MOTOCROSS ACTION MID-WEEK REPORT
Rider: Ryan Villopoto
Bike: Factory Kawasaki KX450F
TWO-STROKE SPOTLIGHT: HOGAN HAEBER’S HONDA CR500AF
“I’ve wanted to build a CR500AF since I was probably 16 years old. I finally had the chance when I was 20, so I bought a 2006 rolling chassis from a buddy with the intention of someday building a 500AF. Tore it down to the frame and waited patiently until I found the right CR500 power plant. Finally found a good 2000 CR500 great running bike. Pulled the engine and began the swap.
Piecing the engine together.
I ordered a CR500 conversion kit and got started. I cut the “Y” piece, got the engine bolted in with the swingarm bolt, got the head stay mounts all together, mocked up the new Billet Y piece and began trimming the rest of the frame to fit. The engine fit and I liked the placement. I did the necessary, but simple exhaust mods. Fitted the aftermarket over sized radiators (which was probably my biggest challenge)m finished the air box mod, and assembled the bike again with a ton of aftermarket and performance goodies. It was an incredibly fun and challenging build. I’d love to build another in the near future.”– Hogan Haeber from Roseburg, Oregon
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 protected]. 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. Please don’t email me spam or try selling me Taylor Swift concert tickets or email me spam. Happy submitting your smoker.
Name the rider. Answer at bottom of page.
PRO CIRCUIT ENGINE PLUG KITS
Press Release: At Pro Circuit, we are committed to providing our customers with high-quality accessories that are more durable than OEM and give your bike a factory look as well. This is why we’re excited to release our new Engine Plug Kit for the 2014-2020 YZ250F and 2010-2020 YZ450F models. Machined from aircraft-grade aluminum, hand polished and anodized blue, these new plugs are a must-have for any rider looking to add a little flash to their YZF. Give your bike an upgrade with Pro Circuit accessories.
WILL MOTOCROSS BIKES SWITCH TO CARBON FRAMES IN THE FUTURE?
Bicycles once came with steel frames, then aluminum and now carbon fiber. And Formula 1 used to have steel frames, then aluminum monocoques and now carbon fiber tubes. It seems obvious to me that motocross bikes will soon be switching to carbon fiber also. Am I right?
It depends on how much you hanker for a $20,000 production bike. As exciting as exotic materials may look on the sales brochure, motocross chassis are about feel, not materials. One of the reasons that KTM has made so much progress against the Japanese brands has to be attributed to the chromoly steel frame. Chromoly steel offers both tensile strength and the ability to flex in the right direction. It’s the flex of a steel frame that makes a KTM a very good all-around handling machine. Steel may seem old fashioned, but for motocross frames, it is really a very high-tech solution. And, if you had the wherewithal to build a one-off race bike, steel would be the place to start. The Japanese factory teams cannot race with steel frames without making their production bikes look suspect. Don’t forget, Jeremy McGrath left Team Honda over this exact issue back in 1997.
Don’t get too misty about aluminum frames. They have endured a very rocky history to get where they are today, largely because aluminum does not flex and, if it does, it tends to crack its large-grain composition. Starting with the original 1997 Honda Delta Box frame, aluminum produced frames so stiff that they lost feel and placed 100 percent of the suspension burden on the forks and shock. Over the last 18 years, the Japanese manufacturers have been tapering the aluminum extrusions, thinning the wall thicknesses and relying on the motor mounts and head stays to soften up the feel.
Aluminum, much like air forks, became the cause celebre in the factory accounting departments because it was cheaper to manufacture and didn’t require any cutting, bending, mitering or gussetting. An aluminum frame is made up of eight cast, extruded or forged parts that plug together.
There are companies experimenting with molded carbon fiber frames. These builders tout carbon fiber’s light weight and controllable stiffness. But, in a production frame, no manufacturer would take full advantage of carbon fiber’s light weight for fear of a frame failure. Thus, they would lay the carbon fiber up well beyond the fail-safe level, and that would result in not only a heavier frame, but a stiffer one. Yes, it is possible to lay the carbon sheets up to get more flex, but with a risk level that the corporate lawyers would never sign off on. Think about carbon fiber handlebars. They first surfaced on mountain bikes back in 1986, but when racer Aaron Cox’s carbon bars broke at a Big Bear race the same year, carbon fiber bars suffered a setback that they have never recovered from. The same risk applies to motorcycle frames, which do break, regardless of what they are made from, but a broken carbon fiber frame would be a death knell to carbon fiber’s future in motocross.
Plus, motocross is not held on a pool-table-smooth F1 track or on a mildly bumpy Tour de France road. It is a gritty sport complete with shotgun blasts of roost, hard crashes and mechanically inept owners. A scratch could lead to carbon fiber failure. Spraying the wrong chemical on the carbon fiber could delaminate the cloth. The abrasion of a boot can eat through the welds on an aluminum frame; imagine what it would do to carbon fiber.
Carbon fiber may well be the brave new world of chassis design in boats, planes, bicycles and race cars, but the high cost of production and high premiums for liability insurance pretty well nix it for anything more exotic than skid plates, subframes and mufflers in motocross.
THE MXA WRECKING CREW TAKES OVER MIKE ALESSI’S BLENDZALL YZ134 & ESR YZ325
This engine is built of parts from around the world. Mike’s dad, Tony Alessi, who is also the team manager of the Moto Concepts Supercross team, is a guy who knows a thing or two about building great race machines.
Have you seen a tiddler push around that much dirt before? We aren’t going to give you the juicy details of Mike’s YZ134 until it hits the magazine. Let’s just say this puts Ryan Villoptoto’s YZ125 to shame.
LOST BUT NOT FORGOTTEN | 1992 SUZUKI RM125
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MXA’S TM 144MX PROJECT BIKE
INSIDE RYAN HUGHES’ SPILTFIRE PRO CIRCUIT KX125 FROM 1994
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MXA Trivia answer: Eric Sorby