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KTM Introducing Fuel Injected, Two-Stroke Enduro Bikes

KTM still manufactures two-stroke dirt bikes, of course, but today announced that certain 2018 models will be fuel injected. KTM claims “drastically reduced fuel consumption”, and other benefits described in the following press release.  Note that these new models appear to be off-road only, and there are no claims regarding emissions.

KTM is pleased to mark a major global milestone by announcing that it will unveil the world’s first serial production fuel injection 2-stroke Enduro machines at an official launch this coming May. The KTM 250 EXC TPI and KTM 300 EXC TPI models will be introduced to the global market as part of the model year 2018 lineup, while the 250 XC-W TPI model will be introduced to the U.S. and Canadian markets.

The Austrian manufacturer is well-known for its revolutionary advancements in technology and now the game-changer is finally here with 2-stroke fuel injection Enduro models being launched as part of the 2018 EXC range. With KTM’s unwavering commitment to being at the very forefront of offroad motorcycle sport, in which the orange brand has achieved many championship wins over the years, the latest, exciting development in technology has come to fruition.

It has been no secret that KTM’s Research and Development department in Mattighofen, Austria has been developing this technology, which offers considerable benefits over carbureted models including drastically reduced fuel consumption while also no-longer having the need to pre-mix fuel or alter the machines’ jetting. Not only that, the new 2-stroke TPI models offer a completely new experience in terms of power delivery and rideability, which once again demonstrates KTM’s commitment to its offroad roots, continuing on from the all-new generation of Enduro machines released last year. As market leaders in this segment, KTM believes the new 2-stroke fuel injection technology, known as TPI (Transfer Port Injection), is revolutionary. More information will be available during the international media launch, which begins on May 15, 2017.

Joachim Sauer, KTM Product Marketing Manager: “This is an incredibly exciting development for KTM. We have been developing 2-stroke fuel injection for some time and our goal was to create competitive motorcycles with all the benefits of fuel injection, while fitting into our READY TO RACE mantra. There has been extensive testing and considerations for our Research and Development team to take into account during this process, so we are very motivated by this next step and world-first in technology, as we take a major step forward in this segment. We are certainly looking forward to unveiling the new 2018 KTM 250 EXC TPI and KTM 300 EXC TPI machines in May. In Europe the bikes will arrive at the dealer floors in early summer, and in the U.S. and Canada, the new 2018 250 XC-W TPI will be available in very limited quantities in late fall.”

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  1. FNFAL says:

    Damn that engine looks cool – like a mini nuclear reactor! Riding a 500cc two-cycle MX bike back in the day was exhilarating to say the least.

    • Dirty Bob says:

      Yeah the BSA 441 (single two stroke) was fun and powerful. Yet even with compression release my leg still gets a twitch when I dream of the bike.

  2. MikeG says:

    I’ve always thought that using a small amount of oil, highly diluted by gas, for the sole purpose of lubricating the crank bearings of a two stroke was a large engineering compromise that they’d eventually solve. While this press release doesn’t mention it, is it possible they simply have crank bearings bathed in their own oil supply and still use a sealed portion of the crankcase to facilitate normal two stroke air induction, with a shot of pure gas via a combustion chamber injector? That seems to me to be the most obvious fix.

    • MGNorge says:

      That oil was included in the fuel-air mixture was part of the simplicity of a 2-stroke. But yes, for emissions concerns, oil has to be kept out of the combustion chamber and exhaust or it poisons the catalyst. This then opens up the design to incorporate an oil supply to lube the bottom end. An oil control ring would also be needed on the piston.

      • Norm G. says:

        re: “for emissions concerns, oil has to be kept out of the combustion chamber”


        re: “An oil control ring would also be needed on the piston.”

        ship it.

        • Dave says:

          I don’t know how effective an oil ring will be if it passes the open sleeve ports, every cycle.

          • Norm G. says:

            re: “I don’t know how effective an oil ring will be if it passes the open sleeve ports”

            me neither, i’m just the visionary, you guys are the nuts and bolts… (Homer J voice)

            no in all seriousness not that it’s definitive, but one may want to simply TRY combining the old rodder’s trick from 4T of vacuuming down the cases to assist with this (hint, a modern application can be found in the Ducati Superquadro). oh and it only need be a port (singular) not ports (plural) as would be 2T “conventional wisdom”. naturally multiple voids would be problematic and self-defeating. the good news…? drawing a vacuum potentially adds power to this equation and the Laws of Physics dictate high pressure always moves to LOW pressure (and anything along with it) it’s what it do. the bad news…? well there’s that whole weight thing i mentioned of another added accessory. see, no free lunch. of course then this begs the issue…

            Q: if you’re also using forced induction (or scavenging) do you really even need to continue with positioning the “air hole” somewhere’s low on the cylinder wall…?

            A: dunno.

            just saying, normally aspirated 4T’s running at high RPM seem fairly capable at filling their cylinders on valve overlap. think MGP and F1 (no not turbo era but the shrieking V8’s/V10’s, you could’ve had one).

      • Dirty Bob says:

        Don’t over think the design. Let the oil blow through. One cannot duplicate the wonderful smell and smoke it give off. Like burning trash!

    • Jeremy in TX says:

      I suspect simplicity and less maintenance are two attributes that are important to the 2-stroke consumer. I know it is important to me. As such, I seriously doubt KTM would go with a no-loss lubrication system.

      Two-strokes exist in other industries that separate induction from the crankcase. The solution has existed for nearly a century.

  3. mickey says:

    even if they did make another street 2 stroke, it would probably have the crouching tiger, saggy boob head light, wasp stinging tail look nobody wants lol

  4. Mr.Mike says:

    Maybe last big refinement of the internal combustion engine before everything goes electric?

    • MGNorge says:

      I guess we’ll see but my hunch is no. From some articles I’ve read, the expense to manufacture these high-tech 2-stroke designs equals or exceeds that of building a 4-stroke.
      We may see some come into the mainstream but I’d be very surprised if more than just that.

  5. Norm G. says:

    re: “More information will be available during the international media launch, which begins on May 15, 2017”

    BRING IT…!!! (no, that’s the sound of 2-stroke silly)

  6. Jeremy in TX says:

    Honda filed a patent for a direct injection 2 stroke a couple of years ago. I wonder if this intro from KTM is the first domino for a revival of the two stroke market.

  7. CrazyJoe says:

    2 stokes? I was thinking for direct injection high compression without spark plugs gas 4 stroke. Like its 2017 not 1967 man. Can’t wait to see the cost of either design.

  8. ChrisRR says:

    If KTM puts the technology in its SX line perhaps the AMA will finally be compelled to abolish its totally unfair regulation which forces 250cc two strokes to compete against four strokes of 80% more displacement, effectively banning them from competition.

    • Retep says:

      Will never happen, 2 strokes self-supercharge because of the way they work, resonance. So more development is needed to get more usable performance from them, and thats the difference between the 2. Shut the throttle on a 4 stroke and automatic braking, nothing on a 2 stroke, instant torque on a 4, little on a 2. But 2 strokes are lighter so handle better. In the right hands they are equal

    • Dave says:

      A 450 4t has 200cc more, but it fires 1/2 the number of times per minute at a given speed. It also weighs 30+ lbs. more. It’s not unfair at all, it’s just exposing the shortcomings of 2-stroke power production, which was apparent almost immediately after Doug Henry began campaigning the 1st 4-stroke Yamaha.

      • ChrisRR says:

        Shortcomings of 2 stroke power production? Dude, a 450cc 2 stroke would eat a 4 stroke for lunch and excrete the remains out its stinger! A bunch of hacks pass a law and the minions swear by it, SMH

        • Norm G. says:

          re: “a 450cc 2 stroke would eat a 4 stroke for lunch and excrete the remains”

          a 2-stroke’s got CHUNKS bigger than any 4-stroke in it’s stool…!!! (Phil Hartman voice)

        • Dave says:

          Re: “Dude, a 450cc 2 stroke would eat a 4 stroke for lunch”

          We’ve seen that before. Do you not remember 500cc 2- stroke mx bikes? More often they are their riders for lunch, and went around a track no faster for it..

      • Norm G. says:

        re: “the shortcomings of 2-stroke power production, which was apparent almost immediately after Doug Henry began campaigning the 1st 4-stroke Yamaha.”


  9. mkv says:

    CA green sticker right???

  10. RD350 says:

    Think of the road possibilities.
    RC300 TPI or Duke 300 TPI …. or a SuperMoto 300 TPI … or DualSport 300 TPI.
    If they are street legal in the USA, I pledge to buy at least one, if not one of each.
    Go KTM!! .. the coolest manufacturer today by far. Bring on the Return of the 2-stroke!

    • Jeremy in TX says:

      Let’s not kid ourselves, here. I don’t think we are ever going to see a street-legal modern two stroke that isn’t a plated dirt bike.

      • RD350 says:

        Never say never. They CAN make them run clean. All of the positives .. lighter, cheaper to produce etc are still in play. I predict that, like all things, they will come back into fashion one day. Hard to predict just when. There is certainly a market for them now. Those of us who grew up on the things (and there are many of us) are in the right demographic, right now and are ready and able to spend real money. Young riders who have heard the tales will also be lining up .. especially if the power/dollar ratio is right. It would be great for the sport. I’m hopeful anyway.

  11. dt 175 says:

    wonder if it’s worth two seconds a lap to smith and kallio…

  12. redbirds says:

    Love the old road going two strokes. I hope advancements in emission technology will allow their return.

    • spokes says:

      The “advancements in emission technology” have been available for years. The eviro freaks will never let them happen for road going vehicles. Snowmobiles and outboard motors have some very clean two strokes but the bleeding heart liberal enviro freaks in the EPA will never admit it.

      • RD350 says:

        A Trump EPA might not be so dismissive of technologies that would have triggered Obama-era EPA snowflakes to run to their safe spaces. Timing might be just right actually! MMGA (Make Motorcycling Great Again!)

      • chase says:

        Well…. the EPA is being hollowed out as we speak because of overreaches on small potatoe issues like this and playing politics. Payback is a bitch.

      • Dave says:

        Clean or clean”er”? These still must burn oil in their fuel mix. I haven’t seen/heard of a direct emissions comparison to road legal 4t stuff, not that it hasn’t been done. If it has, I’d be interested to see the results.

        We have to remember that 2stroke didn’t go away because of the EPA, it went away because 4stroke yeilds Superior (torque, power, rideability) performance on motorcycles. Road motorcycles went 4 stroke long before the EPA mandated it.

        • todd says:

          Dave, that is false. The RZ350 for example makes 36 lb-ft of torque whereas the CB350 makes 18. Both produce those peak numbers around 9,000 rpm.

          The myth started when all those little 250 and 350 twins were blowing the doors off 1,000cc twins. Comparably, yes, those 1,000cc twins made more torque but weren’t any more powerful…

          • Dave says:

            Can’t compare with like displacement. The 2t fires twice as many a given crank speed.

          • Mick says:

            Sorry Dave,

            You can’t get spotted a bunch of displacement just because you have a garbage technology. Four strokes don’t have huge holes in their cylinders that open for half of the power stroke. You seem overly happy to overlook that. Take a look at the outboard boat motors and snowmobiles. You want light weight, more low RPM torque and more power for a given displacement with better emissions. You buy a two stroke. Game, set and match.

            The 500cc two stroke motocross bikes went away because they stopped being developed in the early 80s just after they first received water cooling. The Yamahas never even got that far.The KLR650 engine is never than the most recent 500cc two stroke. And it is a dinosaur.

      • JSH says:

        Snowmobiles and outboard motors a also regulated by the EPA but the allowed pollution levels are higher than for road legal vehicles.

        If a two stroke engine can meet road emission standards the EPA won’t have an issue with them. It is a binary choice: Does the engine meet the standard or not? Today two-strokes do not.

  13. JBFST says:

    Remember ,, never buy the first model year of Anything

  14. Rapier says:

    4 strokes have become so light and compact that 2 strokes probably only make sense in ultra high performance applications. I am sure many will disagree. Yes marine and snowmobiles have had direct injection 2 strokes but because they don’t have direct drive, so to speak, they do not need precise linear throttle control like cycles do. If KTM can master that they why not I suppose. Will it be cheaper to build? How about reliability?

    • todd says:

      The two-stroke motor, when not tuned for maximum peak power, makes tremendous torque for its capacity.

    • PatrickD says:

      4 strokes are far from the low-maintenance nirvana that they were percieved to be. Japanese 4T motocrossers are really hard to keep running and require regular expensive overhauls.
      There’ll be alot of long-running MX guys who would love a return to the 2T days.
      KTM are being such great innovators these days. Honda especially are hiding in their turtle shells when it comes to innovation and inspiration.

      • Chrisgo says:

        the cost of maintaining a modern 4 stroke MX bike has really hurt the industry. I wouldn’t buy one because I can’t stomach the top end rebuild costs. By comparison, I rebuilt the top end of my KX250 (2T) for under $150. Even a crank rebuild (after a blowup) was ~$800.

        • TF says:

          They’re selling plenty of four stroke MX bikes and they’re selling more parts and service than they use to. I wonder if the change to four strokes has really hurt the industry. It’s starting to look just like the auto industry…..constantly designing in content to raise the price and the margins. Now they just need a leasing program for motorcycles.

    • spokes says:

      “precise linear throttle control” Sooo… You think a KTM EXC 250 with a carb has more precise linear throttle control than a fuel injected one??? Keep drinking the Kool-Aid partner!

      • GKS says:

        Perhaps you don’t recall the complaints about abrupt throttle response when the 450cc motocross bikes went to EFI. Or the same issues with EFI on streetbikes (some of which still linger on).
        Of course EFI has it’s advantages, but carburation has many decades of development and testing behind it.

        • Jeremy in TX says:

          Both systems need tweaking to optimize a particular bike for certain set of conditions. Personally, I’d rather do my tweaking with a computer. Both systems can work brilliantly, or they can work terribly depending on how good the setup is.

  15. GSJim says:

    So does North America get all 3 or only the 250 XC, not sure by the wording, looking to replace my current off road mount in the next year or two so the timing looks about right. The “others” need to step up to the plate, they are getting left in the dust (mud)

    • Provologna says:

      “…250 XC-W TPI model will be introduced to the U.S. and Canadia…” What’s not clear about that?

  16. johnny ro says:


    Outboard 2-stroke boat motors have had direct fuel injection for a long time and it works fine. Some include mild forced induction for scavenging.

    I think could be hooked to a cat and be road able.

    • Pacer says:

      I am not sure how much the technology has improved, but direct injection wasn’t a good fit for motorcycles. Direct injection engines did not do well with constantly changing rpms. I figure with all the ride by wire/computing power now common they would be able to address this. At least I am hoping they will.

    • GKS says:

      The addition of “TPI” fuel injection will not fix the inherent emissions issue of a 2-stroke. That is, some of the as yet unburned air/fuel mixture exiting the combustion chamber before the exhaust port closes. This is why direct injection has been the “holy grail” for emissions legal 2-strokes, the fuel could be injected AFTER the exhaust port is closed.

      • Denny says:

        Makes sense; good information. Thanks.

      • Dave says:

        There is also the unavoidable oil-burn. I don’t know if catalysts exist that can address those emissions.

        Even if this doesn’t result in the return of road-legal 2T’s in the US, many off roaders will appreciate the simplicity offered over the 4T and expensive head maintenance.

        • blitz11 says:

          I did the math once. My buddy had a BMW GS1150 which burned a quart of oil every 600 miles. I ran my GasGas 300 on Amsoil at 50:1. I burned less oil per gallon of fuel than he did, and his catalyst was fine.

          A roadable 2 stroke is entirely possible, but the number of people who would want one is probably so small that the development costs could not be justified.

          I’d have a two-stroke street bike in a heartbeat. Nothing beats a 2 stroke dirt bike, either.

          Most 2 stroke oil burn is particulate, which settles, and really doesn’t kill air quality in the long run. Unburned hydrocarbons? Another story.

        • Norm G. says:

          re: “There is also the unavoidable oil-burn”

          therein lies the rub. DI for all it’s “second coming” benefits still only addresses 50% of the emission equation as far as EPA regulators are concerned. ya gotta remember with 2-strokes there are/were two parts, while it’s certainly been a great step, injecting fuel after the ports are closed DOES f#%k-all to address the fact (even with targeted lubrication) that it’s still essentially a TOTAL LOSS oiling system relative to 4T, this is no good.

          now if we look at what Detroit did with 71 series 2-stroke diesels waaaaay back in the 30’s, you crazy kids can actually still have 2-stroke power however (comma) you have to be willing to give up the simplicity everyone and their nana has come to mentally associate with 2T design. but is that really a “dealbreaker” now that you’ve been conditioned to accept the relative complexity of 4-strokes…?

          example… (Jules Winnfield voice)

          71’s because they couldn’t normally aspirate, had to be mated to a supercharger just to start and run. something they ALSO had instead of using traditional weedwacker/chainsaw cross porting, they used both cylinder porting in COMBINATION with overhead valves (yup same as 4T). in this instance the cylinder ports were dedicated solely to intake, and the OHV performed strictly an EXHAUST function. another benefit is this switched the gas flow vertical/longitudinal forcing travel over a longer distance helping reduce the chance of intake charge exiting the exhaust port stage left like you have with a normal cross flowing tuned pipe/resonance system.

          Q: wait, what are you getting at Norm…?

          BETTER Q: think out the box, who told you the ONLY way to deliver air to the cylinder ports of a 2T engine is via an oil contaminated crankcase, when you already damn well know a 4T doesn’t get it’s air this way…? and the oil in a 4T’s crankcase is (for all intents) acceptably SEALED OFF from the combustion chamber…? ok, i therefore contend the so called “oil-burn” is completely AVOIDABLE.

          Q: how…?

          A: you’ve already done it.

          gentlemen you’ve just been given a possible solution to high output, clean burning, road-going 2T power. now it won’t be as light as you hope, but you’ll have power akin to a 4 lobe 20B Rotary without that whole pesky spitting of apex seals thing (holy crap that’s alot of power). right, i’ll be along to collect my fee shortly.

          • Half Baked says:

            Seriously. 400+ words. I stopped after, “therein lies the rub.” At least that was funny.

  17. Stan Gale says:

    Turn it into a 500cc VTwin for the street and you have a Bimota V-Due 500 that works! (20 years later…) Put it into the 390 frame and we’ll all be happy.

  18. Jeremy in TX says:

    Fuel injection? 2-stroke? What’s not to like?

  19. TF says:

    Can’t wait…..time for an upgrade! What will I do with my jet collection?

  20. patrick says:

    I have been waiting for this for a couple of years since reading that someone in Europe was working on a fuel injected 2 stroke. The project then was to include an oil pump to oil the crank thereby eliminating the need for gas/oil mix and meet emissions requirements for street bikes. I see that KTM is indicating there is no need to use pre mix. Does this mean that they have gone all the way to make a “clean” 2 stroke or is there an oil pump feeding the injector?

    • Mike Johnson says:

      Idea would be to just use the crankcase to pump air into the transfer port where only fuel is added at the injector. Has to be a separate oiling system for the lower end tho-some way to scavenge excess oil from the bottom of the crankcase to keep it as *dry* as possible.

      • GKS says:

        Beta 2-strokes have used computer controlled oil injection for a couple of years now. I am not sure if their system feeds the crank bearings directly or if the oil is simply injected into the intake port like the old “Yamalube” system.

        • Norm G. says:

          re: “Beta 2-strokes have used computer controlled oil injection for a couple of years now. I am not sure if their system feeds the crank bearings directly or if the oil is simply injected into the intake port”

          Texas Jeremy, talk to us Goose.

          • Jeremy in TX says:

            The oil is injected into the intake manifold just downstream of the carburetor. Everything else is standard two-stroke business as usual. You could disconnect the pump, plug the oil injection port and run premix with no issues if you wanted

            I can’t decipher KTM’s marketing speak, but I suspect they are actually going to use throttle body injection. I am sure they will likely spit the oil into the fuel stream in the manifold directly behind the throttle body just like the Beta.

  21. Tom says:

    As a dyed in the wool 2 stroke lover I say hallelujah! Helloooooo Japan incorporated (cricket sounds).

  22. blitz11 says:

    Wow, a big step. Great timing – i just rejetted my GasGas and daughters’ KTMs for our new 5,300 foot altitude (up from 700 feet). Had this been available a few years ago, i could have saved myself some time.

    It will be interesting to see how these price out compared to the carbureted versions.

    • Steve Bradshaw says:

      Around $20,000 if the United States Trade Representative gets his way.
      Google “bikes for beef”

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