2013 Yamaha YZ250F

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New dirt bikes come out every year, but that doesn’t mean riders are buying new machines every 12 months. No, for various reasons, riders will often keep a motorcycle for two, three, or four seasons. Heck, a die-hard might never get rid of a certain bike. Whether they simply can’t afford new machinery or have become particularly attached to a certain ride, the fact remains: motocross bikes need to be able to take lickin’ and keep on keepin’ on…wait that’s not how the phrase goes. Well, you know what I mean, and some equipment handles the test of time a bit better than others.

Now, one year probably didn’t cause even the slightest hint of degradation in the great pyramids of Giza (unless the aliens from Independence Day made a surprise visit), but the same time span for a motocross bike can encompass its entire life cycle. However, most bikes will last much longer than that, and even though the 2014 Yamaha YZ250F is set to be released shortly, there will be thousands of 2010-2013 YZ250Fs floating around motocross tracks all over the world for years to come. Here are a few simple modifications we made to our small-bore Yamaha over the year that we found were helpful with overall performance.

Power Punch

The 2013 YZ250F was the last full-sized carbureted four-stroke motocross bike to come from the five major OEMs. In fact, the Yamaha has been the sole carbureted bike since 2011, and while this was a disadvantage in some ways, it was also helpful in others. The YZ250F’s motor remained relatively similar for the better part of a decade. While other companies jumped around to different configurations, Yamaha, and more importantly, aftermarket companies and engine tuners had years to figure out the best settings for the blue engine.

While the power output of the 250cc motor is fine, a few little changes made big improvements. The stock YZ-F has a tendency to bog slightly when landing from bigger jumps and during abrupt G-outs. Moto Tassinari’s popular air boot replacement, the AIR4ORCE, did wonders for this issue, virtually eliminating bog by increasing the speed of airflow through the boot and into the carburetor. The different velocity stacks included with the AIR4ORCE allow the rider to tune the intake curve to their preferences. I found that the longer stack, designed to improve bottom end hit, was the most effective in removing bog.

Also in the intake department, we installed a Loud Mouth MX Intake System. The billet aluminum unit replaces the stock air filter mount and removes the backfire screen. The opening is an unobstructed circle, utilizing a unique air filter that is intended to allow more direct airflow into the air boot. The combination of the two intake systems, the Moto Tassinari AIR4FORCE and LoudMouth MX, completely changed the bottom end characteristics of the YZ250F. Bogging became a thing of the past.

The last intake addition we made was simply installing a Works Connection Fuel Mixture Screw in the carburetor. The ability to make quick adjustments to the air/fuel mixture not only saves time, but allows more accurate and incremental adjustments, even throughout a single ride day.

On the other end of the engine, Pro Circuit set us up with a T-5 Exhaust System. The T-5 pipe and RC-4 header made a night & day difference when compared to the stock unit. Not only does the Pro Circuit system add a nice throaty note compared to the very muffled stock system, it drastically helps increases the bottom end hit.

Whether coming out of tight rutted turns or hitting quick seat bounce jumps, it is much easier to stay within the meat of the power without needing to dab the clutch. While midrange power remained about the same, up top the T-5 system allowed the power to continue climbing beyond the RPM range where the stock system normally falls flat.

Lugging my not-meant-for-250Fs body around and overusing the clutch to get through tighter turns, there was no way the stock clutch would last. To Yamaha’s credit, the stock steel plates and fibers lasted far longer than I expected they would, but eventually slippage became too much to ignore and it was time for replacement. Tuf Racing has a complete clutch kit that includes fibers, steels, and springs, and needless to say this brought that more positive grab that one expects from a fresh clutch.

One of the reasons the stock clutch plates lasted so long probably had to do with going up a couple of teeth on the rear sprocket, again to increase bottom end hit (are you noticing a theme here?). Switching over to Sunstar’s chain and sprocket combo (Works Triplestar Rear Sprocket, 520 MXR1 Motocross Racing Chain, and Steel Countershaft Sprocket) with a 52-tooth rear chain wheel, was the final piece in the bottom-end-hit puzzle.

Of course, the look and durability of the sprockets and chain improved as well, but the main goal was to get a little more pop and pizazz out of the stock motor package. I would say that, between the Moto Tassinari AIR4ORCE, Loud Mouth MX Intake System, Pro Circuit T-5 Exhaust System, and Sunstar chain and sprocket combo…mission accomplished. There are endless motor modifications that can be done to any motorcycle, but we wanted to see how we could liven up the 2013 YZ250F affordably and with basic bolt-on options.

Can the carbureted YZ250F compete with the EFI armada? Just ask Cooper Webb, Jeremy Martin, Kyle Cunningham, Dean Ferris, or…well you get the idea. All of these guys had excellent 2013 seasons and they all did it on bikes that started out as stock YZ250Fs, just like our test bike.

Handling

If there is any single characteristic that stands out the most on the 2013 Yamaha, it would have to be stability. Like a well-behaved child, the bike simply refuses to get out of line even on the roughest of straightaways and has surprised me at times with its ability to remain aligned when heading into rough braking chop. Add to this what I still believe to be some of the best stock suspension on the market, and the YZ250F was definitely one of my favorite 2013 bikes for handling.

With that said, while the stock suspension was able to handle my weight and ability for a bit, the springs and fluid began to show signs of wear after some good usage. Eventually, the bike got down to the last couple of compression clickers on the forks, meaning it was time for a refresh. Yamaha’s have come with Kayaba suspension for years, so why not go to the main KYB guru in the U.S., enzo suspension. While enzo handles and oversees suspension duties for some of the top racers in the world, they also take care of regular Schmoes too, and in this case, all we needed was the regular Schmoe treatment. Aside from simply refreshing the seals and fluids, enzo swapped out to stiffer spring rates in both the fork and shock to accommodate for my non-jockey height and weight.

I am always amazed at the difference of riding with a bike that is properly suspended for my own ability, height, etc. versus stock machinery. If a bike is not supporting your weight, speed, and aggression, it can significantly slow you down, and even make riding more dangerous than it already is. From the moment I hopped on the new enzo modifications, I immediately began pushing harder on the track than I had in months for no other reason than that I felt like the bike wanted to be pushed…rather than screaming for help every time I took to the air.

In Control

I feel right at home with the stock Yamaha bars and bend. While we did eventually switch over to the ODI Control Flex Technology (CFT) handlebars, it was not a necessary change. However, I am glad we made the switch because, as I mentioned in a recent review of the CFT bars, they are very forgiving and have saved my wrists on more than one occasion.

Along with the bars, we also threw the new, second generation ODI Lock On Grips. I say “threw” because with the Lock Ons, there is no need for glue. The throttle-side grip is vulcanized onto a replacement throttle tube, while the clutch-side grip utilizes a clamp on the inside of the rubber flange that is tightened with a small Allen wrench. Yep, nifty and very easy to replace or remove should the need arise.

One thing that has always bothered me with carbureted four-strokes is the hot start lever. Not so much its existence, just the location: usually somewhere on the clutch perch. I always felt that having the extra lever in that area was beckoning for a mistake while riding…just one more thing to worry about, and a rider does not need distractions. This is why we went with the Zeta Rotating Barclamp with a hot start lever, allowing the cable to be rerouted to the throttle side. The Zeta unit replaces stock clamp, can rotate if need be in a crash, and keeps the hot start lever out of the way while riding.

On the clutch side, we used Zeta’s beautifully machined Pivot Perch CP, an adjustable clutch lever with two different leverage ratios to choose from, a pivot bearing, on-the-fly tension adjuster, and the ability to flex out of the way in the event of a spill. Not only does the Pivot Perch CP have bling, it works too.

For traction, Jay Clark at Dunlop slapped on some Geomax MX51 tires. If you have never used the MX51 series, they are a very well-rounded tire that can handle a broad range of conditions, offer predictable turning charateristcs, and wear very evenly.

Finally, the stock 2013 Yamaha four-strokes were some of the better looking stock bikes I have seen in a few years. With the black rims, white and blue plastics, and blue and black seat cover, I had more than one passerby comment on how good the YZ250F looked. Of course, we had to throw our own little flare onto the bike with some Factory Effex graphics to round out our yearlong test ride.

If you already have a 2013 YZ250F or come across a used one, you may find that some of these simple mods could help the performance of your machine as well. Now bring on 2014!

For more information on all of the products used on this bike check out:

Moto Tassinari - mototassinari.com

Loud Mouth MX - loudmouthmx.com

Tuf Racing - ufoplasticusa.com/index.php?tuf=1

Pro Circuit - procircuit.com

Zeta Racing - zeta-racing.com

Works Connection - worksconnection.com

Factory Effex - factoryeffex.com

Sunstar Chains and Sprocket - sunstar-mc.com

Dunlop - dunlopmotorcycle.com

enzo racing - enzoracing.com

-Bayo Olukotun