Dec 31, 1969

JustKDX would like to thank Fredette Racing Products, FMF, MX-South, MX Tech, Maier and DirtRider.Net for their support. It was their gracious support that made this article possible.


For many riders the KDX200/220 is going to be the perfect trail bike right out of the box. Its stealthy quiet, nimble, roll in a tub of warm yogurt fun and super easy to handle with a bulletproof reputation. Maybe even better than the KDXs likable trail manners though is its ability to grow with the rider’s ability. With the addition of a few simple bolt on parts and modification you can literally transform the KDX from a mild mannered trail bike into a little giant killer while its loveable character stays intact.

Many riders will personalize their bikes when they purchase them or shortly there after to best suit their individual needs. It was with this in mind that we put together Project KDX highlighting some of the most common KDX modifications and their effects on the little bike that could. Unlike many of the magazine style dream bike tests, where no money is spared to build what in the end is an unobtainable dream machine, the goal here was to keep things simple and easily obtainable /reproducible.

The Test
Over the course of the summer I gathered together a number of riders of varying abilities and gave them an opportunity to put my KDX through its paces. The goal was to gather comments from riders with a wide range of abilities and get a well-rounded impression of what to expect from a modified KDX. The test will continue through the summer of 2001 and more rider's input will be added as the year progresses.

The Bike
We used a 1998 KDX220 for this project but the results and comments would be just as applicable to any 1995 to 2001 KDX200/220. On the most part the modification were limited to simple bolt on performance and suspension parts that the average KDX owner might perform. I was lucky enough to borrow a number of parts to complement the modifications I’d already made.

When I put this bike together I kept in mind the importance of keeping it a well balanced package that would fit my riding style and ability. There was no sense spending my budget on just performance mods without addressing the suspension as well. The stock KDX suspension is capable of handing most demands a causal trail rider might ask of it. Once the engine has been modified though and the bike rode more aggressively the stock suspension's limitations become obvious. Its pretty easy to make a bike go faster but if you can't control and direct it where you want to go what's the point? The stock forks aren’t state of the art but can be made to work surprising well. Jeremy Wilkeyat MX-Tech worked his magic on the suspension which includes MX-Tech valves. The forks use a heavier rate spring than stock while the shock spring remains unchanged.

How about the engine? Its no mystery that the first step in releasing the KDXs potential is to replace the stock pipe with an aftermarket unit. Though the factory pipe is super quiet and robust it’s also very restrictive and heavy. Both Fredette Racing Products and FMF recommend the FMF Gnarly Rev pipe and an FMF silencer combination on the KDX220 and it rips. This is a real world test so yes the Project KDX bike does produce a little more noise than the stock bike. It is however still one of the quietest off road bikes around and the FMF system does a good job of keeping the volume down to a more than reasonable level while increasing power output from idle to WOT. We also installed a FRP pipe guard to keep the pipe looking new and avoid power robbing damage what seems to magically appear along the trail.

Now that the exhaust side was taken care of we directed out attention to intake side. The carburetor was modified by RB Designs to increase throttle response and improve carburetion from idle to WOT. Their modifications included boring the stock 33mm carb to 36mm, installing a divider, and modifications to the throttle valve/slide, jet screen, pilot circuit and rejet. The results are impressive to say the least with outstanding throttle response being a major highlight.

The Chassis
I’m just shy of 6’2" so to improve ergonomics the stock handlebars have been substituted with a pair of aluminum CR high bends, the bar clamps reversed and tall/stiff seat foam added. A one-piece handlebar clamp was also installed to lock everything together, improve control and reduce the chances of twisting the handlebars in the clamps. To help the rider and machine survive the riggers of off-road riding a rear disk guard was installed to protect the FRP solid rear disk. Jeff Fredette at Fredette Racing Products also supplied an FRP chain guide, FRP Hand Saver hand guards ,FRP bush deflectors, an FRP aluminum kick start lever, a Baja Designs skid plate and to maximize rider control and comfort a pair of IMS Pro Series foot pegs.

To eliminate the KDXs floppy kick-starter syndrome a trick Fredette Racing Products aluminum kick start lever was installed. It not only weighs less and looks super trick but it reduces the amount of space need to kick the bike over, a real plus in tight conditions.

The battle wary graphics were then spruced up with graphics supplied by MX South and Maier supplied an MX fender to give it an eye catching hybrid look.

If you'd like more specific information on any of the products used please visit or call our sponsors and let them know you saw their products on DirtRider.Net & JustKDX .

Their gracious support has made this project possible.

Let's Go Ride'n !

To make the test as meaningful as possible riders with a wide range of experience and ability were asked to participate and offer their opinions. As you read through their comments, keep in mind how the skill level, riding style and physique of each rider relates to your own. This article will be updated as additional riders are asked to participate and lend their opinions.

5’9" / 170 lbs/ aggressive, experienced off road riderNormal ride: Stroker modified 1997 KLX300.

I regularly ride with Jeff so he's seen and ridden my KDX at different stages of modification and is easily able to make "then" and "now" comparisons.

This package is a major improvement over stock. The bike is light feeling and very flickable with light, effortless handling.

The bike produces power everywhere and is crisp and clean over the entire rpm range. I've heard the KDX called a bottom end bike. I'd say its more of a mid to top end bike than its given credit for. The modified carb is a drastic improvement over the stock set up.

The suspension is plush and compliant. It’s more plush than my KLX and a stock TTR250 yet it’s very resistant to bottoming. The tall/stiff seat foam improves your ability to move around and makes it roomier, even for a vertically challenged guy.

Dave’s KDX is way more fun to ride, way better feeling and way better looking than it was in stock form and that’s saying a lot. If I was looking for a bike I’d have this one.

The only complains I'd have is it feels a little light in the front and the seat to tank junction is a little wide when compared to my KLX. The FMF rev pipe sticks out too much on the side compared to the FMF torque pipe.

5’9" / 185lbs/ professional MX, AA HSNormal ride: 1998 KX250

This KDX really moves. It’s got the best/ crispest throttle response of any KDX I’ve ever ridden. The suspension is a little lightly sprung for my weight and riding style but is a vast improvement over the stock suspension. Very plush and off-road appropriate.

What a difference a pipe makes on a KDX. The FMF pipe is a must have.

I really like the rear fender and graphics. Its gives it a really serious look.

5'10" 190lbs.Rode an off-road bike as a kid and picked it up again last year.
He's since introduced his son to off-road riding.
Normal Ride: 2000 TTR250

The first thing I noticed about the bike was its slim feel, it felt very light and easy to handle. The second thing was the power! It really lights up with the few mods that have been done. There's plenty of power yet its very manageable even for a novice like myself. The power wasn't over whelming but lots of fun!

The suspension felt as plush as mine and I liked the way it handles in the corners, though I felt it took a little more technique coming out of a corner than my 4 stroke. I slid around on the seat too easily compared to my TTR which made it harder for me to maneuver over things like roots and logs.

There are a ton of aftermarket parts available for the KDX and they're reasonably priced too. I wish I could find parts as easily.

The MX style rear fender and graphics really personalize the bike.

6' / 180lbs/ an experienced off road rider back from a 4 year break.
Normal ride: 2000 KDX220.

Wow is this bike fast! Honestly it was hard to believe it started off as the same machine I'm riding. It handles better, feels better and down right rips. The thing that amazed me the most is despite the extra boost it still felt very familiar and easy to ride, just like my bike. The difference in power delivery took a couple laps to get used to then I was hooked. This bike is addictively fun and easy to ride! Though there is plenty of power on hand it never felt spooky in the trees like many of the MX bikes I've ridden and rear wheel spin was still very controllable. I’ll be putting an FMF rev pipe on my wish list!

You know there was a time I didn't really mind the stock suspension and couldn't image a need to have your suspension custom tuned. Was I wrong! The handling is predictable, controllable and down right confidence inspiring. I can ride the bike faster and feel I'm in much better control than on my stock bike. I think that's what I liked the most.

I though the foot pegs looked cool right off but didn't expect them to make a whole lot of difference. I was wrong. You feel more firmly planted on the bike, more a part of the bike rather than just a rider. They are a firm foundation and feel great.

The FRP hand guards and bush deflectors are the best I've seen. I'm ordering a set for my bike. In fact I found all the FRP products to be of excellent quality. The FRP pipe guard gave me a lot of confidence when riding someone else’s bike. The fear of dinging the pipe never crossed my mind . . . . well ok it did but it was unfounded. The FRP chain guide looks very substantial. I’ll be installing one once my stock chain guide needs to be replaced. It’s easy to see the FRP products were designed by a long time KDX owner/racer. They make sense. I really like the look of the Maier rear fender.

6' 1" 168lbs. 20+ years of riding experience. Aggressive off-road rider. B-Hair Scramble.Normal Ride 1998 KDX220

The power is still smooth and predictable enough that you can find traction in the nastiest conditions but has a blast of acceleration at your fingertips when you need it. The RB Design modified carb makes the low to mid rpm power delivery even more versatile. The off idle throttle response is smooth and crisp and easily allows you to run a gear higher than you would normally. One of the biggest benefits is your ability to tackle really ugly conditions by lugging the engine and keeping wheel spin to a minimum then when you need some thrust to get you going again its right there. The carb divider offers a much more noticeable improvement than an aftermarket reed valve at lower rpms.

I've said it before and I'll say it again. . . The FMF rev pipe is a must have. It transforms how the engine delivers power and honestly makes the KDX feel like another bike. Don't make another performance mod until you've tried a pipe first. The FMF rev pipe combined with the RB Designs modified carb is my favorate combination of performance mods on either the 220 or 200.

The MX-Tech suspension sets its self apart from the previous system I used. The handling is predictable and plush enough to soak up small stuff yet does good job of handling big hits and light MX action. I use my KDX as a do it all machine and the MX-Tech team understood what I was looking for. They were able to deliver a package that's confidence inspiring whether I'm winding my way through tight wooded conditions, opening it up through a nasty whooped section or heading out for some light MX riding. Stiffening the suspension actually made the bike feel lighter. The suspension no longer blows through its travel when attacking sand whoops or trail riding at mid plus speeds.

Jeff Fredette has been riding and winning on KDXs for a long time so there's no surprise that FRP produces fit well and make sense. The FRP Hand Savers and bush guards are the nicest I've seen. The FRP chain guide is substantial and is a must have especially in the rocks which can easily persuade the stock guide. I was pumped when Jeff told me he carried an aluminum kick starter. Not only is it shorter than the stock lever, which allows you to get a good jab at the starter in really tight conditions, but its much lighter too.

The FRP pipe guard does a good job of protecting the expansion chamber. I ploughed into a cut-off stump and cringed expecting to see a mangled guard and pipe. The pipe's mounting hardware was tweaked and needed to be pulled back into place but the pipe was completely undamaged. The guard has paid for its self plenty of times and even gave me the confidence to let Mark ride my bike through the Rockies LOL. Mark was paranoid he'd damage the pipe in such rocky condition. I told him nothing it would take nothing less that a land mine to crush the pipe and off he went. Now Mark about those abrasions on my bush guards? LOL.

FRP also supplied us with a set of IMS foot pegs and a Baja Designs skid plate. Like Mark I thought the pegs looked really substantial but didn't get a full appreciation for them until things got ugly. I felt firmly planted on the bike and at the end of 4 hours of riding whoops and natural terrain MX my feet where ready for more. . . not even a whimper. The skid plate has excellent mounting hardware, it even has steal inserts in the aluminum clamps, and I'm sure it would take nothing less than a mine field to damage the frame rails or the engine's case.

Comparison Test

I thought I'd compare the test rider's bikes to mine as well so you might be able to get an idea how my KDX might compare to other off-road bikes you've been on.
1998 KX250Bill's KX was sprung for aggressive MX riding so its likely no surprise the KDX felt way more trail friendly. The KX deflected off obstacles in the woods where the KDX soaked them up. Where the KX felt punishing the KDX was relaxing and confidence inspiring. I never felt comfortable enough on the MX suspended KX to call its handling predictable in the woods. I have no doubt it works great on the track.

KX power delivery is not friendly in tight wooded conditions.

1997 KLX300
I really like the KLX. Kawasaki intended it to be the 4-stroke version of the popular KDX and they succeeded. The KLX is a turner. I've heard it called the best handling dirt bike around and I'd agree with that. My goal this summer is to make my KDX turn more like a KLX.

The KDX is a 2-stroke and the KLX a 4-stroke. To see big changes in power delivery with the KLX you need to put out some serious cash. It's much cheaper to get more power out of the KDX.

Though the KDX and KLX have close to the same seat height its easier to get your foot down on the KLX. The width of the seat behind the tank is much narrower.

I've heard people say the KLX is hard to start. Sure it takes a little more than the KDX, after all its a 4 stroke, I've never had a problem getting it to fire up on the first or second kick once shown the drill.

2000 TTR250
The TTR is electric start and stock it makes a great causal trail bike. The stock suspension its about equal to stock KDX suspension though it feels a little mushier on bigger hits and doesn't hold a line as well. That likely has more to do with the added weight than anything. Where the KDX hides its weight and feels light and flickable the TTR's weight is a little more obvious especially in sandy conditions. I don't think that's too surprising given the TTR weighs almost 40 lbs more with both bikes in stock form. Like the KLX getting more power out of the 4-stroke TTR is going to be expensive.

A stock KDX200/220 delivers noticeably more power than the TTR.

2000 KDX220 (stock)
I can't believe this is the same bike as I ride. Though it feels very familiar there is a night and day difference between my modified KDX and a stocker. You can really appreciate the modifications I've made jumping from Mark's bike to mine. Its hard to believe some suspension tuning and a few bolt on parts could make this much of a difference and I've only made a few modifications compared to what's available. I don't think I can add to anything that Marks has already said.

There are people who will worry that making their KDX faster and upgrading their suspension might detract from the fun factor. Not so. The bike is still grin till it hurts, roll in a tub of warm mud, belly laughing, eye-crossing fun.

JustKDX would like to thank Fredette Racing Products, FMF, MX-South, MX Tech, Maier and RB Designs for their support. It was their gracious support that made this article possible.
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