Browsing tag

KEIHIN

BLACK & WHITE: IS FUEL INJECTION A BLESSING OR A CURSE?

First and foremost, fuel injection on four-stroke motocross bikes is a fait accompli . No one is fighting it. It’s a done deal. The Yamaha YZ250F was the last holdout and they quit holding out this year. There is no going back to the venerable carburetor in motocross?even NASCAR was forced to bite the bullet in 2012. But, has it really changed anything about NASCAR or motocross? Throttle-body injection, as used on modern motocross bikes since the release of the 2008 Suzuki RM-Z450, was introduced to air…

MXA’S 2014 HONDA CRF450 MOTOCROSS TEST: SHERLOCK HOLMES NEEDS TO LOOK INTO THE CASE OF THE MISSING HORSEPOWER

FIRST AND FOREMOST, IS THE 2014 CRF450 BETTER THAN THE 2013 CRF450? A: Yes, but barely. Since the 2013 Honda CRF450 was a totally new model, save for the engine, it was unlikely that Honda would spend a lot of R&D cash on reworking the new design for 2014. But, Honda did focus their small R&D budget on improving some areas of concern. So, while the 2014 CRF450 isn?t new by any means, it is incrementally improved. Slip: It has six springs, but it needs stiffer springs to work. Q: WHAT DID HONDA C…

MXA TEAM TESTED: DICK’S RACING INTELAJET CARB MOD

        WHAT IS IT? Dick’s Racing progressively bores out the stock KTM 250SX two-stroke carb from 36mm to 39mm and installs the creative Intelajet system. It fits on all KTM two-stroke carbs from 2004 to 2012. WHAT’S IT COST? $425.00 (carb bored progressively from 36mm to 39mm with Intelajet installed); $30.00 (Intelajet mounting kit); $40.00 (taper-bore carb ends). CONTACT? www.dicksracing.com or (916) 722-2373. WHAT STANDS OUT? Here’s a list of things that stand out with Dick’s Ra…

MXA’S 2013 YAMAHA YZ125 TWO-STROKE TEST: THE LITTLE BIKE THAT COULD …IF ONLY SOMEONE WOULD GIVE IT A CHANCE

Q: FIRST AND FOREMOST, WHY DOES YAMAHA KEEP BUILDING AND MXA KEEP TESTING THE YZ125? A: It may sound melodramatic to say, but the YZ125 is the most important bike in modern motocross history. Not only was it a great race bike during its heyday, but there will come a time when every manufacturer, race promoter, rider and AMA functionary will rue the day that the AMA saotaged the 125cc two-stroke with its wholly unfair four-stroke displacement and fuel rules. We will all miss the 125 two-stroke when its g…

WE RIDE CYLINDER WORKS’ BIG-BORE KAWASAKI KX269F

It’s easy to think that Cylinder Works is pandering to cheaters with their line of big-bore engine kits. There is no doubt that cheaters are drawn to what Cylinder Works has to offer, but, in truth, most big-bore engine kits go to riders who are not bound by displacement rules (Vets, play riders and offroad racers). However, there could be just a hint of pandering to cheaters in that you can?t tell a 269cc Cylinder Works cylinder from a stock-bore OEM cylinder. (They even put the same casting numbers on…

MXA’S 2013 YAMAHA YZ250F MOTOCROSS TEST: THE MOST MODERNIZED VINTAGE BIKE ON THE MARKET TODAY

IS THE 2013 YZ250F BETTER THAN THE 2012 YZ250F? A: No! Is it worse? No. The 2013 Yamaha YZ250F is the same bike as last year, aside from the graphics, black handlebars and a white rear fender. It is, much like Dolly the sheep, a clone of the 2012 model. Q: HOW MANY CHANGES WERE MADE TO THE 2013 YAMAHA YZ250F? A: Didn?t you read the answer to the previous question? We weren?t joking. The 2013 Yamaha YZ250F has BNG (Bold New Graphics), black handlebars and a white rear fender instead of blue. Cosmetic upd…

MOTOCROSS ACTION TEST IMPRESSION: WHAT IT’S LIKE TO RACE THE 2013 KTM 250SX

2013 KTM 250SX: This is a 218-pound, two-stroke powered, 50-horsepower razor blade. MXA has a very simple test procedure ? we race. Yes, we sit through tech briefings, do studio photography, shoot action photos, get our ears blasted in the dyno room and spend long weekdays trying different settings, but in the end ? we race. With each race we switch test riders, rotating through Novice, Intermediate, Pro, Vet, old, young, fat, slim, smart and stupid test riders. We have fast test riders and we have slow…

EXCLUSIVE LOOK INSIDE THE KTM 450SXF-FE: THE BIKE THAT ROGER DECOSTER BUILT AND RYAN DUNGEY WON FOUR AMA SUPERCROSSES ON!

There is an inherent ?Hope Gene? in every person that believes that things will get better, that tomorrow is a better day, that good things come to those who wait and that this year’s new model is better than last year’s new model. And so it goes with motocross bikes. Even when we have positive proof that a bike hasn?t gotten better?people still run out and buy that bike…because it must be better…it just must be. We demand it! Which leads the MXA wrecking crew to the 2012 KTM 450SXF ?Factory Edition…

MXA’S 2012 HUSQVARNA TC250 MOTOCROSS TEST: SOMETHING GOOD CAME FROM BMW QUITTING FORMULA 1

Q: WHAT’S THE STORY WITH THE TC250? A: After flying under the U.S. radar for a few years, Husqvarna debuted the current-generation TC250 as a 2010 model. The big buzz was about its all-new ?X Lite? engine, which was touted as the smallest, lightest 250cc four-stroke engine in the class. At 48 pounds, it was a whopping 10 pounds lighter than its competitors? mills. The new-generation 2010 bike wasn?t all about the engine, as Husky went over the entire thing. Highlights included a specifically designed fr…

MXA’S 2012 HONDA CRF250 MOTOCROSS TEST: HONDA TRIES TO WORK ON THE FLAWS

Q: FIRST AND FOREMOST, IS THE 2012 HONDA CRF250 BETTER THAN THE 2011 CRF250? A: Yes! Is the 2012 Honda CRF250 significantly better than the 2011 model? No. Truth be told, Honda followed their typical strategy of making several minor updates instead of going whole hog. Why did Honda chip away at the CRF250’s bugaboos as opposed to starting from scratch? Let us review. (1) Economy. Unless you own oil reserves in the Middle East, you?ve been affected by the economy. Honda hasn?t been immune to the downward…

2011 KTM 250SXF MOTOCROSS TEST: THE BIKE THAT WON THE 250 WORLD CHAMPIONSHIP; WITH LINKAGE AND FUEL INJECTION

Q: FIRST AND FOREMOST, IS THE 2011 KTM 250SXF BETTER THAN THE 2010 KTM 250SXF? A: Yes. The one aspect of past KTM 250SXFs that we always hated was the linear, No-Doz powerband. It made lots of horsepower, but you had to wait for it. It was a no-hit, long draw-out, high-rpm powerband. In the hands of a really fast rider it could go really fast, but in the hands of an average rider it wasn’t so fast. Thankfully, the new fuel-injected 2011 KTM 250SXF doesn?t require any patience. It has an actual you-can-f…

2011 HONDA CRF250 MOTOCROSS TEST: HONDA BETS THE BANK ON A MINI-VERSION OF THE CRF450; WARTS AND ALL

Q: FIRST AND FOREMOST, IS THE 2011 HONDA CRF250 BETTER THAN THE 2010 HONDA CRF250? A: Yes. After going for the gusto in 2010 with an all-new CRF250, the Japanese manufacturer made a handful of changes for 2011. These updates were noticeable, but not earth-shattering. Suffice it to say that the 2011 Honda CRF250 is better than the 2010 model, but not resoundingly so. Q: HOW MANY CHANGES CAN BE FOUND ON THE 2011 CRF250? A: After Honda completely redesigned the CRF250 last year, we figured that the 2011 mo…

2011 YAMAHA YZ250 MOTOCROSS TEST: THE BIKE WE’D ALL BE RIDING IF THE AMA DIDN’T FAVOR FOUR-STROKES

Q: FIRST AND FOREMOST, IS THE 2011 YAMAHA YZ250 BETTER THAN THE 2010 YZ250? A: No. Although the 2011 YZ250 did get a few changes over the previous year, most of those changes were made to make it possible for Yamaha to sell the same bike in France that they do in Virginia. In the past, there have been Euro-spec and American-spec models that differ in jetting, compression and sometimes spring rates. Q: WHAT DID YAMAHA CHANGE FOR 2011? A: There were three changes from the 2010 Yamaha YZ250: (1) Silencer. …

2011 KTM 450SXF MOTOCROSS TEST: EVERYTHING YOU NEED TO KNOW ABOUT THE BIG-BORE KTM MOTOCROSS BIKE

Q: FIRST AND FOREMOST, IS THE 2011 KTM 450SXF BETTER THAN THE 2010 KTM 450SXF? A: Yes. Why? Because it has the same great brakes, superb handling and incredible powerband as last year in a smaller, shrink-wrapped package?all the good stuff in fancier attire. Q: HOW DOES THE KTM 450SXF ENGINE DIFFER FROM THE 350SXF? A: With the addition of the 350SXF to their line, KTM offers two bikes that are legal in the 450 class. On the whole, the two bikes share a lot of parts (plastic, wheels, brakes, suspension c…

FUTURE TECH: R&D’S INGENIUS THROTTLE BODY PROTOTYPE MIGHT ELIMINATE BUTTERFLIES

No butterfly means absolutely no obstruction to the airflow at 100 percent throttle opening. Given the fact that most motocross bikes use almost identical fuel-injection throttle bodies, it is surprising to learn that there are many different designs being used in the rest of the motorsports world. Ever since the development of the Bendix Electrojet for the 1957 Rambler Rebel, the throttle body has been the object of inventor attention. On fuel-injected engines, the throttle body is the part of the air …

2012 NEW MOTOCROSS BIKE BUYERS GUIDE: THE 2012 HONDA CRF50, CRF70, CRF80, CRF100, CRF150, CRF250 & CRF450

2012 HONDA CRF450 Press release: Since its introduction, the CRF450R has served as the standard by which all other bikes are judged in the big-bore class of motocross machines. In 2012, Honda raises the bar once again with a host of improvements that will help the CRF450R stay at the head of the pack. A new, stiffer fork outer among other refinements bring a more solid feel to the front end, and stiffer fork springs , revised suspension settings front and rear plus a new shock linkage yield improved tra…

2012 NEW MOTOCROSS BIKE BUYERS GUIDE: THE 2012 YAMAHA YZ450F & YZ250F (PLUS THE PLAY BIKES ARE BACK)

Yamaha has released photos and info on the 2012 YZ250F and YZ450F, but the bikes will not be in the showrooms until September 14. The YZ125 and YZ250 two-stroke info will not be unveiled until later. 2012 YAMAHA YZ450F There are new graphics, but the plastic remains the same on the blue 2012 YZ450F. Since the YZ450F was totally redesigned in 2010, it only gets modest upgrades for 2012. The focus of the 2012 changes were to improve midrange power, mellow out the low-end hit and improve the suspension fee…

2012 NEW MOTOCROSS BIKE BUYERS GUIDE: THE 2012 YAMAHA TWO-STROKES: YZ125 & YZ250

2012 YAMAHA YZ250 Yamaha won its first World Motocross Championship back in 1973?with the original YZ250 two-stroke. Today, featuring a lightweight, long-stroke engine that delivers an instant hit of free-revving power, the YZ250 is still the ultimate two-stroke race bike. (MXA note: Yamaha will not be releasing the 2012 bikes until September. The two-strokes will be included in the American lineup and, while these are official Yamaha photos of the 2012 YZ250 and YZ125, the American branch of Yamaha wil…

2012 NEW MOTOCROSS BIKE BUYERS GUIDE: THE 2012 KTM 450EXC ISN’T A MX BIKE, BUT IT DOES HAVE A FUEL-INJECTED, SIX-POUND LIGHTER, KTM 450 ENGINE

Here are the deets about the new 2012 450 EXC offroad engine (with the caveat that even though these are official KTM photos there could be changes between US and European models and between EXC and SFX specs?no guarantees). The EXC 450 engine will be fuel-injected (to meet emission standards in some areas), while the 450SXF will still be carbureteed…because it makes the best overall motocross-style powerband with the Keihin FCR. 450 ENGINE: Compared to the predecessors, the new 450EXC engine generati…

ASK THE MXPERTS: HOW DOES AN ACCELERATOR PUMP WORK?

Dear MXA,     I?m new to four-strokes. Can you tell me what an accelerator pump does? An accelerator pump is nothing more than a plunger that is designed to temporarily richen the mixture until the engine can produce enough air flow to pull the fuel through the jets. Just like a bathroom plunger, a rod pushes on a rubber diaphragm,which plunges into a reservoir of fuel, forcing the fuel into a small orifice, which leads to the intake tract. When you turn the throttle, a cam is activated b…

MXA TWO-STROKE NEWS: GAS GAS TWO-STROKE LINE FOR 2011 (125, 200, 250 & 300):

Gas Gas 250. Don?t confuse the Gas Gas enduro bikes with the Gas Gas trials bikes, while both are made at the Spanish boutique factory they are handled by different distributors. Gas Gas Offroad, a joint venture between brothers Clay and Ted Stuckey, distribute of the Spanish-built Gas Gas enduro line in the United States. There are no motocross bikes, but it would be possible to use the Gas Gas bikes for both (with a few mods) The four bike two-stroke line includes 125cc, 200cc, 250cc and 300cc two-str…

MOTOCROSS ACTION PRODUCT TEST: R&D RACING KEIHIN FCR POWER BOWL2:

WHAT IS IT? The Power Bowl2 is an upgraded version of the original R&D Power Bowl. It is a complete replacement float bowl, accelerator pump and leak jet that refines fuel flow on Keihin FCR carburetors. WHAT’S IT COST? $249.95 (fits all Keihin FCR carbs) . CONTACT? (562) 864-8218 or www.r1dean.com . WHAT’S IT DO? The Keihin FCR carb is an industrial miracle. It effectively processes the fuel/air mixture at all throttle settings via an ingenious series of orifices, circuits and tracts. As marvelous …

FIRST LOOK! 2011 HUSQVARNA TC449 MOTOCROSS BIKE PHOTOS & SPECS:

The side panels and rear number plates are all one piece. The frame is chromoly steel with the gas tank where the airbox would normally be and the airbox is behind the steerer tube (where the gas tank would normally be). The gas cap is located at the rear of the seat. The white plastic box behind the engine is an additional gas tank. The countershaft sprocket is in alignment with the swingarm pivot. 2011 HUSQVARNA TC449 SPECIFICATION Unlike typical rising rate linkage bikes, Husqvarna put the linkage on…