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WRENCH TECH: HONDA CRF450 TRANSMISSION UPDATE

One of the nifty features on the 2002 Honda CRF450 four-stroke is the separated oil cavities. Unlike a normal engine, the Honda has distinctly different oil compartments for top-end oil and transmission oil. This is a great idea, although by no means new. By separating engine oil from tranny oil, a CRF450 owner can use specialized fluids for each task. There is no cross contamination from sheared-off clutch particles, gear flashing and valve seats. What’s the downside? The available pool of oil is great…

HOW TO GET YAMAHA SECRET YZ125 NEEDLE

The MXA test crew has used a special needle in its 2002 YZ125. The original MXA needle was a works part that was hand made. During testing, the works needle performed better than the stock YZ125 needle. Unfortunately, the hand-made needle was not available through Yamaha dealers. Yamaha’s engineering department, urged on by their own in house test results, decided to work overtime to make the secret needle available to American racers. They ran a test program, verified the results and had Yamaha of Japa…

2002 HONDA CR125

Honda released pics and specs on their 2002 CRs. Here is all the info you need to know! (click on photo) CR125: The new list: 1. New third generation twin spar aluminum frame and swingarm. (1.1 lb lighter than last years frame) 2. Redesigned rear brake system with integrated reservoir and master cylinder. 3. New 36mm Mikuni TMX-X carburetor 4. Air intake boot reshaped and boot volume increased. 5. Exhaust port reshaped. 6. Redesigned 8mm longer exhaust header. 7. Taller first gear ratio and closer spacin…

2002 HONDA CR450F–APRIL 30

CRF450: 1. New third generation twin spar aluminum frame. (1.1 lb lighter than last years frame) 2. Redesigned rear brake system with integrated reservoir and master cylinder. 3. New Unicam valve train. 4. Pin-rotation type auto decompression release. 5. Hot start system. 6. Two 36mm titanium intake valves. 7. Two 31mm steel exhaust valves. 8. 96mm x 62.1mm bore and stroke. 9. Twin-sump lubrication system separates the oil supply for the crankshaft, piston, and valve train from the clutch and transmissi…

2002 HONDA CR250

(click on photo) CR250: 1. New third generation twin spar aluminum frame and swingarm. (1.1 lb lighter than last years frame) 2. Redesigned rear brake system with integrated reservoir and master cylinder. 3. All-new case-reed engine. 4. RC-style exhaust valves (similar to the CR125) with as electronic control module that uses engine rpm to calculate exhaust position and signal a DC servo motor to adjust the RC valve. 5. Magnesium clutch cover. 6. Showa suspension front and rear. 7. Aluminum spoke nipples…

YAMAHA DEBUTS THE YZ250F

Amidst all the hype surrounding the first outing of Honda’s RC450, Yamaha also debuted a new bike at the October 22nd race in Japan. That’s right, at the same mud race where Tortelli showed the world the RC450, Ernesto Fonseca proved to the world exactly what the YZ250F was capable of after months of rumors. Ernesto holeshot both motos and after a small battle with the locals, pulled out to a ten second victory in moto one and a twenty second victory in moto two. On hand at the event was the very proud …

SEE IT NOW! HONDA’S NEW FOUR-STROKE

Honda is a strange company. Less than a month ago they refused to tell or show their dealers any details on the CR450 four-stroke at the annual dealer meeting in Las Vegas. Now, they bring the bike out in public at this week’s Japanese race and allow a hoard of photogs to snap photos at will. Strange marketing! Honda dealers could have used the promo material on next year’s CR450 four-stroke to increase floor travel (and been in the know before their customers). HERE ARE THE CR450 FACTS The CR450 engine…

YAMAHA’S ALL-NEW 250 FOUR-STROKE

Believe it or not, Yamaha will race a four-stroke in the 125 class next year. No, not a 125cc four-stroke—a 250cc four-stroke. Under current AMA rules the 125 class is limited to 0-to-125cc two-strokes and 0-to-250cc four-strokes. The all-new Yamaha YZ250F (the F stands for Four-Stroke) is a down-sized version of the popular YZ426 (which is 250 class legal). But do not think that the YZ250F is a clone of the YZ426. In fact, it shares very few engine components with its big brother. Few engine parts ar…

2001 HONDA CR125 & CR250

Want to know what’s different on the 2001 CR125 compared to the CR250 other than a smaller motor? HERE’S WHAT’S NEW ON THE 2001 CR250 1. New cylinder port shapes and timing specs provide a smoother and stronger power delivery, and produce lightning-quick acceleration. 2. All-new lighter 38mm flat-slide Mikuni TMX carburetor adds both initial throttle crispness and improved throttle response to complement the new engine character. 3. New reed-petal stopper shape improves mid-range and high-rpm power deli…

2001 SUZUKI RM125!

Want to know what next year’s RM’s will look like (about six months before they release them)? Look no further. The 2001 RM’s will feature a totally new gas tank, new radiator wings, side panels, fender and front number plate. Insiders report that Kayaba will get the suspension contract for the 2001 RM250, but MXA’s spy photos reveal Showas on the 2001 RM125. Look for an external water pump, which will require new cases on both the 125 and 250. The 2001 engine is totally redesigned. The most noticeable …

THE 20-INCH TIRE REVOLUTION

Why are so many of the factory riders testing 20-inch front tires? Are they guinea pigs? What are the advantages and disadvantages of the new tire size? Is the 20-inch actually smaller than a 21-inch tire? Are consumers going to have to dig into their pockets to pony up for a 20-incher next year? What’s all the hype about?

MXA’S SECRET JETTING SPECS, 2003 And Back

We can’t tell you how to jet your bike. It’s a big world out there (and we don’t know you all that well). However, we can tell you what jetting we run in the MXA test fleet. Take into account that we race in a Mediterranean climate, near sea level, within sight of palm trees and never far from a Double Latte. We also run fresh 92-octane gas, work on our bikes every week, clean the filters, change pistons and rings regularly, are alert to pinging and haven’t changed oil brands in over a decade. This is t…