Yamaha YZ125 Review – Is It The Best 125 Two-Stroke Ever?

Since there’s not much hope in the economy coming back in the near future, dirt bikers are resorting to things that will give them the best bang for their buck. As a result, 125cc two-strokes have been rising in the used market. Why? Well, it’s pretty simple, actually. First of all, you can rebuild the top-end for $150 or less, which can be done in your garage with a little mechanical motivation and patience. They are great dirt bikes to start out on for motocross, as they teach you how to control the throttle, clutch, and controls. Probably the best part about a 125 2-smoker is that they’re an absolute blast to ride! They’re light, quick, snappy, and besides, who doesn’t like the smell of race gas and pre-mix in the morning?!

Which Decade?

Yamaha hasn’t changed their 2-strokes for a while. However, this doesn’t mean it’s outdated. In fact, that’s quite the opposite, as Yamaha has been building quality 2-stroke motocross bikes for years. As long as they make them, riders continue buy them. They are often the first dirt bikes to sell in a dealer, but let’s take a look at why these bikes are so popular in the first place.

1990’s YZ two-strokes are fairly similar. In ’96 they made some changes that lasted until the end of 2001. These are still considered some of the best motocross bikes, especially the 1999 model. They are fast, reliable, and are just a great overall bike.

In 2002 the frame changed, making it lighter, narrower, and more flick-able. However, many people didn’t approve because it switched to a 5-speed transmission. 125’s have a narrow power-band as it is, and some riders just like having that extra gear.

2005 and 2006 are biggest years for the Yamaha YZ125. In ’05 they changed to an all aluminum frame, made some engine changes, as well as changing back to a 6-speed transmission.

2006 Yamaha YZ125
2006 Yamaha YZ125


Power has never really been an issue when it comes to the YZ125. In amateur ranks, these small-bore two-strokes can hold their own against 450’s with the right rider. Of course it can be harder to ride them faster, but they have the ability, and it’s extremely fun doing it. Although 125’s are known to have little to no bottom-end power, the YZ125 has always seemed to have a little more torque down low than the others in its class, making it manageable if you need to lug it in tight areas. Once you get to the mid-range you can start to feel the inner-beast come alive, especially on the later models. As soon as you hit the power-band on one of these tiddlers, you’ll know why they are so addicting. It may scare you at first if you’ve never ridden a two-stroke motocross bike, but you’ll be begging to do it again and again until there’s no more premix in the tank… Throw a pipe on this thing and get it properly ported, and you have race-ready engine on your hands (not that it isn’t with a stock engine).

In 2005, the YZ125 got a new engine and carburetor, which greatly improved the bike. It’s so crisp and fast that you don’t need to touch the bike to be competitive. Although, as the saying goes, it’s easier to make a fast bike faster… Slap a pipe on there, get it ported, run some race-gas, re-jet, and she’s ready to haul the mail!


While it’s light, fast, and flick-able, some people don’t like the way YZ125’s handle as much as other late-model 125’s. The CR125 has been at the top of its class in the handling department since the 3rd generation chassis came out in 2002. That bike handles extremely well with comfort. The 2002 and newer YZ125 are not far behind though, so don’t let that be the determining factor.

2005 was the first year of the aluminum frame, which is still claimed to be one of, if not the best 125 two-stroke made. It’s lighter, faster, handles better, and just overall rides more like a modern motocross bike.


Yamaha continues to provide top-notch suspension in their motocross bikes, and the YZ125 is no different. The older bikes from the 90s left something to be desired compared to modern mx bikes, but in the 2000’s they have some of the best suspension out of the box. Bottoming-resistance is one of the leading factors of it being at the top of its class. The ride isn’t as harsh as some of the other bikes, but like any other motocross bike, you will want to get it re-valved if you weight less than 140lbs or more more than 170lbs depending on what kind of riding you do.

In 2006, which was the last year of any major updates, the YZ125 received new SSS forks, which are considered a big upgrade. If you can find a good deal on clean ’06, buy it! If you find a nice ’05, I would definitely buy that too. For someone that’s not a pro rider, you probably won’t notice much of a difference between the two. Besides, most racers get their suspension re-valved for their weight and riding style anyway.

You Should Get A YZ125 If You:

  1. Want a light, nimble, quick bike
  2. Like mixing gas and the smell of premix
  3. Want to go back and learn the basics
  4. Like snappy power
  5. Want a dirt bike that’s cheap to maintain
  6. Want to rub it in when you beat friends on four-strokes
  7. Don’t want to make the jump all the way to a 250F
  8. Want to rebuild top-ends at home

You Shouldn’t Get A YZ125 If You:

  1. Don’t like mixing gas or the smell of premix
  2. Want a smooth and very predictable power-curve
  3. Like checking valve clearances
2001 Yamaha YZ125 2-Stroke
2001 Yamaha YZ125 2-Stroke

I’ve owned my share of YZ125’s, and they’ve all been great. The most reliable motocross bikes I’ve owned, and they’re just so much fun to ride. Of course, the newer the better, but even a 1999 YZ125 is a great bike to get started in this awesome sport. Check out my other articles on how to find deals on used dirt bikes!

-Tom Stark


KX250F & RMZ250 2004

2004 Kawasaki & Suzuki 250F

2004 RMZ250

If you’re looking at getting an older 250f, and possibly a Kawasaki or Suzuki, then you should probably consider some of this info. When these companies made their 250f, it was more like a Kawazuki 250f, because Kawasaki and Suzuki had partnered up. So most of the parts on these bikes are interchangeable. This was their first year making the 250f, so just by that you should be a little worried.

2004 KX250F

As some might expect, these bikes were not the greatest reliability-wise in 2004. Although they were fast bikes, they had an overheating problem caused by a bad/weak water-pump. Another defect these bikes had was in the valve-train that caused the valves to burn-up more quickly. These problems can get bad and scared me away from buying one of these bikes. This is not to say that these bikes do not perform. They have plenty of power, and if you really want to get one then I suggest you get a newer style complete cylinder head and get and aftermarket water-pump and impeller to fix the overheating problem. If you do that then the bike should be fine, but by the time you spend all that money on parts you could have bought a newer bike more than likely. Good luck, and remember that no matter what you ride, have fun and stay safe! Thanks

-Tom Stark


KTM 144SX – Review

When I first heard about KTM’s “New 144cc 2-stroke Motocross bike,” I didn’t think much of it, other than that it sounded really cool. I got my first taste of one at a local race, and I wasn’t even riding it! A local A rider had been riding it and was keeping up, and passing, 450 four strokes…. I knew the rider was well-experienced, but to keep up on a tight track with a small-bore 2-stroke is hard enough. After I saw the damage that this bike could do, I was determined to get my hands on one, even though they often cost more than the average Japanese bike…

2008 KTM 144SX

Let’s just say I was in love the day I bought my very own ’08 KTM 144SX. It was literally a dream come true, except for the fact that it pretty much destroyed my piggy bank. Oh well, it was worth it. If you think 2-stoke motocross bikes are dead, you better wake up and ride this bike.

Where do I start? It’s not a Japanese bike, which has thrown people off because they have a “distinct” feel and layout to their bikes, while KTM has a different set up. It really did not take long to adjust to this all-new bike, and in fact, it only took a couple rides for the 144SX to feel like home. That usually doesn’t happen on a big bike, considering I am only 5’6” (168cm). The ride height was a bit high for me, but I could easily adjust the sag settings. Overall it wasn’t too far off from the modern ‘Jap’ bikes that I’m used to.

View The VHoldR ContourHD Camera Here


KTM’s suspension hasn’t been up to par in the past. After riding the 2008 144SX I can tell they put a lot of work into this department. It was a little on the stiff side for me, but I only weight 135-140lbs. I don’t think I ever bottomed out, even on the harshest landings, so that’s a plus! It didn’t do anything I didn’t want it to. Braking bumps were not a problem, and if you want to go through a rut, it’ll do that too without making you want to stand up. The only thing I really needed to do to make the suspension set-up for my racing is a few clicker adjustments and possibly softer springs, otherwise it worked great.


I couldn’t help but notice how light-weight this 144SX is when I lifted it up. This explains why it’s so easy to maneuver the bike in almost any situation. While riding this bike it reminded me of the CR125 I had because it handled so well. If you want to go somewhere, just point and it will do it. It can hit an inside rut, rail an outside berm, and scream down hills without hesitation. KTM knew what they were doing when they built this bike.


And now to the part that you’ve probably been waiting for….. No, I KNOW you’ve been waiting for. It’s no secret that KTM wins this category on almost every bike they make, and being a big bore from the factory, the KTM 144SX/150SX on the top of many two-stroke lovers lists.

Let’s just say that you shouldn’t need to modify the engine…… or anything that can give you more power. If you think you need a faster bike then you’re either a pro rider, or….. well….. you like looking at numbers. Now lets get to the point. Bottom-end power is nothing to brag about, but 125’s aren’t meant to be lugged around anyway. You’ll know when it hits the mid-range, because that’s when the 144SX starts to wake up. Whack that throttle wide open and hold on for the ride of your life. You’ll know when you get on the pipe because the power is unlike most 125’s.

It’s not unrideable like some 2 strokes, but it has enough power to do what ever you want, and plenty of it. The power-band is a little peaky combined with its tall gearing, and over-rev is great if you don’t want to shift into the next gear right away. I was simply amazed at the pure horsepower it made, and how much power it put to the ground. There was a dyno test with this bike and KTM 250F, and the 144SX took home the trophy for peak horsepower, as well as being very close to putting out the same amount of torque. All I can say is, if you keep this sucker on the pipe, get out of the way because there’s not much that can stop this bike.

2008 KTM 144SX

Additional Notes…

Aside from having the best engine in its class, excellent handling, and great suspension, it’s still not “THE BIKE” to get for everyone. It does have its drawbacks, but then again, what bike doesn’t? I knew going in that buying an Austrian bike would cost a little more. So, when it comes to rebuilding these KTM’s, especially a 144SX, parts aren’t always as easy and cheap to find as it would be for a YZ125.

There are other things about the KTM 144/150SX that make it unique; it’s really easy to work on some parts of the bike, but others you just ask yourself, “Why in the world did KTM do that?!?!”

All in all this is an excellent race bike, and can be used by a young rider coming up from 85’s that still wants a 2-stroke, an A class rider that likes a 2-stroke motocross bike to whip around on, or a vet rider that’s looking to re-live the glory days on a really fast and lightweight dirt bike.

-Tom Stark

Click Here To Sign The Petition To Allow 144cc 2-strokes To Run In The 250 Lites Class and 300cc 2-Strokes To Run In The 450 Class In AMA Professional Racing!!

The Free Dictionary: bike definition: ”’chiefly Scottish”’ a nest of wild bees, wasps, or hornets.

2003 Kawasaki KLX300 Review – Rival of The Honda XR

It’s always been known that Honda XR’s are pretty much bomb-proof trail bikes. It would seriously take some long and hard abuse to kill one of those things. But in this day and age, the XR is becoming more of an out-dated piece of machinery compared to the modern high-tech dirt bikes. Kawasaki has been making the liquid-cooled KLX300R trail bike since 1997, but in 2003 it got a nice face-lift. The KLX300 is in the same class as Honda’s XR250R, but even with the extra displacement, it will still be hard to beat the mighty, air-cooled XR.

More power is better, but it won’t do you much without having good handling, suspension, ergonomics, and reliability, as well as light-weight. Combining the five would give you the best trail bike possible; extra horsepower is a bonus in my book. But since riders aren’t all the same size, shape, and skill, it’s hard to make the best overall bike possible. Kawasaki succeeded in some areas, yet didn’t quite meet the standards in others when building the KLX300.

2003 Kawasaki KLX300R

One of the first things I noticed about this bike is that it has mx-style inverted forks, unlike its XR competitor. This makes it feel and ride more like a motocross bike, but with really plush springs.

Handling is surprisingly good on the KLX300. It’s easy to turn and will go where you want it to. It does get a little twitchy going fast over rough ground, but it handled every terrain I rode on excellently. The bike doesn’t feel too bulky, and the seat is low and comfortable; perfect for my short frame and legs. It’s easy to squeeze your legs right up against the frame and let the bike do most of the work. Although, hanging on with your arms is awkward at first. I’m not really sure what Kawasaki was trying to do when they made the handlebars. They are really wide, low, and weak. Unless you’re an odd-ball that likes the fit of the bars, they would be the first thing to go.

Although the KLX300R has motocross-style suspension, it does not perform exactly like it. It’s a smaller and cheaper version of it. You can’t tune the forks and shock as you would be able to on a race bike. With that said, many KLX owners have swapped out the stock forks for a pair from an older KX250 (there may be a future article on how to do this if I get enough responses). With some adjusting of what clickers I had, the bike was finally riding like it should. I’m a light rider, and I had to have the clickers almost all the way in for it to be stiff enough. I do occasionally jump the bike, but its main use was riding single track trails, so the suspension couldn’t be too harsh. If you weigh over 150 lbs (68 kg) you’ll probably need to get stiffer springs, and it will be well worth it once the bike is set-up the way you want.

Weighing in at 231 lbs makes it the lightest bike in its class. This is a huge bonus because you definitely feel the extra weight on heavier bikes when shifting around on the trails, or when you are picking the bike up after a spill. It’s not as light as a 2-stroke, but definitely lighter than a 450cc off-road dirt bike.

As far as reliability goes, the KLX300 is as close to bullet-proof as you can get. There were a couple problems in the engine, but the main one was the cam/timing chain tensioner. After a few thousand miles or so of wear it would get caulked down, causing the chain to be loose and make noise. Many new KLX owners get frightened by this because it often makes a loud knocking noise. The same thing happened to my 300R, and I thought for sure it was piston-slap since the noise was really loud and would go away once the bike was hot. I eventually bought a new tensioner just for the sake of it, and when I was taking out the original one, it didn’t even look crooked or broken. I was hoping that it would still somehow be the problem, and I was right. I started up the bike with the new one in and it purred like a kitten.

Other that, I haven’t a problem with this bike. As long as you change the oil/filter, clean the air filter, lube chain, etc. when you should, this bike will last a long time. Check the valves and timing chain every year or two, as well to make sure they aren’t worn or have moved.

2003 Kawasaki KLX300R

Lastly, when I said power was just a bonus on a trail bike, I didn’t exactly mean that power doesn’t matter, because it does…. From some help of the extra 50cc’s, the KLX300 is the most powerful in its class. More horsepower and torque than the XR250R and DR250. Don’t get too excited, though, because the 24 ponies it puts out makes a very smooth and linear power curve. This is mainly thanks to the Keihin CVK 34mm constant velocity carburetor. It uses the pull of vacuum to move the slide up, which takes away any “snap” the bike would have had. It simply robs torque and horsepower that this bike could’ve had.

On the flip-side, having a very mellow power-band makes the bike extremely easy to use and allows it to putt up steep hills with ease. You shouldn’t have trouble going through tight trails, no matter the conditions, because it will put what power it has to the ground with a good rear tire on.

All-in-all, there are ups and downs to the Kawasaki KLX300R, but most of the flaws are easily fixable. I wouldn’t mind getting another one of these in the future for going on long trail rides. So, let’s review what this bike has to offer…

What’s good?

  • Lightest four-stroke in its class
  • Very easy to ride
  • Motocross-style features (inverted forks, liquid-cooling)
  • Smooth power-curve to putt up hills
  • Sips on gas
  • Reliable
  • 36 in. seat height
  • Very quiet for riding in people-dense areas

What’s not?

  • No electric-start
  • No hot-start (often floods if you stall, making it harder to start)
  • Low, wide, and weak handle bars
  • Inverted forks are not fully-adjustable
  • Throttle requires you to turn it too far
  • Engine is choked up with the small carb. and exhaust

Haul your KLX300 with an Aluminum Motorcycle Carrier.

If you have any questions or concerns, feel free to comment!

P.S. Stay tuned for a future article or two on how to hop-up your KLX300 for cheap!…

-Tom Stark

250cc Motocross Two or Four Stroke?

250cc 2-stroke vs. 250cc 4-stroke

If you’re looking to get into racing motocross at AMA sanctioned tracks and are wondering which bike to buy for the 250cc class, then pay attention. Although the four-strokes have pretty much taken over the motocross market lately, it seems that there are a lot of people trying to bring back the two-strokes, and it seems to be working. AMA made it legal so that a 250cc two-stroke can run in the same class as a 250cc four-stroke. Now, the first reaction I had when I heard of this was without doubt to pick the two-stroke. I looked into it a little bit more and came up with this….

250cc Four-Stroke

YZ250F 4-Stroke

Now most people would think that a four stroke with the same displacement as a two-stroke would not have a chance, and that is why the AMA originally allowed the four strokes to run a bigger engine in 1998. This isn’t the case, due to the fact that companies have put so much more money and effort into making the modern four-strokes extremely high-performance. Some riders that do not like the two-strokes snappy power will often stick to the four-stroke 250 just because they like their broad and easy-to-ride power-band. A 250 two-stroke may have more peak power, but when the day gets long and the track starts to get really rough, that’s when the four-stroke starts to shine. Due to the tractability in rough and slick conditions, the four-stroke will be easier to ride faster late in the day. That doesn’t mean it will be faster than a two-stroke though…

250cc Two-Stroke

Two-strokes are fun to ride because they have a bigger top-end “hit” compared to the four-stroke. If you keep the two-stroke on the pipe then it will definitely be faster than the 250F, as long as the conditions aren’t too rough. For those of you that want more, snappy power, and a lower center of gravity, then go with the two-stroke. It may not always have the traction that a four-stroke has in rough or slick track conditions, but the horsepower makes up for it.

YZ250 2-Stroke

So Which Bike??

After reading the info on each bike you would probably guess that the two-stroke is the better bike for AMA racing, and my answer for that would be, “Yes.” Clearly, it’s a faster bike if the track is in good shape, it handles better because it has a lower center of gravity and is a 2 stroke, it has a lighter front-end allowing you to skim over whoops and bumps, and it smells good. But I will say that if you are a four-stroke guy that doesn’t like the snappy-feeling power-band on the two-stroke, then you will be fine on a 250F. The 250F is by no means slow, and any good rider should be able to win on it. My choice would be to ride the 250 two-stroke though because it’s faster, and it’s a new rule that I would take advantage of. Good luck, and no matter what stroke you ride, have fun!!

-Tom Stark