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MXA’S 2012 YAMAHA YZ250 MOTOCROSS TEST: NOT EVERYONE IS CUT OUT TO RACE A TWO-STROKE… IT TAKES A SPECIAL PERSON

May 18, 2012
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Q: FIRST AND FOREMOST, IS THE 2012 YAMAHA YZ250 BETTER THAN THE 2011 YZ250?

A: No. Last year, the 2012 YZ250 was changed slightly so that the same motocross bike sold in France could be sold in Texas. Prior to 2011, there were Euro-spec models and American-spec models. Most of the changes were in jetting, compression ratio, spring rates and mufflers.

Q: WHAT DID YAMAHA CHANGE FOR 2012?

A: Nothing, save for the yearly BNG (Bold New Graphics).

Q: WHAT HAS YAMAHA CHANGED ON THE YZ250 IN THE LAST EIGHT YEARS?

A: When you start looking at the big picture (groups of years instead of individual units), the YZ250 two-stroke has undergone a series of significant changes since this generation of the venerable YZ250 engine came on line.

2005. The old steel frame was dropped for a creative plug-and-play aluminum design that was four pounds lighter than the 2004 steel frame. In fact, the 2005 YZ250 was 7-1/2 pounds lighter than the 2004 YZ250. Additionally, the 2005 YZ got Honda-style front brake-hose routing and Renthal 7/8-inch aluminum handlebars.

2006. Yamaha kicked out the jams in 2006 with new suspension, a new rear brake caliper and a Ti shock spring. The most significant of the 2006 changes was the addition of Kayaba SSS suspension.


2012 Yamaha YZ250: If Yamaha would invest in new plastic and a better exhaust pipe, the YZ250 would be reborn. As it sits now, it is old looking and gives up easy horsepower to the KTM?250SX.

2007. The big change for 2007 was the swap to the N3EW needle that most hardcore racers had been using in 2006. The N3EW needle brought about a big improvement in bottom-end and midrange response from the 38mm Keihin PWK carburetor. In 2007, the 7/8-inch Renthals from 2005 were swapped out for 1-1/8-inch Renthal FatBars.

2008. Not a big year for mods, the 2008 YZ250 got a downsized front brake caliper, wave-style rotors and triple clamps with removable bar mounts.

2009. In 2009, Yamaha finally drop-kicked its massive steel front brake-hose clamp for a smaller and lighter aluminum clamp.

2010.
BNG.

2011. There were three changes from the 2010 Yamaha YZ250 (all designed to unify the product for worldwide distribution). First, the 2011 YZ250 got the 75mm-longer Euro-spec silencer. Second, the compression ratio was reduced from 10.9:1 to 10.6:1 by increasing the volume of the combustion chamber by 0.5cc. (This enabled the YZ250 to run a wider range of fuels available in both the USA and Europe.) Finally, Yamaha added a neutral ignition switch to retard the mapping when the bike was in neutral (to help beat sound tests).

2012 . BNG.



Q: IS THE 2012 YAMAHA YZ250 FASTER THAN THE 2012 KTM 250SX?

A: Heavens to Murgatroyd, no. Not even close. The 2012 Yamaha YZ250 makes the same amount of horsepower in 2012 that it made in 2005?and that won’t come close to touching the KTM 250SX.

On the dyno, the stock 2012 KTM pumps out 49.77 horsepower while the YZ250 is lucky to get to 46 horsepower. You don’t need a degree in astrophysics to see which rocket is going to get off the ground and which one is going to fizzle on the pad.

 
Time in a bottle: It would be easy to dismiss the YZ250 engine as an eight-year-old design that has seen better days, but nothing could be further from the truth. It’s old, but refined. 


Q: DOES THE YAMAHA YZ250 HANDLE BETTER THAN THE 2012 KTM 250SX?

A: No. The Austrians, with the help of their American test team, have finessed the KTM chromoly chassis to the nth degree. It tracks straight, carves without hesitation and doesn’t suffer from understeer. The Yamaha isn’t a bad-handling bike, but it is a little more reluctant to do all the things the KTM does without asking.

Q: IS THE YAMAHA YZ250 LIGHTER THAN THE KTM 250SX?

A: This is the subject of considerable discussion, because with the addition of the rising-rate linkage (as opposed to the no-link PDS system), the KTM 250SX gained 5 pounds, going from 212 pounds to 217 pounds. The extra 5 pounds pushed the KTM out of the ranks of the lightest bikes made. But did it push it past the YZ250’s weight? No. The KTM 250SX hits the scales at 217 pounds, while the Yamaha YZ250 is 218 pounds. With a change of tires, either bike could gain or lose a couple of pounds.

Q: IS THE YAMAHA YZ250 BETTER SUSPENDED THAN THE KTM 250SX?

A: Yes, indeed. Nothing?and we mean nothing?is as well suspended as a Kayaba SSS-equipped Yamaha. “SSS” is the acronym for “Speed Sensitive System,” which means that the damping is determined by the speed at which the piston moves though the cartridge rod?not its position in the stroke of the fork. Kayaba SSS forks are 90 percent speed sensitive, whereas their position-sensitive competition is only 30 percent speed sensitive. The suspension on the KTM 250SX is a hot mess. For some reason, KTM two-strokes come with Euro-spec spring rates, while the KTM four-strokes get American-spec spring rates. To race the 2012 KTM 250SX, a rider needs to drop the 0.44 fork spring and 5.4 shock spring and go to stiffer coils (typically a 0.48 fork spring and a 5.7 shock spring). Even then, the KTM’s WP forks can’t compete head to head against the YZ’s Kayabas.

Q: IS THE 2012 YAMAHA YZ250 LESS EXPENSIVE THAN THE KTM 250SX?

A: No. The KTM 250SX ($6899) is $250 cheaper than the YZ250 ($7150). The fly in the ointment of both of these bikes is that they sell out fast?not necessarily because there is an overwhelming demand for them, but because the production numbers are low, thus demand always exceeds supply.

Q: CAN YOU MAKE THE 2012 YAMAHA YZ250 AS POWERFUL AS THE 2012 KTM 250SX?

A: Eight years of neglect is hard to overcome. The YZ250 engine design is long in the tooth?and it really hasn’t received much in the way of upgrades over the years. If, however, you want to try to make the YZ250 better, start with these four mods.

(1) Exhaust pipe.
You can gain two horsepower with an FMF or Pro Circuit pipe. Although you might think that this will help close the gap with the more powerful KTM 250SX, that is only true if the KTM rider doesn’t install an FMF or Pro Circuit pipe.

(2) Moto Tassinari reeds. The Moto Tassinari reed is a simple modification that makes a noticeable difference in midrange power. By the way, the KTM 250SX comes stock with Moto Tassinari reeds. Moto Tassinari’s phone number is (603) 298-6646.

(3) Gearing.
  Every MXA test rider adds one tooth to the YZ250’s rear sprocket. The goal is to gear it down to get to third gear sooner. The lower gearing makes the bike accelerate quicker.


Silencer: Over the years the silencer has gotten longer, but the reducing ring in the end cap helps save the power output.
 

 
Spit and chew: Imagine what could be if the manufacturers had spent four-stroke R&D?dollars on two-strokes.


Q: HOW IS THE STOCK JETTING?

A: Way back in 2007, Yamaha spec’ed the YZ250 with a N3EW needle and eliminated the worst of the pinging?although if you hop-up the YZ250 or add an aftermarket exhaust pipe, you will need to go to a bigger 180 or 182 mainjet. Other than looking out for pinging, the 2012 Yamaha YZ250 jetting is basic and simple. MXA‘s recommended 2012 YZ250 jetting is as follows:
   Mainjet:
178
   Pilot jet:
50
   Needle:
N3EW
   Clip:
2nd from top
   Air screw:
1 turn out
   Note:
The air screw is very sensitive from 1/2 turn to 1 turn out.

Q: WHAT WAS OUR BEST FORK SETTING?
 
A: These are awesome forks. Yamaha’s speed-sensitive damping is terrific, and it is made all the more terrific by the light feel and snappy input of the two-stroke engine. Obviously, if you are fast or fat, you will have to go stiffer on the fork springs. For hardcore racing, these are MXA‘s recommended 2012 Yamaha YZ250 fork settings:
   Spring rate:
0.43 kg/mm
   Oil height:
330cc
   Compression:
13 clicks out
   Rebound:
14 clicks out
   Fork leg height:
5mm up
   Note:
On Yamaha’s SSS forks, there is some crossover between the rebound damping and compression damping, which means that turning the rebound in will make the forks not only slower on rebound, but stiffer in compression.

Q: WHAT ABOUT THE REAR SUSPENSION?

A: Compared to what comes on every other bike sold, the YZ250 has a works shock. Not only does it have a jumbo-sized 18mm shock shaft, Kashima-coated internals and SSS damping, but it comes stock with a $650 titanium shock spring. For hardcore racing, these are MXA‘s recommended 2012 Yamaha YZ250 settings:
   Spring rate:
4.9 kg/mm
   Race sag:
100mm
   Hi-compression:
1-3/4 turns out (1-1/2 turns out stock)
   Lo-compression:
8 clicks out (13 clicks out stock)
   Rebound:
8 clicks out (12 clicks out stock)
   Note:
Yamaha’s high-speed compression clicker (the large dial) is very sensitive to adjustment. Make small (1/8th turn) changes. Use the high-speed adjuster to set the bike’s fore/aft bias at speed. National speed riders and heavyweight contenders will need to move up to a 5.0 kg/mm spring.

Q: ARE TWO-STROKES OBSOLETE?

A: What would you say if we wanted to sell you a bike that weighed 20 pounds more, was 20 percent more expensive, had lots of extra moving parts, couldn’t be repaired without an ohmmeter, and made less power per cubic centimeter? Interested in that bike? Sure you are?because most likely you have a modern four-stroke sitting in your garage.

Let’s dispel the idea that four-strokes are more powerful than two-strokes. They aren’t?never have been and never will be. Yes, a 450 four-stroke does make more power and torque than a 250 two-stroke, but it’s all done with smoke and mirrors. Four-strokes are only competitive with two-strokes because they are larger. Cubic centimeter to cubic centimeter, a two-stroke is the most powerful motocross weapon made. Take away the 200cc displacement advantage and the horsepower-and-torque crown goes to a two-stroke…to the tune of 15 ponies.


Ying and yang: The absolutely awesome front forks are mated to a very pedestrian front brake.

Q: WHAT DID WE HATE?

A: The hate list:

(1) R&D. As it sits, the YZ250 is an eight-year-old motorcycle sitting on super-modern suspension components. In the hands of a talented rider on a rough track, that combination is good enough to win. But, if a KTM 250SX rider upgraded his suspension, he’d be sitting on a brand-new bike with brand-new suspension. That combination isn’t beatable by the antique YZ250.

Q: WHAT DID WE LIKE?

A: The like list:

(1) Maintenance costs. In reality, a two-stroke isn’t any cheaper on a season-per-season basis when compared to a four-stroke. Yes, its parts are twice as cheap, but it still needs them at regular intervals. Where the YZ250 romps on the typical four-stroke is when a catastrophic blowup occurs. In that case, the YZ250 could blow up four times before you’d spend as much money as one explosion would cost on a four-stroke.

(2) Garage mechanic. Anybody with a nutcracker and a butter knife could rebuild the top end on a YZ250 two-stroke. Few racers have the tools, know-how or enthusiasm to rebuild a four-stroke.

(3) Titanium shock spring . Yamaha took the Ti shock spring off its four-stroke line several years ago, but the YZ250 still has the high-tech titanium shock spring. It would cost $650 to buy this spring from your dealer.

(4) Suspension. You gotta love Yamaha’s SSS suspension. It is perfect right off the showroom floor.

Q: WHAT DO WE REALLY THINK?

A: Not everyone is cut out to race a two-stroke. Who is? As Roger DeCoster said last year, “It takes a more talented rider to race the two-stroke, and I can see where it would be difficult for most of the current 250 four-stroke riders to make the change.” Are you like most of the current 250 four-stroke riders?

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