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I haven't ridden a 125 in YEARS. Looking to add one to go alongside my 350.
Question - MXA always says the 150 is more difficult to ride compared to the 125, do any of you guys share that sentiment?
Also, they've claimed the YZ is a easier for a Vet guy to adapt to I guess based on the notion the power is a little easier to keep on the pipe; I rode a buddy's YZ139 last year when I had a flat. It felt pretty slow so I'm not sure I would even notice the difference anyways.
All opinions are welcome! TIA!
Question - MXA always says the 150 is more difficult to ride compared to the 125, do any of you guys share that sentiment?
Also, they've claimed the YZ is a easier for a Vet guy to adapt to I guess based on the notion the power is a little easier to keep on the pipe; I rode a buddy's YZ139 last year when I had a flat. It felt pretty slow so I'm not sure I would even notice the difference anyways.
All opinions are welcome! TIA!
Zero experience on a 150 though. Probably a blast too! See where you can get the best or closest deal; maybe that will make the decision for you...
The 125 suffers from this too. There's a great jetting thread on here if you want to fix the mikuni. Or you can do what I did a put a pwk keihin on with the jd jetting kit. I love it with the pwk now.
The second issue is the gearing. Stock it has 13 / 48 the 125 has 13 / 50. The stock gearing on the 150 isn't enough. It makes it sign off to fast up top and you end up short shifting through the lower gears too quickly. Which makes the power feel short.
To fix this issue you either go with a 14t front sprocket or take a couple more teeth off the rear. I didn't like how the 14t front fix. It was really close to the clutch cylinder. So I now run a 46t rear on it.
Ahhh soo much better now it makes the lower gears more useful. Not short shifting, the lower gears wind/rev out more. It makes it more like the 125 gear ratio wise. Really enjoying it now especially on the mx track. It has plenty of power to pull it just fine.
This is not my first 144 my 06 yz125 was a 144 for 15 years I owned it. I had to do the same thing with re gearing it ended with a 14/49 combo on it. My friends 06 cr139 also took like 3 teeth off the rear.
Most of the test reviews don't touch on this subject. They always try to gear it like a 125 for maximum acceleration and it winds/revs out too fast. Not taking advantage of the power increase properly. It's similar to like taking a yz250 and putting a 13t on it. It will be great for acceleration but wind out too fast.
Single track riders wouldn't mind but take it to a track. And that stock 14t will be back on it after a lap or two. The only minor trade off is yes you will have to use the clutch a tad bit more. Riding it more like the smaller bore it is.
But you're really not on the clutch as much as a 125 rider would be. And it has the power to pull it, so you can still be a little bit lazier with it.
I wasn't super happy with my 150sx at first but now that I've put the pwk on it. Fixed the gear ratio I love it. It rips now.
The Shop
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
Luxon 4-Post Bar Mounts
$189.95 - $239.95
It's a small-bore two-stroke... they were never designed for bottom-end power, they were made to scream. Kill a little of an already non-existent bottom end for a lot more up top.
If you are 15 and 130lbs, get the one-two-five.
If not, get the 150. It doesn't sign off early like people think, it just comes onbthe pipe with authority in the mid range snd it eclipses the top end a little.
Agree with comments on the gearing. I am thinking of going 13,50 and riding 4th and 5th a bit more.
When using rhe keihin stic setup, the bike screams and is a real handful to ride. ... so much fun.
I had the chance years ago to ride a full GYTR YZ 125 on a Demo day back to back with my 2016 150SX and the Stock 150 was more powerful.
I would choose a 150 over all 125.
Its a perfect Play and Fun bike
Hammer 663s
Hey I know this is a old thread but I recently got a 2020 ktm 150sx. Its got the mikuni and it has that signature stutter in the mid range. I will try to modify the slide to a #5 at home just so I don't break the bank besides if it doesnt work out I am looking to get a pwk. Did you get the pwk from jd jetting as the package they sell? If so does the chart include jetting for various temps as I'm in canada haha. Also how is the bike holding up, still enough power to have fun on? also how often are you rebuilding the bottom end. Thanks!
Old thread, but a good reminder that the YZ125 is the best bike of all time.
You also need the jd jetting jet block gasket for the mikuni.
Do yourself a favor and run the best PWK mod'd by STIC. It's the STIC Super X PWK 38/40mm. Only try it if you want the power to hit right off idle and pull harder than a $5k race build. Pump gas and no engine mods needed. Just a heads up. These guys had to de-tune from their sled banned carbs. Out of Wisconsin, vortex@sticfuel.us
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