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2007

HOW TO BUILD AN INEXPENSIVE TWO-STROKE THAT JUNIOR CAN RACE IN THREE CLASSES

At first glance, this machine might make you think that Honda is bringing back two-strokes for 2014, but that isn?t the case. Just looking at this bike, you would never guess that it is a seven-year-old Honda CR85 Expert. Or, that it was bought off of Craigslist for $700. MXA was interested in a cheap, well-used CR85 Big Wheel because we thought that it would be the perfect transition bike for a young rider making the step up from the minicycle class to the big bikes. Imagine Junior getting another year…

WE BUILD AN L.A. SLEEVE YAMAHA YZ270:

If you own a 2006 to 2010 Yamaha YZ250, consider yourself lucky. You have one of the best motocross bikes ever made. It weighs less than a comparable four-stroke, costs less to repair and produces more horsepower per cc. And most importantly, it comes stock with Kayaba SSS suspension. It is a sweet motocross machine. However, there is a but. If you are racing your YZ250 against 250cc four-strokes, you have a superior motocross machine; but if you race the 450 class on your YZ250, you are giving up a bun…

MXA PRODUCT TEST: DIRT TRICKS KTM CAM CHAIN TENSIONER:

WHAT IS IT? Dirt Tricks? automatic KTM cam chain tensioner uses oil pressure, combined with a mechanical ratchet system, to maintain constant pressure on the timing chain (and avoids the possibility of the cam tensioner collapsing during oil pressure fluctuations). WHAT’S IT COST? $69.95. CONTACT? www.dirttricks.com or (775) 267-6361. WHAT STANDS OUT? Here’s a list of things that stand out with the Dirt Tricks automatic cam chain tensioner.      (1) Oil pressure . The stock KTM …

THE BEST USED BIKES! WHICH 450’s TO KEEP FOR ANOTHER SEASON? Which Used Bikes To Save And Which Ones To Jettison; We Name Names

CAN MY OLD 450 MAKE IT ANOTHER SEASON OR TWO? THE MONEY YOU SAVE CAN FINANCE YOUR RACING CAREER    Let’s take it for granted that your trusty, but rusty, old bike isn’t leaking fluid out of the shock, making clunking noises at low rpm, suffering from terminal rust behind the ignition cover, cracking down the head tube like old concrete or oozing tranny oil that looks more like chocolate milk than 30 weight. If your bike is sound and air worthy, your next questions should be:  …

ASK THE MXPERTS: What Is The Best 2007 RM250 Jetting?

LOOKING FOR THE BEST 2007 SUZUKI RM250 BRASS Dear MXA,     Can you tell me your corrected jetting specs for the 2007 RM250 two-stroke?      After years of horrible RM250 jetting, Suzuki did a fairly good job with the 2007 model.     It was a little rich on top, but nothing that changing the stock 168 couldn?t fix. On warm day we ran a 165 or 162 main and dropped the needle by putting the clip in the second slot from the top. Send questions to mxa@hi-torque.com

DRD: New CRF Radiator Lowering Kits

Norco , CA. (May 29, 2007)  Dubach Racing Development (DRD), is proud to announce immediate availability for the new CRF Radiator Lowering Kits.   DRD delivers a factory-level modification that improves handling, is simple to install and retails for $49.95   Radiator Lowering Kits help to lower the center of gravity improving the CRF’s handling character, most notably, entering and exciting corners when the bike is laid over.   Best of all, this modification is easy enough for any ri…

MXA’S 2007 KAWASAKI KX250 RACE TEST

It is entirely possible that the 2007 Kawasaki KX250 is living on borrowed time. Last year, with little or no warning, Kawasaki dropped the KX125 from its lineup. The fact that the KX250 survived into 2007, albeit unchanged, is a testament to the hard-core loyalty of two-stroke fans. Kawasaki doesn’t want to abandon riders who are looking for a low-cost, easy-to-maintain, lightweight and snappy race machine. That list of attributes can only be applied to a two-stroke. By comparison, four-strokes are hig…

MXA BIKE TEST: 2007 YZ250

The truth about 250cc two-strokes is that they are wonderful pieces of racing machinerytechnically advanced, lightweight, blazing fast, cheap to maintain, and capable of being worked on with backyard tools. All of that is undeniableas is the fact that the modern motocross two-stroke can be found in the encyclopedia right next to the now-extinct dodo bird. Of the four Japanese manufacturers, Yamaha is in the catbird seat when it comes to two-strokes. They own the two-stroke market. When they introduced t…

2007 KAWASAKI KX250F INFORMATION

(press release) Kawasaki’s all-new four-stroke KX?250F rose to the top to become one of last years best motocross bikes. For 2007, Kawasaki improves the championship winning KX250F with a host of engine and chassis modifications designed to extend its performance advantage. Side view of the 2007 KX250FSide view of the 2007 KX250FSide view of the 2007 KX250FSide view of the 2007 KX250FSide view of the 2007 KX250F Side view of the 2007 KX250F Refinements to Kawasaki’s highly acclaimed KX250F make it an eve…

2007 YAMAHAS

YZ450F New for 2007: Replacing the upper cast triple clamp with a light and strong forging, slightly reducing steering head rigidity, and the use of lighter outer fork tubes; lighter wheel rims and light wave-type brake rotors add up to super-accurate, super-responsive steering. Increasing the length of the rear shock by 1.5mm further sharpens handling. Replacing steel damping adjusters with aluminum ones removes even more weight from the four-way adjustable, titanium-sprung rear suspension unit. A more…

NEW BIKES: 2007 KAWASAKIS

  KX250F Kawasaki’s all-new four-stroke KX250F rose to the top to become one of last years best motocross bikes. For 2007, Kawasaki improves the championship-winning KX250F with a host of engine and chassis modifications designed to extend its performance advantage. Refinements to Kawasaki’s highly acclaimed KX250F make it an even more potent track weapon. The newest KX250F keeps the outstanding top-end power from last year’s bike, but adds a stronger pull from the bottom of its rev range. The upgr…

2007 SUZUKIS

RM 125  2007 RM125 Get ready for a shot of mid-range designed to help you blast past the competition. The RM125 has a wider powerband and more controllable power delivery than ever. Couple that smooth, strong power and refined suspension systems front and rear, and you’ve got the hottest one-two-five on the track. So get in on Suzuki’s winning tradition, with the 2007 RM125. RM-Z 250 2007 RM-Z250 The 2007 RM-Z250 is all new from the ground up and it is 100% Suzuki. The RM-Z250 features a compact, l…

2007 HONDA CRF450R

New for 2007 New larger 41mm Keihin FCR carburetor. New smaller exhaust valve for improved flow and smoother power delivery. Engine decompression system is lighter and more compact. New link-type front brake master cylinder improves front braking power by 15 percent. New Dunlop 742FA front tire for improved turning feel and traction. New subframe allows the muffler to be mounted farther forward for better mass-centralization. Lighter rear chain guide. Stronger clutch basket and clutch center for improve…

2007 HONDA CRF250R

New for 2007 New camshaft and cylinder-head porting improve power output above 8000 rpm. New intake valve springs match new camshaft. New crankcase venting for improved engine power. New exhaust header works in conjunction with new camshaft. New carburetor features new-styled accelerator pump and linkage for improved throttle response. New clutch basket features increased thickness for additional strength. New ignition map with 13,370-rpm rev limit. New link-type front brake master cylinder improves fro…

INSIDE KTM’S 2007 450SXF: ALL ELECTRIC START

(All photos by  Ray Archer)    KTM has unveiled it’s next generation of motocross machines at the second round of the FIM World Motocross Championship at Bellpuig, Spain last weekend. Factory rider Jonathan Barragan rode the 450 SXF to fourth place on it’s debut. It’s understood that Sebastian Tortelli was given the opportunity to ride the bike but decided to stick to his regular mount.          “I am really happy with the new bike,” Barragan s…