This is for the Honda CR500 enthusiast…
It’s well known that any person that possesses a CR500 in his garage loves one thing, HORSEPOWER! There are many other bikes to choose from, most of which play a much gentler game then the CR500. The fact that he chooses this beast clearly says, I love untapped eye watering potential. Is that you?
Gone are the days where steel framed CR500’s were the dominant breed, and aluminum frame conversions were the unicorn. Over the last 20 years this script has been flipped, with AF conversions now leading the charge. It was important to us that the pipe covers as many bases as possible. To fit steel framed bikes (from 1989 and up), as well as accommodate AF conversions as much as possible.
With the popularity of the CR500 in high HP environments such as snow biking, supermoto and hill climbs, the pipe needs to excel with modified engines. The stock CR500 has brutish low-end power, and a softer top-end. This is largely due to the port arrangement, and low port timing of the stock cylinder. On typical CR500 modified engines, it is commonplace to open the ports as well as raise the port timing. The key? To make a pipe that excels with stock engines AND mod engines. We set out to outdo the competition and build the ultimate CR500 pipe.
For our baseline we dyno’d a stock ‘98 CR500, coupled with a FMF Fatty pipe. Why the Fatty? It is probably the most readily available CR500 pipe and provides good useable overall power. Our goal? To match the frontside power delivery, but add midrange and peak power. We also aimed to go one step further, to expand the potential for modified engines. Leaving room to GROW.
DIALING IT IN
Both pipes were run until the jetting was dialed, and the pipes produced their best curves. Both ended up with a 172 main. With the jetting where it should be, both were run with the same starting engine, and pipe temp. NO other alterations were made between tests, other then swapping the pipe.
Looking at our dyno results, I know we have achieved our goals. Frontside power tracks the competition nicely, with the HYGGE leading the charge from 5,500-6,950 RPM by a large margin. Peak power is up an incredible 3.3 hp. Overrev is good and strong, and only falls below the curve for 500 RPM, before surging back to take the lead again. This time by a 10hp margin.
Some of you may be asking, why the dip in power at 6,950 RPM? Due to the design of our pipe and the low port timing of the stock cylinder, the pipe simply falls out of resonance in this range. In other words, the stock porting cannot keep up to the demands of the pipe in this window. To design a pipe that rounds this curve and does not have this dip (on a stock engine), would go against our goals. Doing so would cut peak horsepower significantly, as well as reduce the efficiency of the pipe when paired with modified engines. Looking back at our initial goals we knew this would be the wrong move. While we can do our best have our cake and eat it too, sometimes there just isn’t the right flavor of frosting.
If you took the time to read through this whole blog, BRAVO! You are tough as hell and definitely fit into the Hygge crew.
Special thanks to Adam Millar of MRE racing for providing this mule bike. Thank you Adam!