The Honda CRF50 is one of the most popular dirt bikes in the world. It all started in the 1960s with the Honda Mini-Trail 50. Over the years it has transformed many times as the QA50, Z50, XR50 and currently into the CRF50. You won’t find a more dedicated bunch of owners and racers than the Honda 50 crowd. BBR has been there from the start; from the backyard races around the world, to MiniMoto SX. Our staff and race team is passionate about the Honda 50s and are excited to share our products and knowledge with you. The must-have items to get you started on the 50 are: a Handlebar kit, exhaust system, tall seat, chain guide, springs and 88cc kit. From bar kits to the championship winning perimeter frame kits, BBR has you covered.

This page has some popular links to help you navigate our website for information on the Honda CRF50F (XR50) and help you find what you are looking for. If you have any questions, please feel free to contact us via e-mail or give us a quick phone call. Our staff is ready and waiting to help you make the most of your motorcycle.

OEM Honda CRF50F (XR50) Specs

Displacement 49cc
Bore and Stroke 39.0mm x 41.4mm
Compression Ratio 10.0:1
Spark Plug NGK CR6HSA
Valve Clearance IN: .002" EX: .002"
Carb/main jet/pilot jet 13mm Keihin / 58 main / NA
Transmission ratios 3.272 / 1.667 / 1.190
Oil Capacity/Type 0.8 US Quarts / 10W-30
Chain size/front sprocket/rear sprocket       #420 chain; 14T/37T
Front tire size 2.50-10
Rear tire size 2.50-10
Seat height 21.6 in.
Wheel Base 36 inches
Weight 110 lbs.

CRF/XR50 Frequently Asked Questions


Is the BBR pipe louder than stock?

Yes.Power and sound go hand-in-hand. Great for riders (but not so good for neighbors). If you're looking for a quieter ride, We have designed the BBR CRF/XR50 pipe to accept the stock endcap from the CRF/XR50 exhaust. This lets you achieve the same noise level as stock. When you are riding in your backyard, you pop on the stock endcap (3 bolts). When you're at the track, trying to beat the local heroes, you pop on the BBR endcap. Or you can order the BBR quiet core and run the fluted end cap.

What is the difference between BBR's pipe and the other guy's pipes?

It's all in the details. Over the years we've raced and won practically every major mini 4-stroke race in the country and we sell the same pipes we race with to the public. Our designs are painstakingly developed to achieve the best possible performance. Most models use multi-stepped headers and all our headers are ceramic coated or stainless steel. The muffler can is anodized to protect it and keep it looking great for a long time. Because we're concerned with noise restrictions, many of our exhaust systems will fit the OEM endcap (for stock noise level). For full race mode, we include our super trick billet aluminum endcap and US Forest Service approved spark arrester. We regularly test our competitors pipes and are confident that ours are the best exhaust systems made. We have the results to back up our testing.

How fast will the CRF/XR50 (or BBR XR50) go?

Not very fast. That's why it's so fun to ride. We do not measure top MPH of any motorcycles. In motocross, it isn't how fast it goes, but how quickly you get there.

Can BBR sell me cables so that I can use one of the other available triple clamps?

Yes! We are selling our cables and accessories as a kit. Check out our CRF/XR50 product pages for more details.

Why does BBR always use aluminum for its frames?

When used correctly, aluminum is the strongest, lightest material available for use in motorcycle frame construction. Few companies use it because of the difficulty in machining, welding, and heat-treating. The BBR crew has worked closely with major motorcycle manufacturers perfecting the art of frame building

What fork does BBR recommend for the CRF/XR50s?

The SP-5 forks are a great all-around fork for the CRF/XR50. The damping and spring rates are designed for adult riders and hold up well for most abuse. They are the best forks available for backyard play riding and the best bang for your buck. If you're going big and for the ultimate performance and durability we recommend the BBR E-6 or Marzocchi Shiver Works fork kit. We don't sell them anymore

Does BBR sell a disc brake setup for the CRF/XR50?

Sure. Check it out on our products pages.

Can you help me jet my XR50?

Jetting is highly dependent on the climate. The quickest jetting test is to play with the choke. If your bike has an off-idle stumble, that gets better by pulling the choke on slightly, then you know that the bike is to lean. The quick fix is to move the clip on the needle down, or go up 5 sizes on the main jet. This is usually the case with any aftermarket pipe (BBR included). You are flowing more air which means you need more gas. The stock CRF/XR50 main jet is a 58. Other sizes are available from BBR or your Honda dealer.

Is the XR50 legal to race in the 2-stroke 50 class?

Every track and racing organization is different. Our local tracks run a separate class for the CRF/XR50 (it happens to be the biggest class). Check with your track officials.

Are the BBR CRF/XR50 springs too stiff for my younger kids?

These were designed with adults in mind, but we have lots of fast kids that absolutely love them. You'll have to make the decision. They are about 60% stiffer than the stock springs.

Does BBR make a big-bore kit for the CRF/XR50?

Yes. BBR currently sells two different big bore kits. The 88cc kit with a cam, and the 88cc Flat top piston Bore kit. One for the stock valve head and one for the big valve head. These kits are our own aluminum cylinder with iron liner, 88cc piston, rings, pin, clips, gaskets, and a high performance camshaft. No exchanges are required. This piston is 9.75:1 compression (with the CRF/XR50 head) and will run great on pump gas. We prefer this setup over the bigger bore kits as it lasts longer, is easier on the oil, and doesn't overheat as easily. This due to the thicker cylinder sleeve. This kit is the quickest way to double the horsepower on the CRF/XR50 without reducing reliability. If you're going big, trying to make money, or just need to have the coolest bike in your neighborhood garage, the Kitaco 124SE kit or Daytona 4-valve kit is the way to go. Engine kits for the XR/CRF50 change daily. So feel free to give one of our expert sales techs a call for all the latest info.