Two-stroke fans rejoice, KTM is now officially your savior. While emission standards like the new Euro 4 emissions laws are making it more and more complicated to get a standard two-stroke to pass the smell test, KTM is committed to what put them on the map in the first place, their two-stroke machines. News has circulated for a while of manufacturers developing direct injection two-stroke engines, but nothing has come to fruition until now.
While two-stroke fuel injection technology is obviously available, looking at you snowmobiles, we have yet to see direct injection on any type of power sports engine. But now KTM is bringing us a type of direct injection for their 2018 lineup. The 250 & 300 EXC TPI models will feature KTM’s patented Transfer Port Injection, a type of fuel injection that lends itself to the unique two-stroke operating cycle. KTM claims this new system will make the two-strokes more efficient than their 350 four-stroke counterparts while also producing a similar powerband.
Because of where the fuel will be directly injected into the engine, the new ECU will have much better control over the lubrication system. This will singlehandedly solve the emissions problems two-strokes are known for. KTM has been developing this system for what feels like decades now. Although in reality, it has been just a couple of years. They even tested a couple of prototypes at one of the world’s hardest enduros, the Roof of Africa that took place last December. For those that don’t know, Roof of Africa is almost as hard on the bikes as it is the riders, with an overall elevation gain of 5000 vertical feet. That’s a fairly substantial swing for any carbureted bike, making a DI system sound oh so sweet. It also makes for a great proving ground for the TPI system, trial by fire as it were.
My question is how much will it weigh? While two-strokes have tons of benefits arguably the biggest ones is they are on average much lighter than their four-stroke equivalents. This new TPI system will add in an external oil reservoir as well as a pump to mix the fuel and oil before combustion. On top of that, it will also add in more electronics and injectors. It might not sound like much but all these small parts add up with potential to spoil the light handling that two-strokes are known for. It also adds to their complexity, another characteristic flaw of the modern four-stroke. Albeit the engine will still be a simpler design, any time you add complexity you are taking away from its roots and what made it popular in the first place.
KTM will bring the new TPI models to the public on May 15th, 2017 as a 2018 model year. If KTM’s track record carries any weight we will most likely be looking at the future of two-stroke enduro bikes. A future I am ecstatic about. This move may also prompt other manufacturers to get in the game, hopefully sooner than later. The days of blue smoke two-strokes may be over but as long as the new TPI bikes still brap the same it will likely be just as fun to ride.