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Written/Tested By: Gardner Tarlow
Wow, what a blast it is to help Kris test ride new bikes. Be it a two stroke or four stroke in today’s day and age, every bike I’ve tested continues to impress me with the advancement of bike technology. For many of us, our first full sized bikes started with the two stroke 125. Back in the day it seemed like huge improvements in technology occurred every few years. The 2025 KTM 125s continue to push the limits in technology and the 2025 KTM 125 XC does not disappoint. This bike isn’t just a 125 SX with an 18” wheel and softer off-road suspension, but rather a purpose-built, off-road race bike designed for off road juniors coming up through the ranks and pushing the limits the same way the SX is built specifically for motocross. The reality is, if you’re an off-road rider and enjoy small bore bikes, this bike provides so much more, for so many riders.
The 2025 KTM 125 XC has undergone two intensive years of research and development that has resulted in a reworked and lighter frame, updated engine mounts and a new, more durable chain glide. The airbox is now a one-piece construction with a redesigned air inlet sleeve and snorkel, which prevents deformation and improves airflow. The electronic fuel injection has been setting the standard in performance and no longer are there race day concerns with jetting issues. The ability to optimize power in spite of variable temperatures or altitude make race day prep less stressful. With leading edge technology, the 2025 125 XC ECU features two maps allowing the racer to switch between map 1, providing the ultimate in power on hard pack surfaces and map 2, optimizing performance in soft sandy conditions. The 2025 XC and XC-F models have all received major frame updates from Factory Racing efforts. The frame area around the rear shock mount has been updated, and streamlined. The front area of the frame has also been updated with different wall thickness compared to previous model years as well as renewed engine mounts improving flex for better cornering behavior. The WP XACT Closed Cartridge Spring forks have been reworked to optimize front end feel and performance. The WP XACT rear shock has also been reworked and updated to perform optimally with the updated frame and rear linkage.
I’ve been fortunate to ride many of the available small bore 125s and 150s over the last 4 years but for one reason or another I haven’t been able to get my hands on the 125 XC. I was stoked when Kris asked me to ride the 2025 125 XC. As much as I wanted to test this bike in tight difficult single track, I ended up setting it up at Glen Helen and Cahuilla with the aid of my friend JP, who happened to also have a well running carbureted Husqvarna TC 125.
The 2025 KTM 125 XC is a blast to ride at the track as it should be; this frame is basically the same set up as the KTM 125 SX frame. Yes, the fork is a closed cartridge spring fork and set up for off road as well as the shock is set up slightly softer than the SX set up but both the fork and shock work very well and can handle just about everything but the very biggest hits at the track. I generally ride the first four hours of most track days and there are still plenty of braking bumps and acceleration chop to uncover poor suspension performance but I’m also not the guy riding a track that has been beaten in and waiting to send me over the bars, two hours before closing.
The WP XACT closed cartridge spring fork is set up for riders in the 165-187lb range. At 185lb I’m at the limit for the stock ideal weight. The recommended most aggressive fork setting calls for 7 out on compression and 13 out on rebound, however my final setting was 5 out on compression, 11 out on rebound and forks set at second line. In general, the fork feels very plush in its initial stroke, soaking up small chatter and moderate braking bumps very well. The fork and front end of this bike feels connected to the ground, performing well on initial lean angle of corners. This same connected sensation gives the bike confidence in both flat and off camber turns. Note, the stock tire is a MX33. The fork feels like it has good hold up in general and resists bottoming off of moderate size hits. Larger hits from overjumping did result in a few hard hits, which are the result of rider size, spring rate and valving for offroad. For off-road and single-track purposes, I softened up the fork and rebound to the recommended stock aggressive settings and the bike performed very well. The forks’ ability to feel plush for off road and still handle bigger hits and G outs found on the trail was impressive. Overall, I really liked the closed cartridge spring fork on this bike versus the air forks. With a stiffer spring and motocross valving, this fork could be the optimal KTM set up for moto (if you’re a mellow B rider) and absolutely performs well for off road.
The WP XACT rear shock is similar to the SX rear shock but with softer settings for off-road purposes. Again, I’m on the border of the stock spring rate but this really didn’t produce an issue for either motocross, off-road or single-track purposes. The recommended aggressive setting was LS compression 13 out, HS compression 1 out, rebound 13 out and sag at 105mm. My final setting remained at 13 out, 1 out, 13 out. The rear end of this bike was well mannered and performed well in both braking and acceleration bumps. Having an 18” rear tire and more tire sidewall more than likely helped with the acceleration bump performance. The rear end overall tracked well and felt good on both moderate and big hits at the track and off-road.
The chassis on the 125 XC is the same as the 125 SX and the handling of the 125 XC for that reason is very good. Like all the Austrian 125s this bike is an absolute blast to ride on tracks or trails, corner to corner it’s fun feeling for me. This bike feels planted and connected to the ground as you initiate lean angle entering into area 1 of corners. As the bike continues into area 2 of the corner it feels very neutral almost just wanting to lean over automatically and then just rails through area 3 of the corner like you’re on a slot car track. I believe the anti-squat rear shock design does a nice job keeping weight on the front wheel mid corner as you accelerate assisting with consistent cornering performance. This KTM 125 XC has given me more confidence in my riding the past couple months that I normally DO NOT HAVE!
The motor on the 125 XC is a very capable motor for all off-road applications. The motor, inner transmission gear ratios and ECU mapping on the 125 XC are the same as the 125 SX with the exception that the XC has a sixth gear. KTM pulled a page out of Jody Weisel’s tool box and simply added a tooth to the rear sprocket, which allows the XC to perform really well in off-road and tight single-track trails. The SX final gearing is a 13/50 and the XC is a 13/51 final gearing. The motor provides the same ECU mapping as the SX with two maps. Map 1, is for hard pack surfaces and map 2, is for soft sandy conditions. Map 2, I believe is simply a richer map and although I tried this map 2, I didn’t notice a significant benefit or difference at the track or on the trails that I tested on. With an extra tooth on the rear sprocket of basically a 125 SX you don’t need me to tell you the motor feels really good. The motor has a good bottom end with a strong linear pull from mid to top end and good over-rev. Being that I am in in the 180s for weight, the KTM still can pull me around with enough excitement that I am not bored or mad that I have to dog paddle my way around corners. This little engine can withstand the rigors of an old vet rider. With the 51-tooth rear sprocket the motor is impressive with its ability to essentially idle and crawl around in first gear with pretty impressive throttle response. Second gear also provided the ability to move through tight, technical single-track sections without a lot of clutch abuse one might normally feel with the stock 13/50 gearing found on the SX model. To be honest, as well as the XC works on the trail, I was certain there must have been lower internal gearing and ECU mapping for the bike to perform as well as it did. Regardless, the KTM 125 XC ability to run at very low RPM and respond without a lot of clutch abuse is impressive. With multiple alternating riders there was nowhere on the track the carbureted Husqvarna TC 125 could subjectively pull away from the KTM 125 XC.
As much fun as I was having at the track, I was able to spend a few days in the hills of the high desert as well as some tight, fast single-track in San Diego County. This is where the 125 really performs well. Dicing in and out of corners, ducking trees and bushes, the 125 really performs well in the tight terrain and doesn’t fatigue me as much as larger bore bikes typically do. Yes, the bike is at a disadvantage when the trail heads up hill, and yes, you do wonder if you’re going to blow it up, but this motor just keeps on screaming. This bike weighs 208 lbs. and when you find yourself either in a rock garden or having to manhandle the bike, 208 lbs. seems really light on the trail. In the wider open areas, it can certainly be annoying chasing your buddies on big bore four strokes but the technical skills practiced and learned on a 125 can make you a better overall rider that undoubtedly will transition to other bikes.
If you’re a small-bore motocross or off-road racer, KTM SX and XC are purpose-built bikes designed for your task at hand. If, however, you’re a vet or weekend rider, enjoy both moto days, off-road and single track like me, this XC bike performs well in all of these arenas.
The 125 XC lists for $300 more than the 125 SX. What do you get for this $300? Basically an SX with hand guards, skid plate, kick stand, 0.4-gallon larger gas tank, an extra 6th gear with an 18” rear wheel with a 51-tooth rear sprocket and the candle on the cake is the WP XACT Closed Cartridge Spring forks (the forks are worth the 300 dollar upgrade alone in my opinion).
If you like to think outside the box, here is a thought – buy the 2025 KTM 125 XC, have the better fork and buy a 19” rear wheel with a 50-tooth rear sprocket and you have a bike that can convert from moto to off-road and single track with the change of a wheel. Oh, and give away that air fork pump.
