“I completely restored this 1979 Yamaha YZ125. Everything done. Buchanans did the wheels and Matt Crown Racing rebuilt the monoshock. All sandblasted and powder-coated. DC Plastics for the plates. Race Tech did the forks and Dave Bowman did the engine and was a huge help with great advice.” –Bob Patchett
EDITORS NOTE: Please keep those submissions coming. If you would like your bike to be featured in the “Two-Stroke Spotlight,” please email me at email@example.com. All I ask is that you give a breakdown of your bike and a detailed description of the build. Please also send a few photos of your steed. By submitting your bike for the “Two-Stroke Spotlight,” you agree to release all ownership rights to the images and copy to MXA.
HONDA RELEASES 2022 GREEN STICKER MODELS
Press Release: Honda continues to offer a number of dirt bike models that meet the California Air Resources Board’s new emissions standards for 2022 model-year and later off-highway vehicles. CARB’s updated rules eliminate new Red Sticker vehicle sales for model year 2022 and onward. Model-year 2022 and later off-highway vehicles that are not Green Sticker compliant will not be allowed to operate in California SVRAs.
Announced last March, the 2022 CRF450X continues to be eligible for a Green Sticker and may be legally ridden year-round at SVRAs. Suitable for trail riding, this popular model performs at such a high level that it is also capable in competition, having amassed 14 victories in the Baja 1000, including the last six editions.
In addition, the entire CRF Trail family—the CRF50F, CRF110F, CRF125F and CRF250F—remains Green Sticker compliant. The road-legal CRF450RL may also be legally used in California SVRAs.
“With CARB’s changing regulations, we’ve heard from a number of customers who are concerned about being able to ride their dirt bikes in California public riding areas, but many Honda models are already Green Sticker compliant,” said Brandon Wilson, Manager of Sports & Experiential at American Honda. “We’ve moved our off-road line in this direction over the past several years, enabling us to offer one of the powersports industry’s more substantial lineups of Green Sticker-compliant models. Equipping off-highway vehicles with the necessary clean-running technology isn’t always easy, but doing so is an important way of protecting the environment and keeping public riding areas beautiful.”
Honda’s lineup of Green Sticker-compliant powersports products isn’t limited to two-wheel models, as many Honda ATVs and side-by-sides can also be used year-round in California’s public off-road areas.
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NIHILO KTM/HUSKY/GASGAS 85SX CHAIN ADJUSTER KTM 20mm AXLE
MXA TESTED | 2022 KTM 250SXF
MXA | MOTO | TRIVIA
A FEW HEAVY HITTERS AT GLEN HELEN LAST THURSDAY | photos by Trevor Nelson
TAKE THE MXA SURVEY FOR A CHANCE TO WIN A SUNDAY MOTORS FLAT TRACKER
Don’t pass on this opportunity to win a free Sunday Motors bike! Completely fill out the annual “Reader Survey” below or click here. We’ll take your input to help improve both the web and monthly print content of Motocross Action. One lucky winner will be chosen at random to receive a bike from Sunday Motors. For a few minutes of your time, you’ll be entered into a drawing to win this Sunday Motors S 147 flat-track motorcycle. The S 147 model features a 150cc engine, Mikuni carburetor, 14-inch front/rear tire, stainless steel footpegs, bottom-mount brake caliper, YCF 310mm rear shock, 200mm rear disc, low-exhaust configuration system, and kill switch with leash. One winner will be chosen on July 6, 2021.
The MXA wrecking crew is busy year-round testing motorcycles and producing content for the magazine and website, but once a year we compile a “reader survey” to help us learn more about our loyal magazine/website readers and viewers. We take your input on the survey to help improve both the website and monthly print content coming from Motocross Action. This year, we are offering the super cool opportunity of winning a Sunday Motors 147 Flat Track motorcycle! Completely fill out the annual MXA Reader Survey by click here. One lucky winner will be chosen at random to receive a bike from Sunday Motors and you’ll be helping us out as we strive forward continuing to testing motorcycles, parts and gear. One winner will be chosen on July 6, 2021.
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THIS WEEK IN MXA | #26
2022 TM MODEL SNEAK PEEK
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WHAT DOES HORSEPOWER ACTUALLY MEASURE?
What does horsepower measure, and what does a horse have to do with it?
Every motorcycle racer wants a measurement that explains how powerful his bike is. Horsepower is an easy reference number that everyone can relate to. Perhaps in the future, scientists will come up with a more precise measurement of how fast a motorcycle engine is, but whether they choose kilowatts, cheval-vapeur or joules, it won’t matter if you can’t get the public to go along. Horsepower has a long tradition, and it will not go gentle into that good night. People won’t want to change from 50 horsepower to 37,285 watts.
We mention watts because horsepower as a measure of power was coined by James Watts, who wanted to market his industrial steam engines to replace horses in 1782. Watts determined that a horse could turn a standard 12-foot radius grain mill wheel 144 times in an hour (or 2.4 times per minute). He then extrapolated a horse’s effort to the performance of his steam engine to be able to rate it by “horse power.”
The ultimate calculation was that 1 horsepower was equal to 550 foot-pounds per second (or, in simpler terms, that a horse could raise 550 pounds of weight 1 foot in one second). These numbers could be converted easily to other units of measurement. Thus, one horsepower also equals 33,000 foot-pounds per second, 745 watts, 0.645 kilowatts or 745 joule per second.
The point isn’t about what unit of power we use but whether that unit can be used in science and industry as a reliable measurement of how powerful a machine is. It is a given that 1 horsepower equals 550 foot-pounds per second. The importance of the “per second” part of the equation is that it changes horsepower from a measurement to a calculation. The time factor means that you don’t actually measure horsepower, you measure the force exerted over a distance during the duration of a given time. The resulting number is called horsepower, but the force that is being measured is torque.
How do you apply all of this? Motorcycle tuners use a dynamometer to determine the power an engine produces. They do this by applying a load to the engine output shaft by means of a water brake, a generator, an eddy-current absorber or any other controllable device capable of absorbing power. The dynamometer control system causes the absorber to exactly match the amount of torque the engine is producing at that instant, then measures that torque and the rpm of the engine shaft. From those two measurements, it calculates observed power. What the dynamometer is really doing, however, is measuring the torque output of the engine. In a vehicle, torque is measured at various engine speeds, or revolutions per minute (rpm). These two numbers are fed into a formula—torque times rpm divided by 5252—to arrive at horsepower.
What is more important, torque or horsepower? Most motorcycle companies advertise the horsepower and torque that their engines produce. It seems, as usual, the bigger the numbers, the better. Torque is the base number for work, and horsepower is the rate of doing more work. Thus, one can’t exist, or even have meaning, without the other.
CLASSIC MXA PHOTO
Moto Trivia answer: The year was 2000 and number 32 on an FMF Honda CR125 is Danny Smith. Danny finishes 10th overall in the 125 National series that year.