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VHM racing just did a dyno test of a brand new Yamaha YZ250, so now we can do a near head-to-head recent comparison of the 2026 Beta 250 RX and 2026 YZ250 carb'd engines. Same dyno, same dyno operator, but different day/ weather;
Stock engines---
YZ 250: 43.7 hp and 31.3 ft lbs of torque
250 RX: 46.2 hp and 32.3 ft lbs of torque
Modded engines w/ higher compression cylinder head and CDI change (note: YZ test also had the addition of an HGS exhaust, the RX used stock exhaust)----
YZ 250: 47.5 hp and 34.4 ft lbs of torque
250 RX: 48.3 hp and 34.1 ft lbs of torque
FWIW https://motocrossactionmag.com/mxa-race-test-2026-beta-25orx-350rx-two-…
No direct comparison.. we dont even know if was the same dyno, and only a recollection rather than showing the original dyno results for direct comparison..
MXA quote; "They guessed the 250RX would be about 2 to 3 horsepower slower than the Yamaha YZ250, which peaked at 46 horsepower last time we checked it on the dyno".. so less reliable source for a direct comparison.
VHM has no loyalty to any manufacturer whereas MXA has made their test videos into market advertisements of various products. I have noticed that they do coddle the balls of the companies that butter their bread.
I assume the KTM blows them both away - peak power wise?
Based on VHMs dyno tests, yes on hp, but less so on torque. Their latest test was on a 2023 KTM250SX with fuel injection. It dyno'd stock at 54 hp and 34.4 ft lbs of torque. With a 12 degree high compression piston and HGS silencer it dyno'd at 55.9 hp and 35.3 ft lbs of torque.
However, big caveat that people often do not understand. An average dyno is intended to measure relative power to compare the impact of modifications/ tuning on power, and less useful to measure absolute power since it is so sensitive to calibration. You have conservative dynos and "happy dynos" because of this. VHM may have had their dyno recalibrated between 2023 and 2026. Those horsepower numbers seem a bit too optimistic. Their test of a carb'd 2019 KTM 250SX has even better numbers.
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The carbed 250SXs were beasts. 125s too.
Yep, what this calls for is a proper shootout. Preferably with 250's of all religions across the board.
Kudos for merging coddling balls and buttering bread in same sentence 😆
Just say the tbi bikes make more power.
Stock exhaust on the Beta is Arrow. No slouch.
Yes, a full on MX 250 2T shootout is required. Yamaha - KTM - Husky - Beta for sure…. Would be cool if Fantic was allowed to play too.
Be aware, back in the day when all the Japanese manufactures made a 250 2T the YZ was the weakest on the dyno, but was the most beloved engine. The CR250 was the strongest on the dyno, but the most hated engine.
The YZ is still very competitive for a 2001 engine…
Here are some comments on the 2007 250 two-stroke shootout:
Rank
VHM dyno confirmed that a carb'd 2019 KTM 250 SX made more horsepower and torque than a 2023 TBI KTM 250 SX, as I was saying.
In addition to a 250 2T shootout, I am looking forward to a shootout of 300+cc 2 strokes, including the Kawasaki KX 327 vs. Beta 350 RX vs KTM 300 SX vs. Yamaha YZ with a 325cc big bore kit.
The bigger ones I'd like to see compared with the 350 four strokes as well, believe it or not. Much like the 250's, in many amateur and vet classes plus just bikes for practice and play, they're being cross-shopped by the same riders.
So you’re telling me that 25 years of development is worth about 2.5hp? Even less when modded 😂
Early 2000s KTM 250s regularly punched out 50+hp on various dynos, but they were a handful to ride. I expect the curve on the Beta is more linear?
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Pit Row
VHM dyno tests;
2019 KTM 250 SX with carb;
Stock: 59.5 hp and 38.35 ft lbs of torque
Modded: 60.7 hp and 39.1 ft lbs of torque (with a 12 degree piston and HGS silencer)
2023 KTM250SX with fuel injection;
Stock: 54 hp and 34.4 ft lbs of torque
Modded: 55.9 hp and 35.3 ft lbs of torque (with a 12 degree piston and HGS silencer)
Not sure if this is apples to apples enough because there are 4 years separating the dyno runs, and I mentioned that dynos are impacted by calibration and need to be recalibrated from time to time, so we can't expect the dyno to be calibrated exactly the same over long periods of time. I would expect the carb to make a bit more power than the fuel injection, but not a massive difference. A carb is a simple but efficient device that is excellent at atomization of the fuel, and engine builders for cars know this well. However, there are things the EFI can do that the carb can't. EFI cars usually start easier, can adjust for altitude and weather, etc.
No way my 2021 250sx is making 59hp more like 49 at best.
It can be a waste of time trying to compare absolute power levels with the average shop dyno and then trying to compare against different shops. That is not what these dynos were intended for. That is why the initial VHM dyno comparison of the 2026 Beta 250 RX vs the 2026 Yamaha YZ250 is more meaningful. People are getting hung up on the actual number instead of the relative difference measured on same dyno back to back. Nevertheless;
Pro Circuit dyno of 2019 KTM 250 SX.
Stock:49.37 hp
After tweaking power valve: 51 hp
2019 2020 KTM250SX on Dyno - Pro Circuit Pipe and power valve adjustments = POWER !!
Put the 2 strokes in the shootouts! Make shootouts fun again
I've read that if you go all out on a yz250 you can get 8hp over stock. I think that's probably about all you'll get out of it without a fairly major redesign.
On pulpmx, Steve has said several times that ktm had them tear down magazine bikes, port them, and basically make them into the best version of that engine they could. Would have been better if they'd re-valved the suspension and left the engine stock 😂...
I was referring to the other manufacturers.
I ride in the woods so hp isnt nearly as important to me but I cannot find any source that shows a yz or rx making more power than a 250tbi from the factory. The seat of the pants test agrees.
I have wondered myself why the 250 tbi has been out for going on 4 years and not in one shootout with other carb bikes.
Those 2006-2007 RM 250’s were my favorite bikes ever made.
You can make significantly more hp, but at the the expense of the power band's width, making it unrideable.
Peak hp is a poor metric, usable torque across a broad rpm range is a better metric.
My 2018 250sx with jetting and a PC pipe/silencer made almost 52hp on the dyno. KTM changed something in 2020 and those engines made a little more power, but I think it was only 1 or 2 more.
1999 is when the current engine mold made it's debut. Only minor changes have been made to it since then.
Exactly! Peak horsepower in not the metric to look at for a strong, easier to ride bike. You want a strong torque curve that starts early and has a nice linear curve.. one that starts high and has no bumps in the curve. This is what we feel when ride a bike and talk of "seat of the pants" feel. You feel torque not horsepower. Torque, not horsepower, provides for acceleration. Drag racers know that if they need a better ET, they need to build a motor with better torque, and if they want to improve their trap speed through the finish, they need to build a motor with better horsepower. Thats said, horsepower and torque are related. Horsepower and torque curves will always cross at 5252 rpm on the dyno. Mathematically, the relationship is HP = (Torque × RPM) ÷ 5,252.
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