I ride a 350. 6'2 and 215lbs. Looking to add a small bore, either a 125 or 150. The expectation is that this bike would also be available for my 13 year old son who is 5'10 and 175lbs who currently rides a '21 KX 250.
Is the 150 a better option for bigger guys or is the 125 as good a choice? I hear conflicting information. Some say the 150 powerband is too narrow and signs off too quick, making the 125 for fun requiring less precision and effort in shifting. While some say the 150 has more excitement and is easier to ride with increased bottom-end. The choice would be a KTM or Husqvarna, 2016-2018 range. Not looking to spend a ton, just want something to add variety, budget is where it is based on the expectation I will need to spend on forks and this will not be a primary bike.
Looking forward to some opinions.
Maybe not much of a help for you, but the new 150 XC-W has caught my eye recently. Considering that over the 300.
The Austrian 125s I’ve ridden were good, but pipey compared to the YZ’s. I’d say snag a 2-3 year old used YZ125. I don’t think that motor can be beat for ridability and ease of use.
I can't help much either but I always preferred a well-tuned 250 over any of the 300s I've ridden for the exact reason you mention about the 125/150. (edit: I was meaning they have lots of torque but don't rev well at all)
I’d let condition, hours and extras sway me before the displacement.
Many like the 125 over the 150.
Pick one and run with it. I am 6’ 200# an had an absolute blast on a 2000 CR125. (Avatar pic). My friend has a KTM 150 but often says he prefers his YZ 125. As we speak I am trying to sell or trade a 2020 Kawi 250 for a current YZ 125
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I'm one of them.
I rode both and ended up with the 125sx. Was more fun for me. 150 required more shifts per lap with a narrow powerband.
The 150 needs to have the gearing changed otherwise it rides like what you experienced. Having to shift to fast through the lower gears. It has the power to pull taller gearing 14t front helps or drop another tooth off the rear.
I own both 125 and 150 2018s
The 150 rips for sure, I think people say it's narrow because it's got more torque and gets it's business done. The whole 150s don't rev is an old wives tail imo.
The poster above said it best, just pick the one you find in best condition and value
I haven't ridden an austrian 125 but i prefer the yz125 over the ktm 150. To me the 150 just hits hard in the middle and signs off, the yz on the other hand loses a bit through the middle but continues to pull up top.
When my mate bought a 150 I was excited to try it because of all the rave reviews I'd read about it. After 4 laps I got off it and went back to the yz
I own a 125sx and 150sx .. as others have said, buy based on condition of bike and price, Both bikes are similar. I would say for deep sand whoops out of the corner that my 150 will just have enough to make the difference of staying on top of the whoops. I weigh 190lbs
I think a lot of people parrot what they read in MXA. So little difference, but the 150 does get down the road quicker.
100%, real world for an average dude you'll have a blast on either.
Ridden both recently, while on the hunt for my own, I'm a big dude and I'd happily have either, or a YZ, shit I may even grab an old Super/Ultra Evo bike as I'm keeping my old KTM 350 now.
I have 2013 150SX with ported cylinder, HGS pipe, BUD racing cylinder and the bike absolutely screams. The myth about not getting 150 rev like 125 is absolutely not true. There is more power than 125 trough the whole power curve and I have added heavier flywheel to get into ground more efficiently. I have to admit that I'm actually faster aboard my 150 than I'am with my 2016 250SX as long as the track is not too soft and I really enjoy riding the 150 as a over 40 years old vet rider
As a 21 150sx owner I can say my bike flattens out quite abruptly. I shift a lot.
I have had both and weigh 185 lbs. The 150 lets you ride 3rd more and is much better off-road because you can lug more. I felt like I had to shift the 125 more than the 150. The 150 has a 48t rear sprocket and the 125 has a 51 so they should be geared differently. A 51t on the 150 is probably going to be too much. You might be able to gear the 150 up more than stock. I know that stock in 3rd gear when it gets on the pipe it pulls pretty hard compared to the 125.
The TPI 150 xc-w is not the same and does not rev out nearly as strong as the SX/XC versions. From the review I just read the 150 TBI bike is a little stronger than the TPI but still not as fast as the SX/XC bikes.
My exact experience on my 2017 ktm150sx. Most fun bike to ride I have ever had! I’m 66 years old and 175 lbs.
The 150 will get the job done but the 125 is more fun. I assume that is the reason for buying a small bore.
A few weeks back there was a guy @ the track with a couple TM's, 250 and 144. He said his buddy has the 125 and he should have gone that route. He was an older, slower vet but not that old. YMMV!
You'll prefer the 150, your son will prefer the 125.
I'm in my 40s but short and light. I always thought 'funnest bike I ever rode' was just echo chamber bs that people spouted out until I rode the 150 and realized it's true. I still think about that day riding it.
Pit Row
I've got a 22 150 the bike stock with stock jetting was absolutely dangerous not fun at all total flat spot on the bottom did sign off really early I'm a slow guy I hated it my son's fast he wouldn't even ride it! I got the jetting better but not perfect through the jetting thread in the tech section made it at least rideable my son loved it at that point lol only wrote it for about 4 hours to try to figure out what I wanted to do with the suspension then took it to Twisted had a complete motor done same package they did for emig and brown when they were on 150s I also replaced the crank due to all the failures and they put a vhm head on it with their spec and then dynoed and jetted it for U4.4 the bike is absolutely magical will lug from complete bottom and Rev to the Moon super crisp no flat spots anywhere was able to drop down to a 47 rear sprocket like I said I'm old and slow and it made it easier to ride my son loves it more than he's 250sx LOL it's a complete rideable rocket ship!
This has been my experience with carbureted two stroke KTMs I've ridden in the past five to ten years. Terrible jetting and suspension settings from the factory, but lots of potential.
A buddy is on his second 2022 KTM 150SX and it's excellent. His first one (same year) had different mods and it kinda sucked.
His first bike had PC exhaust, Rad Valve, minor jetting changes. It had a super narrow power curve focused at a very high rpm range.
His second bike has the FMF pipe, V-Force, a different head and a Keihin carburetor. The bike pulls through the mid-range like my modified YZ125 and revs out farther too. It probably has a solid two to three horsepower more through the curve, then keeps pulling another 1000rpm after my little Yamaha signs off.
Unfortunately he's low-effort for testing individual parts and jetting, so I can't really say which parts between the two bikes make the most difference, but that second combo is a real winner. He runs a 50/50 mix of leaded race gas and ethanol-free pump premium like most of us around here. He's also getting pretty decent starts in the 30+ class.
I also have the FMF Factory fatty and the v-force4 reeds. Mine was built as a package so I don't have any individual test results either but I'm pretty convinced that the crank was part of the issue for the flat spot on the bottom no matter what I did with the jetting I couldn't get rid of it and a lot of guys on the jetting thread we're saying the same thing even swapping over to keihn carburetors they could not get rid of the flat spot! And yes I agree don't even want to talk about how bad the suspension was stock as much as these bikes cost they should come better set up!lol
When you said crank, did you mean carburetor? My buddy's bike has the original OEM crank and it rips.
I think the Keihin carb is likely the big winner. Another buddy also did the Keihin swap and he said that was the best mod, but I haven't ridden his bike.
No I meant crank I think they're pressed too tight which was causing the failures and maybe a little bind off the bottom and I'm still running the stock Mikuni carburetor Twisted said it got the most horsepower! The bikes only ridden on the track I've heard the keihn is awesome for trails and really makes the power Broad! I don't believe all the cranks were defective hopefully he got a good one👍
I guess if the crank is bound up, you'd feel it.
The crank doesn't not have to feel bound up to bind up. When the thing gets hot @ 10K is when it will show up if the big end bearing is pressed too tight. Lack of thermal clearance.
No shit?
Same - 67, 6'3", 179lbs, 2013 150SX since new. Best MX bike I have ever had (since 1972).
I just rode a 19 150 back to back with my 19 YZ125, this weekend. I honestly thought the 150 had a lot of power, but the placement just wasn't for me. I also, prefer the YZ chassis and suspension. I'm not saying the YZ is everyone's best choice, but just for me. But in general, knowing the ktm 125 already has a power advantage on the Yam, I expected to like the 150 more, but I just didn't. It has a pipe and RK head too. I've ridden that bike a couple times now, but I've had my 250F with me on those other days. Maybe on the right tracks, I think the 150 could be a monster though.
Yes, the short power with no over-rev that everyone complains about on the 150 is mostly due to the horrible stock jetting. Same for the 250SX. It falls off super early with stock jetting. With the jetting from the thread in tech it's a totally different animal, much broader power with lots of overrev.
On the 2022 flat spot issue on the 125/150, not sure if you looked at the thread recently but I think I solved that. I did extensive testing with a 2023 GG-125 and, long story short, the bike needed a leaner needle than what the thread indicates for the 2017-2021 bikes. I found this to be true on both Keihin and Mikuni carbs. One hypothesis is that this is due to less advance on the ignition in the newer ECU they started using to address the crank problem.
This was my opinion too, I preferred the broad power of the YZ125 over the KTM 125 and 150 on most tracks until I rode a good 150SX. The one my friend is racing has changed my mind. It pulls a tad harder in the mid range than my YZ125 and runs way higher into the rpm range with far more power up top. The chassis on the KTM feels longer/bigger than the compact YZ, but I adjust to that in a lap or two. With a KYB spring conversion in the forks, the KTM becomes a superior bike.
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