THE ULTIMATE 2010 YAMAHA YZ250F EXHAUST:

March 20, 2010
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The 2010 Yamaha YZ250F is a pleasant bike, but it comes up short in the kind of power that it needs to get the job done. Designed with a low-to-mid powerband and a flat top-end, the YZ250F engine is in desperate need of help. To fix the 2010 YZ250F, the MXA wrecking crew gathered up six different exhaust systems to test. Our goal? More power!

As with any test, we have caveats: We tested the exhaust systems as they were sent to us. We didn’t add any reducing cones to make the pipes quieter. We didn’t put more hours on one pipe than another before sound testing them. We never let test riders talk to each other during test sessions. We used the dyno as a check system, but placed the most emphasis on test rider input.

These are our results. The best 2010 Yamaha YZ250F pipe for you is in here—find it.

STOCK?2010 YAMAHA YZ250F EXHAUST

Thanks to a totally new frame, the 2010 Yamaha YZ250F exhaust system is new from the ground up. It features a two-step design (45.0mm head pipe to 50.8mm midpipe), 50mm longer muffler, wider-pitch perforated core and smaller 41.2mm core).

WHAT ARE THE STOCK DYNO NUMBERS?
   A dyno isn’t a foolproof indicator of how an exhaust system will perform. It provides statistics that can be used for analysis and interpretation, but by no means does it have the final say. The MXA wrecking crew ran each of the six 2010 Yamaha YZ250F exhaust systems on the dyno and took an in-depth look at our findings. Here are the stock YZ250F numbers. Gain/loss refers to how much horsepower the aftermarket pipes gained or lost over the stock pipe.

RPM      HORSEPOWER      GAIN/LOSS
7000              24.1                  +0
8000              29.0                  +0
9000              32.1                  +0
10,000           33.1                  +0
11,000           35.5                  +0
12,000           36.4                  +0

WHAT IS ITS DURATION ABOVE 34 HORSEPOWER?
   2300 rpm. As a measure of the quality of the overall powerband, we studied when the YZ250F reached 34 horsepower and for how long it stayed above that mark (in rpm). The stock YZ250F exhaust pipe hit 34 horsepower at 10,400 rpm and stayed there to 12,700 rpm. That is a 2300 rpm range. The 2300 rpm range above 34 horsepower was the baseline setting that every other exhaust pipe was compared to.

WHAT IS THE PEAK HORSEPOWER?
   36.6 horsepower at 11,700 rpm (this is misleading because the stocker makes its most useful power below 10,000 rpm).

WILL IT PASS THE AMA SOUND TEST?
   Yes. In order to pass the AMA’s loose, 94 dB sound rule, an exhaust system can measure up to 95.9 dB and still pass. Under AMA and FIM rules, 250cc four-strokes are tested at a mandated 5000 rpm. The stock YZ250F exhaust produced a very acceptable 94.5 dB.

WHAT’S IT COST?
   $971.18.

WHOM DO I CONTACT?
   Your local Yamaha dealer.

MXA TEST RIDER COMMENTS:

“The stock pipe provides brisk acceleration off the bottom end, but signs off too quickly in the middle of the powerband. It revs all the way to the rev limiter, but it doesn’t pull.”

“It pulled hard off the bottom, but ran flat from the middle on.”

“It is rider-friendly, but intermediate and pro-level riders will be left wanting more. It revs to the limiter, but doesn’t do much work after the midrange.”

“The stock system makes good power off the bottom and into the midrange, but it’s flat on top.”

“The powerband is low-to-low. It revs and makes noise, but the best work is done well below 8500 rpm.”

“This pipe produces too short a powerband. You have to shift too often. It doesn’t pull far enough.”

DUBACH RACING/DEVELOPMENT (DR.D) EXHAUST

If anyone knows the shortcomings of the stock Yamaha YZ250F exhaust system it is Doug Dubach of Dubach Racing & Development (DR.D). Dubach is Yamaha’s official in-house test rider and does all of the R&D work on the new blue bikes during prototype and pre-pro testing.

WHAT ARE THE DR.D DYNO NUMBERS?
   Here are DR.D’s numbers and their relationship to the stock numbers (with the stock YZ250F horsepower numbers in parentheses).

RPM         HORSEPOWER      GAIN/LOSS
7000         22.2 (24.1 stock)      -1.9
8000         29.1 (29.0 stock)      +0.1
9000         32.8 (32.1 stock)      +0.7
10,000      35.4 (33.1 stock)      +2.3
11,000      37.0 (35.5 stock)      +1.5
12,000      36.8 (36.4 stock)      +0.4

WHAT IS ITS DURATION ABOVE 34 HORSEPOWER?
   3400 rpm. The DR.D exhaust pipe hit 34 horsepower at 9400 rpm and stayed there to 12,800 rpm. The DR.D pipe stayed above 34 horsepower for 1100 rpm more than the stocker.
 
WHAT IS THE PEAK HORSEPOWER?
   37.2
horsepower at 11,400 rpm. The stock pipe made 36.6 horsepower at peak.

WILL IT PASS THE AMA SOUND TEST?
   Yes. The DR.D exhaust system produced 95.5 dB, while the stock exhaust produced 94.5 dB.

WHAT’S IT COST?
   $879.95 (carbon/Ti), $779.95 (Ti/Ti), $679.95 (stainless/carbon), $549.95 (stainless/aluminum).

WHOM DO I CONTACT?
www.dubachracing.com or (951) 808-1114.

MXA TEST RIDER COMMENTS:

“The YZ250F has so much bottom end that DR.D was willing to give some away in order to produce a harder hit and longer pull over the top.”

“The DR.D system offered a good amount of mid-to-top power and was stronger in those areas than the stock system.”

“It’s a pipe that is best suited to faster and more experienced riders. It gives up bottom to give breadth across the top. It’s a good trade-off.”

“The exhaust signs off later than the stocker and pulls much harder through the middle, but it runs at its best across the midrange.”

“I could tell that it gave up a little bottom, but I don’t really need power below 7000 rpm on a 250F. In fact, I don’t need power below 10,000 rpm.”

VANCE AND HINES XCR SLIP-ON EXHAUST

In this test, we tested both complete exhaust systems and slip-ons. A slip-on exhaust uses the stock head pipe, but replaces the midpipe and muffler. The biggest benefit of a slip-on is that it costs about half of what a complete exhaust system costs. The Vance and Hines XCR slip-on only costs $299 and made good horsepower.

WHAT ARE THE VANCE AND HINES DYNO NUMBERS?
   Here are the Vance and Hines numbers and their relationship to the stock numbers (with the stock YZ250F horsepower numbers in parentheses).

RPM         HORSEPOWER      GAIN/LOSS
7000         24.0 (24.1 stock)      -0.1
8000         29.2 (29.0 stock)      +0.2
9000         32.2 (32.1 stock)      +0.1
10,000      34.5 (33.1 stock)      +1.4
11,000      36.4 (35.5 stock)      +0.9
12,000      37.2 (36.4 stock)      +0.8

WHAT IS ITS DURATION ABOVE 34 HORSEPOWER?
   3200 rpm. The Vance and Hines slip-on hit 34 horsepower from 9800 rpm and stayed there to 13,000 rpm. The Vance and Hines pipe stayed above 34 horsepower for 900 rpm more than the stocker

WHAT IS THE PEAK HORSEPOWER?
   37.3
horsepower at 11,800 rpm. The stock pipe made 36.6 horsepower at peak.

WILL IT PASS THE AMA SOUND TEST?
   Yes. The Vance And Hines XCR slip-on produced 94.3 dB, while the stock exhaust produced 94.5 dB.

WHAT’S IT COST?
   $299.00 (XCR Slip-on), $849.95 (TiPro complete system), $499.00 (stainless/aluminum complete system).

WHOM DO I CONTACT?
www.vanceandhines.com or (562) 921-7461.

MXA TEST RIDER COMMENTS:

“I was surprised at the drastic improvement that a slip-on could make. I was really impressed with the width of the powerband. It had good acceleration.”

“It traded some of the bottom-end power for more midrange?luckily, the YZ250F has a lot of bottom-end power to give away.”

“It felt the same as the stock system off the bottom, but it gave the bike a super race-like feel in the midrange.”

“For the price, this was a very good pipe. It added power in the right places.”

“Overall, the Vance and Hines system improved the YZ250F in the midrange and extended the powerband higher into the top-end. It made the YZ250F much more rideable. For a slip-on, this is a very good pipe.”

PRO CIRCUIT Ti4 EXHAUST SYSTEM

Pro Circuit’s Ti-4R is their highest-priced full-race system. It comes with extra packing and a welded end cap. For riders who want the same performance for less, Pro Circuit offers the exact same dimensions in a stainless steel version (T-4R), but without the welded end cap and exotic Ti construction.

WHAT ARE THE PRO CIRCUIT DYNO NUMBERS?
   Here are Pro Circuit’s numbers (with the stock YZ250F horsepower numbers in parentheses).

RPM         HORSEPOWER      GAIN/LOSS
7000         24.0 (24.1 stock)      -0.1
8000         28.7 (29.0 stock)      -0.2
9000         33.1 (32.1 stock)      +0.2
10,000      35.5 (33.1 stock)      +2.4
11,000      37.1 (35.5 stock)      +1.5
12,000      34.8 (36.4 stock)      +0.4

WHAT IS ITS DURATION ABOVE 34 HORSEPOWER?
   3100 rpm. The Pro Circuit Ti-4R exhaust pipe hit 34 horsepower at 9900 rpm and stayed there to 13,000 rpm. The Pro Circuit pipe stayed above 34 horsepower for 800 rpm more than the stocker.

WHAT IS THE PEAK HORSEPOWER?
   37.3 horsepower at 11,200 rpm. The stock pipe made 36.6 horsepower at peak.

WILL IT PASS THE AMA SOUND TEST?
   Yes. The Pro Circuit exhaust system produced 94.5 dB, while the stock exhaust produced an identical 94.5 dB.

WHAT’S IT COST?
   $999.95 (Ti-4R), $899.95 (Ti-4 GP), $779.95 (T-4 GP), $779.95 (T4-R). Pro Circuit and FMF are offering 20 percent off of these prices until March 1, 2010.

WHOM DO I CONTACT?
www.procircuit.com or (951) 738-8050.

MXA TEST RIDER COMMENTS:

“I really like the way this exhaust system worked. It gave away some of the more-than-abundant bottom end, but replaced it with improved mid-and-up power.”

“This exhaust is a do-it-all kind of system. I didn’t notice that it lost any low end because it seemed to pull really strong where I needed it to. Once in the middle, it seemed to gain a head of steam and rocket into the top end.”

“The Pro Circuit exhaust is best suited to intermediate and pro-level riders.”

“As far as feel, the Pro Circuit pipe came on really strong from the midrange onward.”

“This is the most pro-level of any pipe in the test. It probably wouldn’t suit a novice as well as a fast rider because it trades some bottom-end response (which slower riders will probably miss) for the freest revving top of any of the pipes.”

FMF FACTORY 4.1 EXHAUST SYSTEM

As you would expect from FMF’s patented resonance chamber, the Factory FMF 4.1 makes full use of the unique chambers to maximize power and minimize sound. Not only does the FMF 4.1 come with a MegaBomb resonance chamber-equipped head pipe, but a small resonator is hidden inside the front section of the muffler.

WHAT ARE THE FMF DYNO NUMBERS?
   Here are the FMF’s numbers and their relationship to the stock numbers (with the stock YZ250F horsepower numbers in parentheses).

RPM         HORSEPOWER      GAIN/LOSS
7000         23.5 (24.1 stock)      -0.6
8000         29.1 (29.0 stock)      +0.1
9000         32.3 (32.1 stock)      +0.2
10,000      34.9 (33.1 stock)      +1.8
11,000      36.6 (35.5 stock)      +1.1
12,000      36.9 (36.4 stock)      +0.5

WHAT IS ITS DURATION ABOVE 34 HORSEPOWER?
   3200 rpm. The FMF Factory 4.1 exhaust pipe hit 34 horsepower at 9800 rpm and stayed there to 13,000 rpm. The FMF pipe stayed above 34 horsepower for 900 rpm more than the stocker.

WHAT IS THE PEAK HORSEPOWER?
   37.2
horsepower at 11,800 rpm. The stock pipe made 36.6 horsepower at peak.

WILL IT PASS THE AMA SOUND TEST?
   Yes. The FMF exhaust pipe produced 95.7 dB, while the stock exhaust produced 94.5 dB.

WHAT’S IT COST?
   $949.99 (carbon 4.1 w/MegaBomb), $849.99 (Ti 4.1 w/MegaBomb). FMF and Pro Circuit F are offering 20 percent off of these prices until March 1, 2010.

WHOM DO I CONTACT?
www.fmfracing.com or (310) 631-4363.

MXA TEST RIDER COMMENTS:

“It had a decent amount of hit in the bottom end, a strong surge through the midrange, and was fair in the top-end.”      


“I wanted more power in the top-end punch, but liked the long duration of the FMF’s powerband.”


“The FMF pipe felt like the fastest exhaust of all the pipes in this test. I liked it because it made power in a usable manner.”


“Low-to-mid power is strong. It revs slower than the other pipes, but it makes really good power in the midrange. Perhaps the dual resonance chambers cause the top end to go flat.”


“This exhaust system suits the widest range of riders. Everyone except for pro-level riders would find the FMF system to be beneficial.”

YOSHIMURA RS-2 EXHAUST

Yoshimura has built a reputation for superb quality, and the Yamaha YZ250F pipe didn’t disappoint. It is a clean design with nice welds and cool looks. It is offered in three different price ranges, based on the material used (titanium, carbon fiber or aluminum).

WHAT ARE THE YOSHIMURA DYNO NUMBERS?
   Here are Yoshimura’s numbers and their relationship to the stock numbers (with the stock YZ250F horsepower numbers in parentheses).

RPM         HORSEPOWER      GAIN/LOSS
7000         24.3 (24.1 stock)      +0.2
8000         29.0 (29.0 stock)      +0.0
9000         32.2 (32.1 stock)      +0.1
10,000      34.4 (33.1 stock)      +1.3
11,000      36.4 (35.5 stock)      +0.9
12,000      37.1 (36.4 stock)      +0.7

WHAT IS ITS DURATION ABOVE 34 HORSEPOWER?
   3100 rpm. The Yoshimura RS-2 exhaust pipe hit 34 horsepower at 9900 rpm and stayed there to 13,000 rpm. The Yoshimura pipe stayed above 34 horsepower for 800 rpm more than the stocker.

WHAT IS THE PEAK HORSEPOWER?
   37.2 horsepower at 11,700 rpm. The stock pipe made 36.6 horsepower at peak.

WILL IT PASS THE AMA SOUND TEST?
   Yes. The Yoshimura exhaust system produced 93.5 dB, while the stock exhaust produced 94.5 dB. This was the quietest pipe in the test.

WHAT’S IT COST?
   $895.00 (Ti/carbon), $845.00 (Ti/Ti), $595.00 (stainless/aluminum).

WHOM DO I CONTACT?
www.yoshimura-rd.com or (800) 634-9166.

MXA TEST RIDER COMMENTS:

“This was my favorite exhaust system of the entire test, hands down.”

“I noticed a slight hesitation off idle, which can be fixed with the next smallest pilot jet. When it came to life, it nearly pulled my arms out of their sockets!”

“I was hoping for more top-end power, but I think I said that about almost every pipe.”

“The Yoshimura pipe was very lively. It was a fun pipe to ride and had a race-like feel.”

“The way the powerband hit and its increased width were the highlights of the Yoshimura RS-2.”

“The Yoshimura pipe will be liked by every level of rider. It is responsive, quiet and makes the YZ250F scream.”


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