By now the 2003 model motocrossers have been on the market for a few months, most of you have your new rides for the up-and-coming season and we at MXracer have already burnt through several hundred gallons of race gas getting our test bikes dialed in. Now is the time of year that we freshen up our steeds and head to the track and test all of the cool goodies the aftermarket has to offer. With so many companies today producing such a wide array of performance products for your bikes, we figured we would never get a break from testing this year, because at MXracer we are dedicated to bringing you our highly regarded opinions on what the best of the best in the aftermarket has to offer. In this modern era of motocross, we are fortunate to have available to us every conceivable trick part to build our own version of a factory race bike. From graphics, seat covers, pipes and silencers, motor and suspension mods, bars and sprockets, someone could literally spend thousands of dollars building his perfect race weapon. Well, like us, most of you are probably pretty limited to what you can shell out on your ride to trick it out, so we decided to set a spending limit on our product evaluation to show you what you can get for a reasonable amount of dinero. With a $1500 budget to stick to, we tested suspensions, exhaust systems, bars, brakelines and graphics, to give you a better idea of what you can do with your bike on a budget. While it is our belief that a rider can get the most performance and enjoyment out of his or her bike if it handled well, we would prefer to have the suspension modified and tuned for the specific rider, so we enlisted Enzo Racing, Pro-Action, RG3 and Race Tech to modify our bikes with our budget in mind. Yes, sometimes even $1500 isn't enough to fully modify your suspension, but with a few simple mods you can get your bike to work much better for your own weight, skill and riding style. Now bolting a trick-looking aftermarket pipe to your bike may not make you the next supercross champ, but it will at least breathe some more life into your mill. If you have never tried an aftermarket exhaust system on your bike, you owe it to yourself to do so. You will be amazed at the performance that can be gained by ditching that ugly stocker. FMF Racing, DEP and Pro Circuit supplied us with their best exhaust systems so that we could give our valuable feedback.
KAWASAKI KX125
In 2003 Kawasaki introduced a long-awaited, completely new from the ground up KX125. Already very impressed with the KX's stock performance, we enlisted Enzo Racing to enhance the suspension components. Now, a guy can get pretty "spendy" at Enzo these days, as the growing suspension company has some of the trickest suspension parts available. Keeping our budget in mind, Enzo opted to only do a spring rate change front and rear and install carbon-fiber front fork sub tanks. These mods have a retail value of about $550, so we were quite excited to see how these items would perform without having our suspension revalved. For those of you who don't know, the Enzo Racing sub tanks are now available and aren't as expensive as they used to be. Enzo always told us the sub tanks would work great on stock suspension, but until now we had never tried them. Enzo, however, doesn't recommend using only the sub tanks, as the correct spring rate is very critical to the tanks working properly. The tanks and springs can be used as an alternative to a revalve. You're probably asking what in the heck are these sub tanks, and why we feel they are so good. What they are is two carbon-fiber bottles, one attaches to each fork via a braided line. The bottles are then fastened to the fork tube via a very trick carbon-fiber bracket. The tanks act as an air chamber, which controls the air pressure that builds up in your forks. The bottles temper the airflow, which is speed sensitive to how fast or slow the fork action is. When the fork compresses slowly, it is like having a low oil level, and when the fork compresses quickly it is like having a high oil level. So in laymen's terms, it provides a smoother, plusher ride under low-speed conditions, or over small bumps, while it makes the bottom portion of the stroke stiffer to prevent bottoming under abrupt high-speed hits, like big flat landings or larger high-speed braking bumps. The sub tanks combined with a stiffer spring rate improved the fork action tremendously over the stock units. In bone-stock form, the KX fork worked well, until our testers got very aggressive and started to hit bumps hard or try to absorb those big landings. Even compression adjustments weren't enough to keep the front forks from snapping our testers' wrists, but for a measly $550, Enzo made our stock KX perform as if it had a highly modified suspension. Fork bottoming was now nonexistent and damping was also improved in rough braking areas. The fork mods, along with a stiffer rear spring, made the KX a much more rider-friendly bike for both our heavier testers as well as our more aggressive intermediate and pro riders.
BOLT-ON POWER
DEP
We found that the DEP performance was pretty good. Off the bottom, the power was good and solid carrying a bit more punch than stock. Midrange was greatly improved, as it pulled longer and harder. The top end of the powerband was also improved carrying more revs for a longer period of time. Some of our testers felt the DEP system would possibly work better with a modified motor, but it is still night-and-day better than the stock setup.
FMF
We first bolted on the FMF Factory Fatty with the FMF Titanium Shorty silencer and realized immediately what the KX was lacking. Plain and simple, the stock pipe and silencer suck. The FMF unit has power gains everywhere and, most notably, a much stronger midrange and top-end pull. Even the long straights at Glen Helen weren't long enough to sap the rev out of our KX. This bike was now much more rider friendly.
Pro Circuit
The PC setup boasts great power delivery right off the bottom-end that pulled into good, smooth midrange. Top-end power is where this system really shines as it pulls to the moon with good usable power that carries all the overrev you need. Pro- and intermediate-level riders will love this pipe because of the top-end power.
YAMAHA YZ125
Now everybody knows Yamaha has had one of the best 125cc motocross bikes on the track for several years now, and we all know that when modified it is pretty unbelievable. In 2003, the stock YZ125 is also a very good bike, however testers complained that the stock suspension is a bit harsh over small bumps. Big hits were never much of a problem for most, and that usually would explain the rougher ride during the initial part of the suspension stroke. This was sometimes remedied by taking a few clicks of compression out of the fork and shock, but as you know if you take some away to soften up the ride over the little stuff, you had better be ready to give up a bit on the big hits. With this in mind, we enlisted the suspension-savvy staff over at Race Tech to try and remedy the harshness in our stock bike. Race Tech began by rebuilding our forks and shock and installing the Race Tech Gold Valve and changing the front and rear springs to a stiffer rate. These mods, including the Gold Valves, cost just under $700, which by today's standards is a pretty good value considering the performance that was gained. Our most experienced Yamaha tester immediately felt the differences made with the Race Tech mods. By just fine-tuning the clickers and making a fork height adjustment of 3mm lower than stock, handling and overall suspension performance were improved. Braking and cornering were much better with the new ride height, and acceleration was also improved due to traction gained by the progression of the new shock settings. The harshness in the small chop that was an issue with the stock suspension was completely eliminated and a more predictable and confidence-inspired feeling was gained.
STOPPING POWER
We also tested an aftermarket brakeline from the new upstart company Ride Engineering. Most of you have seen the trick brakelines that many of today's factory bikes have. Well, now this technology is available to you. Ride Engineering has developed a brakeline fit for most of today's applications that is a retrofit to the stock brakeline. Ride Engineering's front brakeline was installed on our YZ125 test bike, and there was a very noticeable difference in front brake performance. The lever had a firmer feel, as the line doesn't expand due to the high pressures that are put through it. The lines are also shorter, allowing you to route the line CR-style, which is the shortest route possible from the master cylinder to the caliper. This reduces the amount of line wall to expand. About 75 percent of the performance is gained by using the steel-braided line to reduce expansion and 25 percent of performance is gained by shortening the line. The Ride Engineering front brakeline kit costs only $63 and is worth every penny, as all of our testers preferred the braking performance it yielded.
BOLT-ON POWER
DEP
Off the bottom, the DEP system works a bit like the stock system, but the power quickly comes on in the midrange. With good, strong midrange over the stock setup, the DEP system carries a ton of top-end power with solid overrev. This pipe worked great when we tested out at Glen Helen, and worked best on fast outdoor-style tracks.
FMF
The FMF combo worked really well on all types of tracks. The Factory Fatty pulls superhard off the bottom making the bike a lot easier to ride on tight tracks. Midrange was improved over stock and top-end power pulls longer with good usable overrev.
Pro Circuit
After bolting up a Pro Circuit pipe and silencer, one lap was all it took to see good results. The PC setup works about the same as the stock exhaust down low in the powerband, but gives the motor strong midrange that pulls into a hard-hitting top-end with tons of overrev.
KTM 125 SX
KTM has been pulling out all of the stops over the past couple of years, especially with its 125 SX motocrosser. Each year our testing staff notices improvements that continue to push this Austrian-built bike toward the head of the pack, not only in our tests but at the races as well. One of our complaints over the years has been with the unfamiliar feeling of the suspension, as KTMs have always felt a bit different than most of the other bikes. The SX lineup seems to ride a bit high in the rear and has too soft of a fork up front, thus yielding an odd stink-bug-type of ride. This year our testers also complained about an overall harsh feeling over the rough stuff, so we had the guys at Pro-Action Suspension take a look at our KTM 125 SX and see what they could do with it. Pro-Action went to work on our bike by revalving both the front forks and the rear shock.Stock springs were used, as our setup was for our lighter test rider. A factory R&D bladder kit was also used, bringing the total cost from Pro-Action to a very reasonable $525. Pro-Action's mods turned the KTM into a totally different bike, that by the end of our initial test session we got dialed in very well. The bike became very settled in corners and the push that was present in stock form was completely eliminated. The chassis felt a bit more leveled out, which helped cure the high-speed swap that was also present in stock trim. Now with a very predictable setup, our tester was able to dial in the suspension to each track, as the clickers became very effective.
BOLT-ON POWER
FMF
In stock form, the KTM 125 has monster bottom and mid but not much overrev. The FMF SST pipe and Power Core 2 silencer shift the majority of the power from down low to the midrange and top-end, so the engine really comes to life as the rpms start to rise. The SST's additional top-end performance stretches the power and gears much further than stock, which means less shifting for the rider.
Pro Circuit
In comparison to the stock unit, the PC system sacrifices a little power down low but delivers a hard midrange hit with exceptional top-end. This pipe and silencer setup seems targeted for more advanced riders. Our faster test riders picked this combination as their first choice and felt the trade-off of bottom power for top-end and overrev was well worth it.
DEP
Since the KTM 125 has such an abundance of power in the bottom end, DEP opted to make improvements in the midrange and top-end. Like the PC setup, the DEP exhaust system doesn't make as much power down low as the stock system does, but it has big gains in mid and top-end performance. The silencer is a bit longer than the PC and FMF units and works great on fast outdoor tracks where lots of overrev is required.
SUZUKI RM125
Suzuki seemed to have hit the nail on the head a couple of years back with its all-new RM125. The bike came out of the crate in pretty close to race-ready condition. With a great stock motor package and some of the best suspension action and handling, one would be hard-pressed to find a flaw in the new mill. It seems that the last couple of versions of the RM125 may have taken a step back, as the factory has been trying to improve on what was already a great machine. Well, 2003 was no different, as the once superplush suspension took on a bit of a harsh and unpredictable feel. With the new suspension not being as good as we had experienced from the RM in the past, we contacted RG3 Suspension for a bit of help to see if we could smooth out our stock test bike. RG3 went to work by revalving the front forks and the rear shock and assembled the units with Torco suspension fluids. Revalving both ends of the RM will run you about $380, including fluids. RG3 completed our setup with one of its very trick four-post, upper triple clamps, which it left with the stock offset, a retail value of $280 totaling out at $660. Since RG3 is heavily involved with several of Suzuki's race teams, it was quite apparent that it has done its homework, as our RM was dialed right out of the truck. Our ride went from a harsh and unpredictable unit to a very plush and forgiving ride. The push that we experienced in corners with our stocker was eliminated as our RM now cornered like it was on rails. In the stock form the RM blew through the stroke which caused the harsh ride. Now the RM has a much more progressive feel to it and the rear end tracks well under acceleration.
BOLT-ON POWER
DEP
The DEP gives new meaning to bottom-end on the RM125. Strong bottom-end that transfers into a long hard-hitting midrange. This setup really changes the way the motor revs out, and worked really well on the tighter tracks where we tested, which have a lot of stop-and-go-type sections. Top-end power is strong but short, going a bit flat on top but still pulling longer and harder than the stock setup.
FMF
The FMF Factory Fatty has good, smooth bottom-end. In fact it allowed the motor to handle second gear starts much more consistently without the bog or miss of the other pipes. The good bottom end pulls straight into a long, hard solid midrange that pulls into a hard-hitting top-end with a bit more overrev.
Pro Circuit
The PC exhaust system had a ton of power to offer: decent bottom-end that made the bike easier to ride in the slow stuff and a big increase in midrange that carried over to a hard-hitting top-end with a ton more overrev than stock. This pipe combo worked well on all the tracks we tested, definitely a rider-friendly pipe for our pro testers and novice guys.
Honda CR125
After testing the CR125 in stock trim all of our test riders felt that the Honda needed the most work in the motor department. With a great handling chassis and awesome suspension in stock form we decided to build a full-blown Pro Circuit project CR125. look in the next issue of MXracer for a full test!
So what have we learned from our hours and hours of testing these fine products for you? For a rather nominal fee by today's standards, you can greatly improve the performance of your new motocross bike. Obviously the more you spend, the more performance you will gain, but for just a paycheck or two, you can make any stock bike race-ready.