EFI for Two-Strokes Is Close!
It is no secret that KTM has been testing fuel-injection on two-strokes for some time. They have been as quiet as possible about it but keen eyes have spotted it out in public. Now at the Roof Of Africa it isn’t being hidden much at all.
Andreas Lettenbichler and Lars Enoeckl have the FI equipped KTM 300s running in a race that has a big variation in both elevation and temperature to shake out the bugs. A great real-world look at how fuel injection can benefit even a two-stroke. The reason for resisting FI has been cost and complexity but times are changing. With new emissions standards coming quickly in Europe and the popularity of the two-stroke world-wide, something has to give. The parts on the bikes, according to people very close, are very production looking. But the could also be sourced from current four-strokes for the most part. The complexity is in the electronics controlling the system. The current two-stroke already has the power to run the system and squirting fuel into an engine through an injector is nothing new. Having a little pre-mix blended in does not cause any issues.
The cost of carburetors is actually increasing to a point where the FI parts may be even less expensive in total. From a production standpoint it is the development time to get the mapping just right that saddles the cost. Two-strokes are said to present some unique issues due to wildly varying exhaust temperatures and differing compression ratios based on RPM and exhaust valve movement–somehow the antiquated carb deals with these issues just fine. Or did they? Time will tell.
The advantages are said to be many. Like increased fuel efficiency, longer power spreads, less loading up and even better throttle response. Some of the “hit” that riders love from two-strokes may actually have to be programmed back into the mapping as that burst is the engine “catching up” to the burst of fuel and air. Sherco has a running FI two-stroke and even Ossa has a production two-stroke trials bike that is FI.
When will we see this? We can not be sure but our educated guess is 2019 for full production from KTM and Husqvarna. Do not be surprised if you see a “special factory edition” type from KTM even sooner. We know they have been working on jetting the Mukini carbs on the current XCWs and SX bikes and that typically becomes less of a concern if they do not need that information for next year.
News about the TPI Two-Stroke:
3 Responses to “Spied: KTM’s Fuel-Injected Two-Stroke Breaks Cover”
The Goat
If this hits the market it will outsell 4 strokes.
Andrew Bernard
What an interesting report and what’s so interesting many years ago i trialed a form of fi back in the late 70s on a 440 maico…in fact I raced it several times as an experiment it was not electronic of course but basically a tube with a butterfly set inside that as opened squirted fuel pre mix …directly into the engine
It actually worked really well and in my recollection tidied up the huge tractor power band and gave amazing response from the slightest twist of the throttle …
We never progressed mainly due to time and the man who invented this was very old and ill and could not commit weekends to play ..
Yes it needed some issues sorting but my knowledge to do this was not great …
I finished my last moto with a win using this system ….the motor did hunt a little after 45 minutes of racing due to running weak …
It was shelved after… but an exciting opportunity for me to work on advanced technology at that time I feel
Graeme Hunt
Well put Keith. The big jap manufacturers knew that pushing their 4 stroke agenda would enable a hike in the cost of the standard bike, plus an increased revenue stream from the sales of engine parts for rebuilds! Development has practically ceased on the 2 stroke from the mid – late 1980’s, the focus was (rightly imho) on suspension & chassis development – then when the big 4 realised that development had reached a plateau phase, the next big thing had to be the competitive 4 stroke!
The 2 stroke is a marvel of simple power/weight and it’s high time that serious development on that ‘spark injector’ you mentioned got started! When do you want to get going??