Can we talk 2 strokes , carbed and EFI for a minute?

My motor guy, pretty well known in the industry, hates the EFI 125s. Too many sensors, too many issues. The 20-22s were the last great KTMs. There's quite a few young racers here in the PNW that have had all kinds of problems with the new stuff and we've seen it happen to friends at Washougal, PiR, and Albany. There are some ways to reset the PV and TPS and other subsystems but I'm not very familiar with that as our last 125 was a 22 and we've since moved on to 250s.

You will hear from some people that like them, and South Bay Moto Performance seems to have figured them out. 

I’ve got a 25 Ktm 300sx with 20ish hours on it and I love it.  No issues.  Runs amazing, power delivery is awesome and it barks.  I’ve owned lots of 2 strokes, mostly Yamahas, and my KTM is my preference by far.  

I would think the extra weight and different power output wouldn’t be much of an issue on a 300. But on a 125, it would be a big difference imo.
https://motocrossactionmag.com/2023-mxa-125-two-stroke-shootout-husqvarna-tc-gasgas-mc-yamaha-yz-ktm-sx-go-to-war/

2023s Weight:

KTM 125sx - 203.7lbs, 216 with fuel

Husqvarna TC125 - 204lbs, 214 with fuel 

GasGas MC125 - 192.9lbs, 203.9 with fuel

Yamaha YZ125 - 199lbs, 209 with fuel

Don’t get a EFI 125. 

With that being said I have 2 for sale, a mod and stock  😂

Seriously though, these bikes are complete dog shit. I’ve had 3 and our carbed 22 Gas Gas would eat them alive on performance and reliability. Also, these resale value is terrible because no body wants them. Just don’t, save the headache, I wish I would have.

My 23 Xc 300 has the best motor of any KTM I have ever had.(probably have had 10 300's) My last one was a 17 and all I can say is the TBI runs like a trials bike or a top fuel dragster. I can take it from sea level to 14K and it runs great everywhere. 

Efi two strokes are amazing, also carb two strokes are amazing! I’m on my third efi one, 23 300 sx, 24 300sx and now a 25 tc300. I definitely think they have improved from early 23. It kinda crazy because they are completely different feeling while also being not that different at all! I know that makes a ton of sense but it swear it’s true! The EFI 300 is legit the most four stroke like two stroke you could ever have, but it is also absolutely still two-stroke! To me the carb bikes are slightly more exciting when they run well, the efi bikes are much more efficient as pure race machines and they run perfect all the time everywhere. My tired end of the moto laps are much easier on the efi bike. 

Not a lot of time on the 125 but the one I rode was rad too. In fact, I have a 22 fully built TC 125 with cone valves and 3K into the motor by Jim Haeseker, it fucking rips 42 hp! I would happily trade it straight across for a new stock 25TC 150, I love the motor on it but I like the 23+ frames so much more!! so if anyone wants the “vastly superior” 2022 carb 125 hmu!!

What’s up jeff… good to see you posting again! 

Most reviews say things like: “the latest efi (especially TBI) is a significant improvement. It’s so good, it’s almost as good as a carb!”

I’m almost certain I’ll get a TM300en, with a carb. (Still available new with your choice of TBI/EFI or Carby)

The stock ECU is locked.  You can't tune it.   So if it runs crappy, like quite a few do, you are stuck like chuck.  If it throws a code you have to go back to the dealer and pay to have it reset/reflashed.   Guys get around this by dropping a few hundred to over a thousand dollars on aftermarket ECU's from GET, TSP, SBM, etc.  They have other issues with sensors and wires that can cause intermittent cutting out and failure to run.  The worst part about them is that when you get online to complain about the bike having problems, the other TBI owners will imply it must be your fault because their bike runs fine!  hahaa  Even when running perfect, they do not have the same feel as a traditional 2-stroke and just feel "slow".  They also have a rev limiter that can be annoying if you're a guy that likes to rev a 2-stroke way up top.

This was an early dyno run when the get ecu first came out on a 23 125sx. Think it was Harris perf. The crap flat line was stock. The light blue was the get. He through up the green from a 22 hayseaker for fun to compare. 

I just think that, with the 2T EFIs being, largely , KTM Group, it's down to them, and there Eff Ups and / or Achievement's.

I've largely had mates that have had No Problems with their TPI or TBI Pierer bikes, but those that do, tear their hair out.

But, that's a bit like many initial problems  / expenses associated with early EFI 4ts. 

Yes, TM have EFI available , and, indeed I read a few problems with them, at times. But, I think, TMs problems seem to be more about their Electric Powervalve  (re-setting?) , more than the EFI?

Fantic -  I've been watching Highland Cycles YouTubes, and it appears that their system is well sorted.

Yet to see Riejus EFI 2t.

Plenty of people spend a s**tload on 4t ECUs / Whatever you want to call the 'brains', by the way.

Me, I'm Not scared of EFI, but, I still ride / own a Carb'd Dinosaur, and get to ride mates various Modern, Trick 'Space Ships', at no cost or investment by me. I feel like a bit of a winner, with that!

But, for 2ts to remain available, some sort of Brain Controlled Fueling, is going to be needed. Those Bastards in charge of things, will, eventually go after ALL parts of Motorcycling.

It will be interesting to see what the much mooted Kawasaki 2T will have as a Fuel Charge Delivery System. They are a far bigger company than all the other EFI 2t mfrgs combined, and, hopefully, would have learned from what has been available, prior to their re- entry into 2Ts. One hopes, well, expects that they will have.

We had a new 23 TC 125 for about a month a few years ago. Tried everything possible to get it to run clean and finally gave up. My kid didn’t trust the bike and I didn’t trust the fact he didn’t trust it. Found a gently used 22 SX125 and lived happily ever after (or until 250f time anyway) I’m still not ok with the thought of a company releasing a bike that just wasn’t ready. They made their customers paying test riders. 

2023  300SX with 125hrs. Ran it stock for 50hrs, midrange hit like a mule, had it tuned by John Ross at Tpituning, smoothed out the big hit, now has good low end, mid and very good overrev….100hrs on stock top end & clutch before normal preventative maintenance. Best do it  all bike ever. I can race Gncc one week, remove tank & bark busters & race Mx the next. The TPI transitioned well to the 300”s, appears 125/250 need more development? I have had several KTM 300”s, jetting them was a PITA….they should have left the GasGas 125& 250 carbed with older frame to separate it from premium line models while they continued to work out bugs… With KtM current state, they may never get to work out the bugs….

KTM has been releasing bikes that aren’t quite ready for a long time. My 1983 250mx had a pressed together 2 piece front axle that would come apart if I overjumped something. The first RFSs had incompatible valves/valve guides. 

Don’t buy the first couple years when they come out with something revolutionary. They make it great eventually, but the customer finishes the development sometimes. 

This is exactly what we went through. I’ll also add, my son just completely started not trusting the bike. The 24 stock bike cut out on the finish at 3 palms and I said never again. All 3 went up for sell at that point. I got tired of messing with them. 
I have two 23’s that just sit in the garage, with one that won’t even start. Flat out tired of driving 2 hours to the dealer just for the stocker to get a rescan when a code is thrown. I have a GET on the mod bike tuned by HP and it’s still shit imo. Bike cuts out, you can only rev it so high before it starts the classic bog with these bikes. 

We were KTM guys, but this pissed me off. They dropped the ball on these bikes and literally made the consumer work out kinks. Even from what I still hear, they still haven’t figured them out on the new ones. 

We’ve been on 250’s for a minute now and neither is a KTM make. Honestly, I think KTM makes a great 250, and my son loves the KTM feel, but we didn’t even look twice. We went the Kawi route and couldn’t be happier. 

If I remember correctly, The year the first TBI 125's came out, the entire field at LL was on the older carbed bikes.  I had a 2020 KTM 125 and I got a premium for it when my son moved to 250's full time.

👍

For a loooooong time my motto regarding buying new designs has been, "You first".

Experience can be priceless, no?

Yeah this is huge - our 22 125sx was about 205 lbs wet (spring forks and A60s) and it was a freaking rocket at approx 40hp with a 120 lb rider on it. No one needed electric start and especially 10lbs more on them. Huge miss by KTM.

Jeffro I know you like a nice RM!   The new generation Austrian frame is a lot more Suzuki like in the turns and that’s something I very much enjoy.   Overall my 2024 Mc250 handles great. Tons of front end trust.  It goes right where you look without fuss and has nice balance in the air. 
I agree with Urban that the new chassis alone is worth the upgrade. 

I had a 2019 ktm250sx for a short time that I did not enjoy one bit.  The motor although strong was all bottom and mid with no top or over rev.  If you don’t like reving a bike out maybe the old engine is fine but if you like to rip on top the new engine is superior.  
For me the new Gasgas blows doors on the old engine.  It’s no comparison stock for stock.  Super smooth and absolutely rips on top.  Runs like an old cylinder reed cr250.  Maybe a tad less snappy right at the very bottom.   Plus the new engine sounds great on the pipe.  Super throaty.  
 

If I were to complain about one thing it would be the seat.  It’s a rock!  I’m planning on getting a seat concepts complete seat to fix that issue.   





 

Your 2019 was not jetted correctly.   KTM totally F'd the jetting on that gen bike by spec'ing a way too rich slide and way too lean main.  The long thread on this forum has all the secrets to get the jetting right and it costs less than $150.   When jetted right, the old gen bike, both 250 and 300, absolutely screams on top with crazy overrev.  Way more than the TBI bikes that have a rev limiter and fall flat much sooner.   It's crazy that guys cry about a little jetting but are fine driving to the dealer for reflashes and paying hundreds or thousands for ECU's, etc.

As a former motorcycle mechanic by trade I know how to make a bike run. My 19 was jetted absolutely perfect. I spent hours tinkering.  
I do agree some good progress can be had with jets and slides but for me the old engine is primarily a bottom-mid engine in comparison to the Japanese bikes or this new Austrian gen machine  

I’m not complaining about jetting if that’s what your last sentence is insinuating.I have a few Rm250s and a few CRs that I won’t ever sell.  I actually want to try the stic for them and get them even more dialed.  I also like to tinker with EFI mapping and see it very much same same.  

At the end of the day I much prefer the new gen Austrian machine vs the old one. 
To eaches own mang.   






 

Have a ‘25 125SX here. Been really happy with it. It’s important to make sure the TPS is set properly.  The stock 25 map was generally “ok” and better than previous years. The updated map can be downloaded to the 23’s & 24’s. We got the TSP ERM and it was well worth it, not only for the map(s), but also for setting the TPS and Power Valve reset, all in one easy to use tool. On our next top end, I’ll put on their head, insert and new map for it. Can’t wait. 

I have to apologize for the crying comment.  That was not directed at you but I see it looked that way.   That was more a generic comment about guys making a big deal about jetting.

If you did not swap the slide on your 19 it was not "correct".  Yeah, you can get them running pretty clean, but they are handicapped big time by the stock slide and that is what causes them to be bottom-mid focused.   They are an entirely different bike when you lean the slide out and do all the other mods from the thread in the tech section.  Actually just last week, I had a guy with a 19 ride my bike.  He had the same complaint about no overrev and was talking about getting a TBI bike.  He took a rip on mine and came back and said let me get them specs.. LOL

Glad you love your TBI bike.  Hope it continues to be awesome.

As a former mechanic you should know adding some base gaskets and a little bit of hoarding will change your transfer timing and get all the over rev you need did it to my kids 250.

Agreed! 
I could move some things around but I’m not tearing into a 3 hour bike to do so when I’m short on time..  Im going to wait until it’s due for a topend.   
But none of it matters because I sold the bike due to other traits that I didn’t care for either.  I wanted to like the 16-22 gen Austrian bikes (bought 3 new ones) but I just didn’t gel with them.   
 

The 250 tbi bikes are fine too. It seems to be the 125 that has the most issues. 

The transfer post injected bikes were disappointing.  Good bottom end but died on top.

The newer throttle body injected ones are awesome.  Still good down low but they pull hard on top.  They rev out like the old carb ones.  And the powervalve opening is seamless.

I've got a 25 300 XC and love it.

Sweet 97. How do you stick 3k into a 125 engine?  JM Racing 475 I think deck, port , unique head mod , carb taper bore was extra .  39.9 +  , 19.9 ft lbs instantly offa stab of the clutch.  04 cr125 a Euro topend pipe brings it past 40 hp land. Stock pipe or fmf with a shorty it’s a quick torque rocket.  I think it’s perfect LL track engine or sand . Sitting all weekend no freight in Indiana. I checked lap time s of 125 bc faster than Mike Brown etc in 40+ , 50+.   So all the 125,s r fast now.   I was thinking about 125 c & or 50+ at LL. Because sponsors kick the money to these racers .  My bike is built for regular piston ring hrs . Runs on c12 though.   I can buy it in bulk for aprox 7.50 a gallon.  Planned on racing the 125 class , 40 b for  3 weeks then.  125 class , 40A but there not many , 2-3 30a races  just try to learn the pace , 250a for points .  The 3 consecutive weekends of pro am & the big 2-st races r in the fall.  After LL run the old system 125 c for a national championship. Then turn ProFESHENAL the next weekend .  

Good to hear . Haha . 2nd try to post practice bike pics. Race bike is in a secured vault in a secret location.