Two-Strokes Are Still A Priority At KTM
Photos By Simon Cudby
Pointing out that the power-to-weight ratio, the lower cost and the simplicity of ownership are known advantages of the two-stroke motorcycle, The Austrian brand showed their commitment by bringing an all-new KTM 125 and 150SX to the table for 2016. With a unique engine architecture and mated to the very same frame (with some fitting modifications via the unique lower cradle) that all the four-stroke SX bikes receive this small-bore two-stroke is looking to the future.
The 125 and 150SX displacements both ride atop the same engne cases using the exact same crank and differ only in bore by 4mm, 54mm for the 125 and 58mm for the 150. The carburetors are the same 38mm Keihin with a different needle providing a very crisp power delivery. The pipes are also claimed to be unique to each model. There are a number of reasons for the more vertical placement and the raising of the engine shafts as well as the shrinking of the circular items in the engine to make it more compact as well as a lot lighter. Dropping 4.4-pounds from the previous model on a 125cc engine is pretty substantial.
The light weight feeling is in every one of the new SX riding on the revised chassis, but the 125/150 feels absolutely feathery. They make a 250F feel porky and heavy side-to-side, even the light-feeling KTM 250SX-F we rode on the same track on the same day. Yet for some reason the chassis has this light bike feeling much more planted to the ground than we remember, though the saturated ground at the test location could also have been playing to this feeling. The chassis is compact yet very roomy and was keeping both small and large riders happy, especially getting forward into the turns. Though the suspension was set up for riders in the 130-150-pound range yet we were able to get it working and staying balanced for even riders in the 175-pound range. Some felt the suspension was a little soft, especially for pilots not use to the comparative lack of torque compared to a four-stroke when hitting bumps or landing from jumps. If there was an area that really stood out on the 125/150 it would have to be the turning. For a bike that does not have any compression braking helping the front end stick going into a turn, the SX was amazing and continues that way as you get on the throttle.
As far as the power goes, the typical and familiar long and smooth power pull of the KTM has not changed. There is a claimed increase in power over the last year’s bikes and we will agree that both 125 and 150 felt at least as strong as any stock 125 or 150 we have ridden. Of note is the ease at which the powervalve can be adjusted and it makes a difference in the way the bike picks up when under a heavy load. The new design has the side exhaust sub-ports opening at a different and quicker ratio albeit later in comparison to the main powervalve flap. The delivery feels a little bit stronger but with less flywheel effect so screaming it really pays off, on either 125 or 150. Most impressive is that the 150 has the same length of pull, especially in the high RPM and into overrev that the 125 was known for. The 150 has enough power that a lighter rider could easily compete against 250F riders provided they are good with the shifting and keeping the KTM on the pipe and in the peak power. Those use to the Yamaha YZ125 style of power will still be wanting a little more off the bottom.
KTM has really made a lot of 125 riders and future owners happy with the release of this bike. And they are likely not done even yet, as there is the mounting bosses on the engine for the addition of an electric starter (they will need to have a new side cover to contain the Bendix gear and modify the ignition and flywheel) in the future. And remember, as much power as an electric starter needs, so does the necessities for EFI too. But never the less, if you want the latest in two-stroke power and handling, this is it.
125 SX SPECIFICATIONS
Engine Type: Single Cylinder, 2-Stroke
Displacement: 124.8 cc
Bore / Stroke: 54.0 / 54.5 mm
Starter: Kickstarter
Transmission: 6 Gears
Fuel System: Keihin PWK 38S AG Carburetor
Lubrication: Premix 40:1
Primary Ratio: 23:73
Final Drive: 13:50
Cooling: Liquid Cooling
Clutch: Wet Multi-Disc Clutch, Brembo Hydraulics
Ignition: Kokusan
Frame: Central Double-Cradle Type 25CrMo4 Steel
Subframe: Aluminum
Handlebar: Neken, Aluminum Ø 28/22mm
Front Suspension: WP Suspension USD 4860 MXMA 4CS
Rear Suspension: WP Monoshock 5018 BAVP DCC with Linkage
Suspension Travel Front/Rear: 300 mm/11.81 in; 300 mm/11.81 in
Front/Rear Brakes: Disc Brake 260 mm/10.24 in; 220 mm/8.66 in
Front/Rear Rims: 1.60x 21, 2.15 x 19 Excel
Front/Rear Tires: 80/100-21”; 100/90-19” Dunlop MX32
Chain: 5/8 x 1/4 in
Silencer: Aluminum
Steering Head Angle: 26.1º
Triple Clamp Offset: 22 mm
Wheelbase: 1,485mm ± 10 mm / 58.5 ± 0.4 in
Ground Clearance: 375mm / 14.8 in
Seat Height: 960 mm / 37.8 in
Tank Capacity, Approx: 7.2L / 1.9 ga
Weight (without fuel), Approx: 89.2 kg / 196.7 lbs
150 SX SPECIFICATIONS
Engine Type: Single Cylinder, 2-Stroke
Displacement: 143.99 cc
Bore/Stroke: 58/54.5 mm
Starter: Kickstarter
Transmission: 6 Gears
Fuel System: Keihin PWK 38S AG Carburetor
Lubrication: Premix 40:1
Primary Ratio: 23:73
Final Drive: 13:50
Cooling: Liquid Cooling
Clutch: Wet Multi-Disc Clutch, Brembo Hydraulics
Ignition: Kokusan
Frame: Central Double-Cradle Type 25CrMo4 Steel
Subframe: Aluminum
Handlebar: Neken, Aluminum Ø 28/22mm
Front Suspension: WP Suspension USD 4860 MXMA 4CS
Rear Suspension: WP Monoshock 5018 BAVP DCC with Linkage
Suspension Travel Front/Rear: 300 mm/11.81 in; 300 mm/11.81 in
Front/Rear Brakes: Disc Brake 260 mm/10.24 in; 220 mm/8.66 in
Front/Rear Rims: 1.60x 21, 2.15 x 19 Excel
Front/Rear Tires: 80/100-21”; 100/90-19” Dunlop MX32
Chain: 5/8 x 1/4 in
Silencer: Aluminum
Steering Head Angle: 26.1º
Triple Clamp Offset: 22 mm
Wheelbase: 1,485mm ± 10 mm / 58.5 ± 0.4 in
Ground Clearance: 375mm / 14.8 in
Seat Height: 960 mm / 37.8 in
Tank Capacity, Approx: 7.2L / 1.9 ga
Weight (without fuel), Approx: 89.2 kg / 196.7 lbs
36 Responses to “2016 KTM 125 & 150SX First Test Riding Impression”
Jimmy Lewis
Questions about the KTM 125 or 150SX? We’ll be checking the comments for the good ones to answer.
Plies Hat
How does the new 150sx compare to the new 250sxf?
Jimmy Lewis
For most the 250 four-stroke is easier to go faster on due to the longer spread of power. The 150 feels much lighter. Those are the obvious things.
Matt Stavish
Is the motor as easy to use as the YZ125?
Jimmy Lewis
Depends upon the rider. If you like hit and snap on the bottom compared to a long and smooth top end overrev, then you will still prefer the Yamaha.
Matt Stavish
10-4 on the power delivery…
I can guess about the suspension, but how’s the handling? Is the new KTM chassis a match for the all-time handling king YZ125?
Jimmy Lewis
Same thing, it is a different flavor. The KTM is a little longer feeling than the Yamaha and I believe it is a a little more stable feeling.
Andy Lagzdins
Is there a 150XC for 2016?
Jimmy Lewis
No.
Dan Sessler
How do the power characteristics compare to the 2015 150 ?
Is there any increase in low end throttle response/roll on ?
Jimmy Lewis
The character is the same. Our impression is that there is a slight bit more power everywhere in the spread. The roll-on feels pretty much the same and if anything just comes on a little earlier. But you can also alter this ever so slightly with the new externally adjustable powervalve. It seemed to give the bike a feeling of having more compression when we had it at it’s most aggressive setting. That said, like the 250/300 each bike is a little different and the stock setting was the most rideable.
C0EX1ST
I ride at 5,000-9,000′ and currently have a ’13 250 XCW 2-stroke with a Rekluse, SX head, & CDI; and i plan to keep it. Yes you can override the auto-clutch but its not the same as being able to feather, dump and/or abuse a clutch to increase the fun factor when traction is available. I was ready to buy ’15 200 (love small bores) as a play/race bike when conditions are tight and there’s good traction but have since noticed the ’16 150. My question is, does the 150 have enough torque to ride single track at elevation; to climb tight single track with loose, softball size rock at altitude which we ride a lot in Utah? The idea of shaving nearly 25lbs off my 250 sounds amazing but if there isn’t enough torque to grunt up a hill, than the 200 might still be a better choice. Also, do you think anyone will make a larger tank for the 150, aka same size as a current 150 XC?
Jimmy Lewis
It really depends on your weight but the 150 will never be like the 200, or even close to it on the bottom and in the torque where you are describing. If you weigh 120 pounds, maybe. I would expect a XC version with electric start (and maybe an even larger displacement on the same chassis/bottom end platform) in 2017.
C0EX1ST
I’m 160 #s, probably 170 with full riding gear. If there will be 200 this light in ’17, that would be great news! I grew up racing a YZ 125 in GNCCs and miss the fun factor of a small bore but worried about altitude and the climbs out West. I rode a 200 a couple of months ago and fell in love with it but this new 150 has me second guessing the 200.
Sean66
I was planning on getting a 125 in the near future but have had a hard time deciding wich 125 is better the ktm or yz?
Jimmy Lewis
Or the Husky? We have not ridden them all back-to-back but they are different and knowing what you want and looking closely at the tests should answer the questions.
Jimmy Lewis
From what I have been told each different motor is set at the factory on a dyno to get the best peak horsepower and the range is usually between a 1/2-turn on all the motors. The effective range of the tuning from when I tested it on the KTM 125 and 150 is about two turns to either side of the stock setting. Then it is all about rider feel. Test by changing it a full turn in one direction and see what the difference is. Then to the other direction. For me it changed how aggressively and at what RPM the engine really came on the pipe at. Also on the 125 it really changed how the engine responded when landing off jumps onto a full load.
disqus_TNW1hizarC
Thank you Jimmy one more thing on the 125 did you get it to improve in that situation by tightening or loosening the adjustment I’m trying to narrow down exactly what characteristics are available going each way. I realize what u gain sometimes u loose something else
John
Jimmy Lewis
It is a feel thing. One of the bikes I rode felt a little lacking on pick-up so we tightened the adjuster (which puts more spring preload on the opening spring and actually makes it open up sooner) and this helped. Best is to just have the rider test different settings to see what they like. Going one direction on the adjuster can have opposite effects based on the throttle position of the rider. Trust me this is a “tuning” thing and not a faster or more power thing.
Jimmy Lewis
I played with it to find the right feel. I do not recall exactly which direction I settled on in the end compared to stock. I just felt it was better where I left it.
Kyle Nettleton
I just like to free ride and hit some motocross tracks for fun on my 450. I’m not looking to complete on a 150. I know I’m too heavy to hop on a 125. So at 5’11 and 185 would I be able to get on a 150 and flick it around still enjoying that two stroke fun?
Jimmy Lewis
I’m a very similar size (used to be heavier, not as tall by an inch) and I have no issues with the 125/150 for power on a motocross track. But I’m not so interested in freeriding on one. The power difference isn’t so great between 125 and 150 to make that much of a jump between bikes, especially coming off a 450. They are just really fun, mostly. Even our resident 220 lb. tester rode my 125 last week and was saying how fun it was and had him motivated to lose 20 pounds and then get a 125…
Jimmy Lewis
There is a slight power difference, more torque everywhere in the power for the 150. At your weight you are not killing a 125 like I am at 185 pounds so it is really up to you. There is nothing wrong with more power but then you can start looking at bigger bikes too. In the past the 125 always ran better or at least had a longer spread pf power and the 150 seemed a little more peaked. Those times seem gone as both bikes run with a full power spread from bottom to top now.
Chris
Do you know what jetting was in the 150 you tested? A buddy of mine just bought one and it has a terrible bog/burbble just before it gets on the pipe. We have tried several needles and dropped the pilot size and nothing seems to help it.
Jimmy Lewis
I do not know as it was just a quick ride on prepped bikes. Usually it is stock but I can’t confirm this. We were running pump gas, this I know. Our bikes (there were a few of them) all ran excellent.
AJ Maggi
what settings did you end up with on the 125 suspension?
Jimmy Lewis
We have not done a full test on the bike so we do not have any settings for these bikes just yet.
Jimmy Lewis
I have not had the KTM to put on our scale so I can’t confirm this. Yet KTM’s published weights have been very accurate, less fuel.
K.d. Minka
Can you comment on the suspension and how it compares specifically to the YZ125? Also, in terms of power delivery the YZ125 still has more off the bottom — even compared to the 150SX? Wondering which has a more friendly (easy-to-use) power-band for the beginner/novice/vet rider.
Jimmy Lewis
Can’t compare until we ride the KTM on tracks we are more familiar with and where we have ridden the Yamaha. As for the power, the Yamaha does have more of a hit or snap when it comes on the power and the emphasis of power on the YZ is a little lower strung in the spread. But the KTM is smoother and revs or works longer on top without such a significant sign off. So Our opinion is that it is about equal for ease of use, just different.
Jimmy Lewis
Yes. The motor is a jump forward but it is not as much as one might expect considering there is nothing similar with the old KTM 125/150 motor. The character is very similar. Yet the handling is on a whole another plane.
sharkbait
How big is your smile when you are riding the 150 compared to say a 250F or 350F? If you are hitting the gears right and hold the right hand turned all the way don’t you feel like superman and isn’t it more fun to ride? I’m an old dude and more interested in fun and kinda fast than being lazy and riding around in the same gear all day.
Bryce Oxley
Hey jimmy Lewis!!! This is Bryce Oxley.
I just bought a 2016 Ktm 150 sx.
Do you have any jetting specs you can help me out with for so. Cal?
I live in Montana now so high altitude specs would be amazing also! Thanks
Jimmy Lewis
We have not had a test bike so I have not played with it. Just rode the bike at an introduction where I was told the jetting was stock and I did not have any issues with it. Start by lowering the needle and tune from there.
Bryce Oxley
The Needle is in Position #1 Stock… It recommends to put the clip in Position #3, which would raise the needle …
Jimmy Lewis
We tested the bike at Crawsfordsville, ID. Where they have the Ironman national and GNCC. It is 700ft. in elevation.