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I agree -- the bike had lackluster torque on the stock ECU, but switching to the Vortex + the exhaust flange helped a ton. Now jumping out of a corner feels comfortable.
Were you rocking with the stock ECU?
Yeah stock. Had exhaust, screenless filter cage, tried different gearing etc. Vortex would've been my next move. I'm sure it would've helped.
I'll add that I think most people who say the 350 lacks off the bottom are probably referring to a 22 and earlier model. My 23 and 25 350sxf have more snap and faster throttle response than either my 24 kx450 or my 25 TF450 did off the bottom. Granted the 450's have what I call more midrange balls or torque, but snap at the crack of the throttle the newer 350's have plenty. And im not a lightweight at almost 100kg.
The 23+ 350 has way more bottom end than previous gen. Add Vortex and XPR exhaust flange to make it even better!
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If I end up with a 23 gasgas 350 is there a similar exhaust flange?
I don’t believe so.
Quick turn throttle cam, 52T sprocket help a ton, add a reflashed ecu or vortex with good fuel and that will help even more
Yes, you just get the flange for a 2022 KTM 350SX-F, but it's not necessary.
Ideally, you'd have one with the brembo stuff...
Here's my recipe for a sleeper 2023 MC350F that looks stock but runs very strong.
My MC350F is a holeshot machine, even though I am slowing down at age 45.
This year I grabbed both holeshots at Washougal's amateur national race in the 40+A category on this bike.
That 40+ class is like a nuclear arms race of vet class 450Fs and a couple of those guys are a lot faster than I am.
Modifications:
-Map switch (get the map switch, even if you run the stock ECU)
-Filter cage without the screen (I bought the two stroke part from a 2022 KTM 250SX)
-Airboot from a 2018 KTM 350SX-F. The velocity stack adds torque (this cost me $60 from KTM parts)
-2021 - 2023 MC250F muffler does not have a baffle like the 350 version (new takeoff from MXLocker $100)
-Vortex ECU mapped by XPR (I run the "best overall power" map and I have the "slick or hardpack surface" map on map 2)
-DialedMfg.com KYB conversion with late model YZ250F cartridges, my own valving, and 4.8N/mm springs
-REP Linkage (two piece, complete linkage system)
-WP shock revalved with a bleed shim on the HSC piston and a 45N/mm spring.
-Honda front master cylinder with the BrakeTec caliper, stock brembo pads & Galfer rotor. (I did a thread about this mod)
-Stock gearing
-Aggressive (black) throttle cam
-Hour meter
-Guts gripper seat
-Bridgestone tires
A note on the Vortex ECUs.
I believe Chad at XPR and Jamie at Twisted can remap the stock ECU.
If XPR can give you the "best overall power" map in your stock box, the only disadvantage is the lack of fuel trim screws.
I have not had to touch my trim screws with ethanol free pump fuel and she runs clean, but if you lived at elevation or ran some different fuels, you may need to make a click or two.
I've ridden my 23 MC350F back to back with my buddy's 2023 KTM 350SX-F. He has the Twisted Vortex ECU.
His bike hit 30 hours on Saturday and mine hit 27.5 hours, so they are fairly fresh.
I expected a great deal more torque from the new gen 2023 KTM and I found no real difference from idle up to mid range.
From mid range through the top end, I felt like my MC350F pulled with a little more aggression and for sure the suspension mods give the bike a ton of traction with a planted feel that allows you accelerate harder through the rough sawdust/clay loam and hardpack clay at Burnt Ridge MX here in Washington.
Currently he has revalved stock suspension, but I'll build him a KYB fork and change his shock setting after our trip to MXdN.
He just picked up the REP linkage from another forum member here as well.
It's important to keep in mind that it isn't an apples to apples comparison since the older gen MC350F needed more mods to make it equal to the 2023 350SX-F in the engine and braking department. I think I would prefer my 2024 KX450 over the MC350F if I did not do the mods. The KX has a PC pipe, air filter and the Keefer map for the 2025 model. With the mods, I am consistently a few laps faster on the GasGas than I am on the KX. In a long moto the GasGas could benefit from rubber mounted bar clamps, I did a 30+2 on Saturday and came away thinking about that when I jumped back on the Kawasaki.
Dirt start from 2024. I think this was my first gate drop on the 350F.
https://www.instagram.com/p/C7KANPahinR/
^^Nice build!
What can you tell me about Bridgestones? Either very soft track or mid to hard. Noticeable difference from MX34 or Pirelli MX32 Mid soft? I am trying different tires to find out what I really prefer.
Have to agree that the 350 doesn’t seem to be a limitation on starts.
That bike looks gooood
I haven't been running many Dunlop tires since they came out with the MX51 back in 2008 or 2009.
That MX51 was terrible, then all subsequent Dunlop tires chunk knobs quickly on the tracks I ride.
I need my tires to last more than one race.
My KX450 has the Dunlop MX34 on the rear and AT82 front.
The GasGas has my last set of Bridgestone X30 tires on it.
I think the X30 feels superior on the hard/dry clay for sure, but the suspension on the KX is also holding the tires back a bit.
I really haven't done a fair comparison on the same bike.
I'm running the current Bridgestone X31 on my YZ125 and it might be the best tire I've tested.
Heck of an improvement over the X30 in straight line grip due to the more aggressive spacing of the center lugs.
Leaned over, I think it's just a bit better as well.
Most of that comparison is on mid/hard terrain like Washougal and Burnt Ridge MX.
A side note, I actually thought the stock Maxxis tires were OK.
The rear started shedding side knobs at some point (I have the exact hours in my notebook), but the front held out for a lot longer on the same mid/hard tracks.
Man. Other than tires, maybe a gearing change and some clickers i just ride whatever bike I got. I cant out ride any of them. If your a gear head i get it but lord you guys must haul the mail.
Respectfully disagree, building and modding a bike is almost as much fun as riding one for a lot of us. To each their own though. To the original question, I’m a 350 guy and currently on a 25 FC350 heritage I made into my own factory edition. I have MX-tech ravens in it and am very happy with the results. My son has a MC 250f with the XPR dual injector and vortex. Even with the mods back to back the 350 bottom and torque is drastically different. Go 350
Bought a 2025 SX-F 350 about 6 weeks ago. The only mods that have been made are an Akrapovic slip-on, 2-stroke filter cage, stiffer stock suspension.
It's the best bike i have ever ridden.
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I agree, I've basically done exactly the same as you. Although I just put in some dal soggio inserts and first ride I'm not overly impressed. The stock air forks now are very very good.
Yeah it's incredible how far they have made it with the air forks. The last air fork bike i had before this one was a 2021 KTM and they have improved a ton from that (back then i bought the KYB inserts for the bike).
And my riding buddy has the same bike with WP Pro components suspension i actually prefer the air fork over his XACT PRO spring fork.
Yeah I had kyb's on my 23 and never really tried the stock forks. Did 10hrs on the stock forks on my 25 and was really liking them but I can't help myself and had to try the dal soggio's. Only had one ride on them so far but definitely not blown away. If anyone says they won't buy a ktm cos the air forks are crap they are terribly wrong.
I fought going to a 350 for a decade. I've owned 450's and invested lots of time and money to making it more manageable, easier to ride, more comfortable, and tamed the engine...only to be just as fast on a stock 250. I rode 250's for years and they're a lot of fun. I can get the most out of me as a rider with the small bore bike but I'm working for that speed. Downshifting 2 times going into corners, scrubbing, slipping the clutch, keeping momentum in the corners, and getting killed on the starts in the vet class. I went to the church of 350 and all is good. It doesn't have the heavy feel and arm jerking torque of the 450. It revs as far as a 250 and it carries each gear further so you're not constantly banging the gearshift. The 350 is manageable, easy to ride, and fun. Take a sip of the 350 coolaid and you won't regret it.
Man we have almost identical bikes 🤣
I'm on a 22' with brembo stuff. Haven't done the air boot yet though.
My only other cheap / worthwhile tip is to keep the rear wheel back as far as you can. We ride deeper / faster tracks - this helps stability a lot, and the rear end definitely tracks better in ruts w/ acceleration chop. Works really well in conjunction with the REP knuckle.
We'll be at MXoN as well!
Pit Row
Any reason you went Raven over Blackjack?
None other than Corey at protune recommended them when I told him what I was looking for and I trusted his judgment
Get a 250 and when you feel it’s time to step up to the 450 get a 350 instead.. for almost everyone the 350 has all the power you’ll need and be much more rideable and fun.
Yes. I got a 350 and was totally petrified it wouldn’t have enough power as I’ve always had big powerful bikes 1250cc Ducati 1000gsk etc and 800cc and 500cc off-road bikes quads etc..
I rode the 350 and was immediately like “oh shit I made a mistake” then after riding it a little longer I started falling in love. I found I could hang it wide open and ride IT not the other way around. It’s just a beautiful amount of power and feels light still. It made me feel fast instead of guarded. I could attack hard and thrash it without it tiring me out like the 2 strokes would. The reason why I ride is for fun, so that’s why it’s the bike I always end up on…
Now I just need to go buy one again!
Now why did I suggest the 250 after talking up the 350?
Well I’m thinking if your just starting out the 250 would still be best for a little while. The 350 is still a lot of bike!
I've been in my 2010 Honda 250 for awhile. Love the bike. I feel like I'm ready for a 350 though.
My 2020 KTM 350 SX-F ran a high compression piston, a FMF 4.1 pipe, K tech inserts and air bladder converstion. Even running an MX14 I still had issues with it pulling well enough at times. Though I live at altitude and Im around 240 pounds so that probably made the most difference. Fun bike regardless good to hear that the newer ones have some more bottom to them.
Only reason I’d ride a 250 over a 350 would be because I was very young and light, as a first big bike. Or because the 250 class is what I wanted to race.
350 all day long unless that. Or if you are really big and lazy or actively racing fast pro, then just go 450.
I noticed this exact thing yesterday. It's my first season on the 350 so obviously trying to figure it out. But I got that exact second-third feeling you'd described.
I think this is why I love 350's so much more than 450's. Most tracks I ride are on the faster side and the 350 wide open in 3rd and 4th just feels so much safer and easier than a 450.
YZ250, to a SXF450, now on a 2024 FC350, so much easier to ride, felt at home immediatly.
62Yrs, lifetime slowguy
Alright, so my top 3 choices are a 2023 gasgas 350, a 2022 mc350f and a 24 KTM 350 sxf. I don't think either one is going to be a bad choice. But can anyone give me the differences between the two?
Having owned the old generation 21 and 22 FC350, and 23 MC350 and now the new generation 25 FC350 the new gen bike in my opinion is much better. Feels lighter on the track although the scale says otherwise. Better power delivery. Providing condition, maintenance records, hours, cost are all similar go 24 ktm. The MC 350 is a great bike but the ktm will have Brembo, map switch, etc. the gg doesn’t (unless its been modded)
To add to this, my 23 MC wasn’t stock, I had a vortex ecu, map switch, Akropovic full exhaust, etc and my 25 was better of the showroom floor.
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