pull it provides. Magura claims that up to 20% less force is required to pull their lever compared to a cable actuated clutch, and that’s something that you’ll feel after a long day of riding. The pull is predictable and consistent, making it great for technical terrain or just those all-day adventures. For those reasons, this addition was actually one of Kevin’s must-haves for the CR500 specifically. The old engine has so much resistance that this clutch makes it much more manageable and easier to ride for longer durations.
After the rideability of the bike was addressed, Kevin and his brother added several parts to enhance the performance of the bike, including new tires, wheels, drive components, silencers, and a larger gas tank.
The CR500 Aluminum Frame is an awesome bike for the dunes, which means dune tires. For tires, the duo opted for the Tusk EMEX T-35 tires on the front and the CST Surge C7220s on the rear. One of the newest tires from Tusk, the EMEX T-35s are designed to provide traction, reliability, and stability while easily transitioning from softer to harder surfaces. With eight paddles, the CST tire provides decent traction in the sand and is fairly cheap for how well it performs and resists chunking.
With the tires mounted on the Tusk Impact Wheels, the kit really came together. The Impact wheels are available in various rim, spoke, and hub packages, making it a customizable piece that can contribute to the overall look of the bike. More than that, however, the wheels are made from high-quality materials that can stand up to the ride. As an extra bonus, the wheels all arrive pre-assembled.
Primary Drive took care of the drive components on the bike. The Gold X-Ring Chain, paired with front and rear sprockets, provided the strength and durability the brothers were after.
The new silencers were some of the most exciting parts to get installed. Kevin and his brother spent a lot of time configuring the bike to allow for dual exhausts, and all of that effort paid off when they installed the FMF Power Core II Silencers. FMF’s pipes have a well-deserved reputation for being both high quality and high performing. They fit perfectly into the vision the brothers had for the look and sound of the bike.
You can’t ride all day without a larger gas tank, and that’s something the brothers considered early on in their build. They were able to fit the Acerbis 2.9 Gallon tank in their bike, a great addition that will give them extra range for the many rides to come. This tank is one of the most popular aftermarket options we have at RMATVMC, a testament to its reliability and durability.
Completing the Look
With all of the essential and performance parts nailed down, Kevin and his brother still had room for a few extra parts. The bike understandably needed a new plastic kit, so on their new Acerbis Replica Plastic Kit, the brothers installed a custom graphics kit from Attack Graphics. The personalized graphics brought the look of the bike home, rounding out every other part and accessory the duo had installed to make the bike one cohesive and cool-looking machine. The final bike was affectionately nicknamed “Project Whiskey” in tribute to the cult classic film “Hot Rod.”
The Final Product
When it comes to projects like this one, the lingering question is always cost. If you’re thinking about taking something like this on, here’s the breakdown. Buying the bikes was the first expense – Kevin and Eric were able to get their hands on a CRF250R with a blown motor for $800. They turned around and sold the parts they didn’t need, bringing the real cost of the bike down to $400. The CR500 was acquired for $2,500, and then it was another $3,500 in parts and custom upgrades to revive and improve the old 250 chassis. This brough the total build cost to close to $7,000 which, when you think about it, isn’t too bad for turning two bikes into one wild, like-new bike. That said, this project was still an investment. Kevin and his brother had the experience, time, and resources to complete this dream build they’d been envisioning for a long time. If you have a similar build you’ve wished you could complete, start doing your research now. There’s no better time to start than now, and there’s no better feeling than ripping that custom bike and showing it off.
Tell Us What You Think
What do you think about this build? Would you take this bike for a ride in the dunes? Let us know in the comments below.