The Yamaha YZ250F is the newest fuel-injected 250cc motocross bike. It makes its best power from low to mid, but is still usable on top . It is fast, makes over 40 horsepower and has an effective powerband. When quizzed about what they wanted out of an aftermarket YZ250F pipe, most MXA test riders wanted to trade some low end in favor of more top—some wanted to get rid of the barky hit off the bottom, all wanted a broader all-around powerband, and a few were very happy with the stock powerband.

You would think that the definition of an impossible task would be fulfilling the MXA test riders’ wish lists. Not so! Every exhaust pipe that we tested solved at least one of the MXA test riders’ needs. It should be noted that the stock Yamaha YZ250F pipe is one of the best production pipes we have ever seen. Most riders could live happily ever after with the stock pipe, but the aftermarket pipes do offer a variety of powerbands, rpm ranges, torque windows and performance styles. They may not blow the stock YZ250F pipe away on the dyno, but they offer refined power profiles that suit a wider range of riders.

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

STOCK YZ250F: THE BEST OEM PIPE EVER

For their first fuel-injected 250, Yamaha produced a likable and usable powerband. It hits hard down low (and feels jittery because of the jerky power delivery). But after the hard hit, it surges into the middle with a very strong pull. This is a very good powerband with the caveat that it gets to the revlimiter very quickly—and it has a nasty, raspy, soft rev limiter.

MXA TEST RIDER COMMENTS:

“The stock pipe is a little too barky right off idle. This catches you off guard sometimes coming out of tight turns.”

“This is a very good production pipe from the bottom to the middle, but it is flat on top. It is best to shift at peak or before.”

“I like this pipe because it revs okay, is easy to ride in the midrange, and is rider-friendly. It is a great pipe for a production bike.”

“The stock pipe is smooth, mellow and focused on the lower half of the powerband. It’s peppy in the middle but falls off the pipe quickly.”

WHAT SKILL LEVEL IS IT BEST SUITED FOR?

Novice or Vet. It has a very usable powerband that allows Novices and Vets to get the most out of what it has to offer. Faster Intermediates and Pros will push over its limit.

WHAT ARE THE STOCK DYNO NUMBERS?

Here are the stock YZ250F numbers.

RPM…………..HORSEPOWER
7000 ………………25.06
8000………………29.69
9000………………34.47
10,000……………37.61
11,000…………….39.63
12,000…………….40.99
Peak HP…………. 41.63 @ 12,300 rpm
Peak torque…….. 20.21 ft/lb. @ 8700 rpm

TEST RIDER RATING OUT OF SIX

Novice….. Third
Vet………..Sixth
Pro………..Sixth
Overall….Sixth

WHAT’S THE SQUAWK?

The stock pipe has more clamps than a nuclear submarine.

WHAT’S IT COST?

$971.18.

WHOM DO I CONTACT?

Your local Yamaha dealer.

DR.D NS-4: THE WITH PERSONALITY

Test riders raved about the power delivery of the DR.D NS-4 exhaust system. It brought the YZ250F to life, punctuated its attributes and erased its flaws. This is a solid exhaust system that is well-made and unique looking. Equally important, it was the least expensive pipe in the shootout, which translates into bang for the buck.

MXA TEST RIDER COMMENTS:

“The DR.D pipe is the most fun to ride with. It mellows out the transition off the bottom and mates it to an explosive midrange.”

“The DR.D pipe delivered the most excitement. It had the broadest overall powerband.”

“The midrange was where this pipe shined. It was very strong and very usable. It’s a rider’s pipe, not a dyno pipe. It has the kind of power you want.”

“The DR.D pipe had the most character. It had decent bottom, amazing midrange and adequate top. The top wasn’t bad, but this wasn’t a high-rpm pipe by any means.”

WHAT SKILL LEVEL IS IT BEST SUITED FOR?

Pro and Vet. It should be no surprise that a pipe built by Yamaha’s official test rider and a 22-time World Vet Champion would have the perfect powerband for Veteran racers.

WHAT ARE THE DR.D DYNO NUMBERS?

Here are DR.D’s numbers with the stock YZ250F horsepower numbers in parentheses.

RPM………… HORSEPOWER
7000………………25.07 (25.06)
8000……………..30.07 (29.69)
9000………………34.27 (34.47)
10,000……………37.21 (37.61)
11,000………….. 39.58 (39.63)
12,000……………41.20 (40.99)
Peak HP……….. 41.631 @ 12,300 rpm
Peak torque….. 20.52 ft/lb. @ 8900 rpm

TEST RIDER RATING OUT OF SIX

Novice…..Fourth
Vet……… Second
Pro……… Second
Overall… Second

WHAT’S THE SQUAWK?

It was the loudest pipe in the test. The HGS Bud Racing pipe was the quietest. We loved the fact that the DR.D pipe didn’t use any springs but slip-fit together instead.

WHAT’S IT COST?

$599.95 (stainless/aluminum/magnesium end cap).

WHOM DO I CONTACT?

www.dubachracing.com or (877) 382-2261.

FMF RACING FACTORY 4.1: SMOOTH AS SILK

Some pipes in this shootout went for more hit or higher rpm, while the FMF Factory 4.1 RCT worked on the total picture. It magnified every aspect of the YZ250F powerband. It produced the smoothest power and did the best job of filling in the dips and surges of the stock system. It made more horsepower than stock at every step on the dyno curve and made it in a way that was easily utilized.

MXA TEST RIDER COMMENTS:

“FMF has built a seamless powerband that has something for everybody. It takes out the stocker’s low-end abruptness and irons out all the burps and burbles.”

“It starts out mellow off the bottom, which makes the bike more manageable in tight turns, but picks up as soon as it starts to climb into the middle. It doesn’t rev any higher than the stock pipe.”

“It’s not super at the crack of the throttle; it builds power in a metered manner. Compared to the stock pipe, it freed up the engine and made the bike feel lighter.”

“The FMF pipe mimics the stock powerband, but produces more power virtually everywhere. Its biggest plus is that it doesn’t feel aggressive or scary—it just smooths out the peaks and valleys to make the power very usable.”

WHAT SKILL LEVEL IS IT BEST SUITED FOR?

Novice, Intermediate and Pro. It has a good, broad powerband that suits a wide range of skills.

WHAT ARE THE FMF DYNO NUMBERS?

Here are the FMF’s numbers with the stock YZ250F horsepower numbers in parentheses.

RPM………………HORSEPOWER
7000………………….25.17 (25.06)
8000………………… 29.85 (29.69)
9000………………… 35.31 (34.47)
10,000……………… 38.29 (37.61)
11,000……………….40.07 (39.63)
12,000……………… 41.49 (40.99)
Peak HP……………. 41.61 @ 12,300 rpm
Peak torque………. 20.60 ft/lb. @ 9000 rpm

TEST RIDER RATING OUT OF SIX

Novice……. Fifth
Vet…………Fifth
Pro……….. Fourth
Overall…..Fourth

WHAT’S THE SQUAWK?

No real complaints.

WHAT’S IT COST?

$949.99 (Ti/Ti/ carbon end cap), $899.99 (Ti/Ti/Ti end cap), $824.98 (stainless/aluminum/carbon end cap).

WHOM DO I CONTACT?

www.fmfracing.com or (310) 631-4363.

HGS/BUD RACING: THE MOST PEAK HORSEPOWER

HGS exhausts are new to the American market but are very popular in Europe. Bud Racing USA is the importer for these systems. The HGS/Bud Racing YZ250F exhaust is more focused on the midrange than any other pipe in this shootout. Every MXA test rider raved about the position and output of this European pipe. It has lots of power, but the least skilled and the most skilled found the HGS powerband to be an acquired taste.

MXA TEST RIDER COMMENTS:

“When you used the midrange on this pipe, it rewarded you; but, if you let it get down into the low revs, it took a while to get back on the pipe.”

“This is definitely a powerful exhaust pipe. It was forceful but challenging to get the most out of it. It had a nice midrange window of power, but you had to be preparred for it to make it work.”

“There is a little dip between the bottom and midrange—more of a hiccup really, and the hiccup made the midrange power seem all the more impressive because it came on quick.”

“It chugs more than any other pipe in this test under deceleration. The bottom was fair, midrange impressive and top end very good.”

WHAT SKILL LEVEL IS IT BEST SUITED FOR?

Vet. Our Novice test riders felt that the powerband was a little tricky to work with, while the Vets really synced with the midrange powerband. The Pros agreed with the Novices.

WHAT ARE THE HGS/BUD DYNO NUMBERS?

Here are the HGS/Bud Racing’s numbers with the stock YZ250F horsepower numbers in parentheses.

RPM…………….HORSEPOWER
7000……………….25.22 (25.06)
8000………………29.72 (29.69)
9000……………….35.11 (34.47)
10,000…………… 37.61 (37.61)
11,000…………… 40.13 (39.63)
12,000…………… 41.72 (40.99)
Peak HP…………. 41.87 @ 12,200 rpm
Peak torque……. 20.42 ft/lb. @ 8900 rpm

TEST RIDER RATING OUT OF SIX

Novice………Sixth
Vet…………..Third
Pro…………. Fifth
Overall …… Fifth

WHAT’S THE SQUAWK?

HGS forgot to weld on the pipe bracket that holds the bottom of the right side panel. This was a major inconvenience. It was also the hardest pipe to install—not a plus on a bike that is already very hard to put pipes on.

WHAT’S IT COST?

$695.00 (stainless/stainless/carbon end cap).

WHOM DO I CONTACT?

www.budracing-usa.com or (951) 245-2660.

PRO CIRCUIT RACING TI-6: FASTEST PIPE FOR FAST RIDERS

For 2014, Pro Circuit introduced its new T-6 and Ti-6 systems. The 6-series caters more to the needs of regular racers and doesn’t try to meet the restrictive AMA/FIM Pro racing sound rules. The result is more horsepower while still meeting Amateur sound levels. Pro Circuit’s YZ250F system is focused on Pro-level riders or, at the very least, riders who don’t feel compelled to shut off.

MXA TEST RIDER COMMENTS:

“What I liked most about the Pro Circuit pipe was that it did things that the other pipes didn’t. It was the freest-revving pipe. It was the least restrictive pipe on deceleration. It could pull a gear higher. And, it had the most top-end over-rev.”

“There is no doubt that Pro Circuit traded aggressive bottom for mid-and-up power. For faster riders, this is the best setup, since Pros don’t run down low. The mid-and-up powerband made you ride more aggressively.”

“This is the most Pro-level pipe of the test. It makes better power everywhere, except off the bottom where it was a little hesitant. Once it got into the midrange, it was one of the quickest pipes in the test.”

“It will not only pull the next highest gear, but the extra rev on top allows you to stay in that gear longer than with the other pipes.”

WHAT SKILL LEVEL IS IT BEST SUITED FOR?

Pro. The Pro Circuit pipe needs a rider who will run the engine high in the rpm range and resist shutting off. The most surprising thing was that our Novice test riders liked this pipe the most, but that is most likely because they didn’t have to shift as often and could run it in one gear longer.

WHAT ARE THE PRO CIRCUIT DYNO NUMBERS?

Here are Pro Circuit’s numbers with the stock YZ250F horsepower numbers in parentheses.

RPM……………HORSEPOWER
7000……………… 25.06 (25.06)
8000……………….29.70 (29.69)
9000……………….35.03 (34.47)
10,000…………… 37.76 (37.61)
11,000……………..39.43 (39.63)
12,000…………….40.80 (40.99)
Peak HP…………. 41.11@ 12,300 rpm
Peak torque…….. 20.52 ft/lb. @ 8700 rpm

TEST RIDER RATING OUT OF SIX

Novice……. First
Vet………….Fourth
Pro…………Third
Overall……Third

WHAT’S THE SQUAWK?

The Pro Circuit pipe comes with a spark arrestor installed. We didn’t realize this at first and had to repeat a bunch of test cycles. On the plus side, Pro Circuit includes a tube of anti-seize with each pipe and CNC-machined the pipe fittings.

WHAT’S IT COST?

$1064.95 (Ti/Ti/ carbon end cap), $809.95 (stainless/aluminum/stainless end cap).

WHOM DO I CONTACT?

www.procircuit.com or (951) 738-8050.

YOSHIMURA R&D RS-4: TOO HOT TO HANDLE

When MXA test riders were asked to fill out test forms ranking all six exhaust systems by order of preference, the Yoshimura RS-4 YZ250F pipe was on top of the majority of forms. The Yosh had the most active powerband, and it worked for every skill level from Novice to Pro. If you read shootouts to find the winner—this is it.

MXA TEST RIDER COMMENTS:

“I like this pipe the most. The Yoshimura YZ250F pipe was the most powerful across the board, and it really filled in the midrange. It was the easiest pipe to ride fast with.”

“Only the Pro Circuit pipe and Yoshimura pipe could easily pull the next gear, but of the two, the Yosh could do it easier. It had a surge in the midrange that made it feel potent.”

“The overall power was the best. It was a very forgiving pipe and allowed the rider to make mistakes and not be punished for them. It surged a little as it transitioned into the mid, but that just gave it more character.”

“Any rider of any skill level on any kind of dirt could get the most out of this pipe. It just felt extra meaty.”

“The stock pipe was good, the FMF very broad, the Pro Circuit revved quick, the HGS had horsepower, and the DR.D had pizazz, but I thought the Yosh was best.”

WHAT SKILL LEVEL IS IT BEST SUITED FOR?

Novice, Intermediate and Expert. We think this is an Expert-level exhaust system, but every skill test rider loved it.

WHAT ARE THE YOSHIMURA DYNO NUMBERS?

Here are Yoshimura’s numbers with the stock YZ250F horsepower numbers in parentheses.

RPM……………. HORSEPOWER
7000……………….. 25.16 (25.06)
8000……………….. 29.73 (29.69)
9000……………….. 34.99 (34.47)
10,000…………….. 38.10 (37.61)
11,000……………… 40.08 (39.63)
12,000…………….. 41.32 (40.99)
Peak HP…………… 41.40 @ 12,200 rpm
Peak torque……….20.44 ft/lb. @ 8900 rpm

TEST RIDER RATING OUT OF SIX

Novice….. Second
Vet……….. First
Pro…………First
Overall…..First

WHAT’S THE SQUAWK?

The Yoshimura pipe requires a nut behind the mid-pipe mount, but buyers heat shield tape and a plug.

WHAT’S IT COST?

$1045.00 (Ti/carbon/carbon end cap), $995.00 (Ti/Ti/carbon end cap), $725.00 (stainless/aluminum/carbon end cap).

WHOM DO I CONTACT?

www.yoshimura-rd.com or (800) 634-9166.

MXA’S MAP FOR YZ250F AFTERMARKET PIPES

During our initial testing of the YZ250F, the map we preferred to use with the stock exhaust system didn’t work with aftermarket pipes. After more testing, we discovered that the aftermarket pipes worked best with the stock ignition timing and slightly richer fuel mapping—typically 1, 1, 1 on the bottom and second row of the chart and 2, 2, 2 on the top row of the fuel-map graph. In colder weather, you might try 2, 2, 2 on the bottom two rows and 3, 3, 3 on the top row. It should be noted that all the aftermarket pipes from FMF, DR.D, HGS, Pro Circuit and Yoshimura are designed around the stock 0, 0, 0 maps.

MXA’S HORSEPOWER CHART FOR YZ250F AFTERMARKET PIPES