Yamaha 125 Four Stroke 2015 Manual
Introduction. Yamaha has faith and confidence in it's YZ two-stroke. Still selling and offering a more affordable motocross option.
Yamaha 125 Four Stroke For Sale
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For a bike that has changed so little over the years, the new look is huge. In 2005 the YZ125 received a major change to the aluminum frame but beyond that Yamaha has only made minimal changes to this model. Fortunately, for all you 125 fans, Yamaha has finally rejuvenated the YZ125 for 2015. The little YZ’s new bodywork is attacking and modern. The YZ125 was intended to be the world’s best 125, but what is the purpose of that now? With the 125cc class turning into what we now know as the 250cc four-stroke or Lites on the professional level, does it seem odd a manufacturer would continue to put so much effort into updating a bike that has no professional classification?
Well, the YZ125‘s most obvious and often overlooked purpose is to serve as a great transition vehicle for young teenage whiper-snappers coming off 85cc machines that are not ready for the ever progressing 250 four-stroke motocrossers. Most amateur motocross organizations still continue to offer 125 class too. But the biggest reason we must not forget is that 125s are just down right FUN! Changes.
New plastics for a fresh look. Small upgrades to suspension and brake parts to match the YZ four-strokes. The YZ125 has a quite a few changes for 2015, if you are going by the track record of the YZ over the last few years. For the most part the main chassis and the engine are truthfully unchanged. The most noticeable is the more modern looking plastic including the radiator shrouds, front and rear fenders, number plates and fork guards. The airbox is also all-new to match.
The YZ gets a new rear disc protector and rear brake caliper protector. The rear sprocket is slightly altered too. Yamaha updated the fork to the latest generation KYB Speed-Sensitive fork just like their four-stroke bikes.
The clutch lever perch has option to adjust for the riders liking and size of hands and it is quick-adjust on the cable. New Dunlop MX52 tires were chosen for what Yamaha claims is superior traction and durability. Even the titanium footpegs are wider for your comfort.
Power. A long and plentiful powerband for such a small motor with a bottom and mid-range emphasis.
Top end is decent but not excellent. Shifting a little earlier is better. Smooth shifting and an excellent clutch feel. Since I am a four-stroke rider I am sensitive to low-end torque and do not have a piss-revving riding style that you might think you need to ride a 125cc two-stroke, I wasn't sure about riding a 125. The YZ 125 really surprised me from my first lap. I could rely on the bottom end power to keep my corner speed up. It pulls from a pretty low RPM right out of inside ruts and puts down enough meat to clear most gaps on today’s jump infested tracks.
To complement the strong bottom power, the engine transitions equally as strong through the mid-range-there is not really a step in the power, just more pulling as the R’s build. The softest part of the motor’s spread is the top-end. It gradually signs off and flattens out, but this isn't anything like the rev-limiter cutting in on a four-stroke. This was most apparent on high speed straights where I would need to grab an additional gear or on some jump takeoffs for our larger test riders who needed to make a quick shift.
The sign-off is gradual and we also learned that getting more up top was as easy as installing different aftermarket pipes and mufflers. The length of the pull on the YZ is a little short when compared to a four-stroke as well. You definitely have to shift it more and pay attention to keeping it in the right gear.
There is no lugging this bike if you want to go fast. The use of a powervalve that alters the exhaust port height and the volume of the exhaust tract surely helps the bottom and mid-range but for the most part this bike is ridden at high RPMs where the valve is also wide-open. And gearing can play a large roll in having the bike set up for you. Especially for the heavier riders, sometimes we felt adding a tooth to the rear sprocket, depending in the track, could have the bike pulling better at the right times. The clutch pull was light and easy on the rider’s left hand.
Sometimes deep into the moto it was necessary to roll the clutch quick-adjuster forward, as the clutch got hot from abuse. Shifting was positive; selecting the proper gear was effortless.
Using only minor clutch slipping to keep it in the meat of the power, I could even short shift at specific times. The jetting on the YZ is very crisp to point of perfection when compared to the way older two-strokes are described. Or even compared to my friend’s bikes that I have ridden, they really should ride the Yamaha to see what a bike should be jetted like. The muffler does a good job of keeping the sound down and like all two-strokes the sound does not carry as far as on the four-strokes.And does this bike ever start easy.
Just touch the kick-starter and it comes to life. Just remember to give it a little gas when you kick. Suspension. KYB's excellent SSS front fork suits a wide range of riders and draws few complaints. For suspension around since 2006, it is still as good as anything else these days. The clickers make precise changes and they work.
Yamaha sets up their stock suspension setting for intermediate riders that weigh of around 165 pounds, maybe less. I’m only 110 pounds so the suspension was overall too stiff for me. The KYB rear shock can be fully adjusted; there is a steel spring (at one time Yamaha had titanium springs standard) and a Kashima coating on the internals reducing heat and friction. We set the race sag on the rear shock at 99 millimeters, which is all we could get while keeping some preload on the spring. I would truthfully need softer springs front and rear. Overall it worked well on the motocross tracks, I felt confident in ruts and jumps. Being on the stiffer side it kicked me around when hitting deep holes and kicky whoops.
The shock was initially stiff for off-road riding but soaked up any big impacts. The 125’s fork works well on just about anything even though it was set up for a heavier rider. Despite the suspension being over sprung I still managed to bottom on occasion. Heavier riders were also pretty impressed with the suspension being able to work for them. With just a setting of spring preload we had guys near the 200-pound range riding and happy on the bike, but also needing heavier springs really. No matter the rider we could get a really good setting through the clickers which make noticeable changes just how we have become use to.
Chassis - Handling. This is the lightest feeling full-sized motocross bike ever.
Just think about hitting a line and they YZ125 will obey. Easy to throw around in the air. The Yamaha is one of the lightest full-sized bikes on the market at 214 pounds full of fuel. You feel it every time you move the bike around and especially when you go to put it on the stand. On the track this light feel is amazing, especially coming off a four-stroke that is usually at least 20-pounds heavier. The YZ feels flickable in the air and it is almost like you can move it from underneath you with your feet. The front of the bike is easy to lift and the whole time it feels like the bike is “dancing” underneath you.
It may not really feel as planted or stuck to the ground as my four-stroke, especially on choppy hard-packed ground, but the bike didn't do anything funny. And here opening up the compression on the shock, both high and low-speed compression can settle it right down. On the YZ125 you will make up time by late braking and going into and through the turns faster since the bike is so light feeling and easy to recover from if you make a mistake. Sticking it into a line that you might miss on a heavier bike is easier if you use muscles, there is less bike to fight. Where you will lose time to a four-stroke is just exiting the turn or in places where you have to make an extra shift right away. If you are in the meat of the power the YZ is not much slower than a 250cc four-stroke, it is just that meat of power does not last as long.
The ride is very neutral and the Yamaha feels balanced front to rear. The rider compartment on the YZ is very open and comfortable. I was able to move around on the bike as I wished getting the bike to turn excellent by sitting forward. The handlebar clamp is two-position adjustable and we always ran ours in the more forward position. I was not a big fan of the front brake, It did not feel too confident inspiring and seemed to be a little weak when coming into a corner hot, but all it took was a little bleeding and the power came right back. Since the bike is so light the brakes are plenty strong.
The rear has good feel and it needs to since the two-stroke does not have the compression braking of the four-stroke and more rear brake use is necessary. I also enjoyed the position, grip and comfort of the wide, lightweight titanium footpegs. A few of our riders were not a fans of the Dunlop MX52’s, especially on the softer tracks we rode at, but they were an excellent tire choice for the California hard pack clay and for durability. You will be amazed at how long things like tires, chains and sprockets last on a 125 compared to bigger bikes. Conclusion.
One of the funnest bikes you can ride. The handling and suspension are as good as any bike out there. In a world where four-strokes are floating around the $10,000 mark, the $6390 YZ125 is looking good. Easy to maintain and parts are reasonable.
As a four-stroke racer since the time I was on an 85c-and that was a few years ago- Yamaha’s 2015 YZ125 impressed me. The engine’s power character made this YZ a ton of fun to ride.
Being able to hold a bike wide-open with confidence and not being sacred of the power was an exhilarating feeling. Since Yamaha did a nice job freshening up the style it makes this bike look like the ripper it is. There wasn't one test rider who didn't enjoy their time on the YZ125, most didn't want to get off. Everyone commented that they felt like they were riding fast even if they may have been going a little slower than on a larger displacement bike. And most said they didn't get nearly as tired riding the YZ125. I wouldn't mind owning one myself. All I would need to do is tune up the suspension to make it work for my size and ability. Star raider's motorcycle.
From kids bumping up to big bikes (the right way) to guys that just want to hold the throttle wide, this is a bike that seems to slip off the radar. We are seeing a lot more two-strokes at the tracks since they are less expensive to run and easier to work on for the average guy.
All it takes is a little extra mixing of oil in your gas to give you the pre-mix you need. The price is easily a couple thousand dollars less than some of the 250Fs out there so you really have to consider that too.