Chilly’s Blog – The Silver Bullet

Direct Injection Two Strokes To Save The World

I find it amusing that every time someone decides to rehash some technological idea, the internet world reaches out with a death grip to claim it as the new saviour. Such is the case this week with Cycle World Magazine’s debut of the concept drawing for a Husqvarna direct injection TE300 two stroke. The story spread like wildfire around the online world. Apparently we are to believe that street legal two strokes dual sport bikes are just around the corner.

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Before I go too far, let me say a couple of things

  • What a great picture CW has turned out. This thing looks so real that it alone is enough to have people angry that their local dealer does not already have it on the showroom floor. Full credit to C.G. Design for their artwork.
  • I am all for two strokes, love them with all my heart. I am all for direct injection should it ever come to pass.
  • This is a topic started by Cycle World, but with plenty of influence from Husqvarna. They have been telling anyone who will listen that a DI two stroke is just around the corner. You will notice that the Cycle World story has a nice layman’s recap of the current two stroke and DI situation. This is not a Kevin Cameron type story and discretely sidesteps any talk of the myriad of technological challenges that still lay ahead.

To say that I am skeptical is an understatement. We have been listening to talk of this “silver bullet” for over twenty years. There were the Orbital engine designs out of Australia. At one time, Subaru was going to build a DI car for Asia. Apparently, many have forgotten the fabulous Bimota Vdue that ruined the company. This is not a new topic, yet the current heyday of two strokes has come and gone without a champion to save it.

Will clean burning two strokes make a comeback? Yes, of course they will at some point. All technology orbits around a center and comes back to prominence at some point. In some applications direct injection 2T motors are doing very well, snowmobiles, watercraft and even scooters.  For many, these are the examples cited as proof that DI dirt bikes are just over the horizon.

But if it was only so easy. In fact, now that I think about it, it must be so easy that it should have been done already! Someone must be holding out on us. This must be part of some conspiracy to see XYZ company fail, because of advertising dollars or the internet or magazine editors that are dummies. Maybe it is the big oil companies, corporate greed, off shore tax loop holes or the Democrats.   Surely some nefarious force is conspiring to keep us from the silver bullet.

Well, maybe you get my point. The lack of critical thinking by some amuses me. If it was so easy, it would be done. So perhaps it is actually really hard.  The complex mixing of fuel and air in a competition level dirt bike is exponentially more complex than in something like a snowmobile.

Like most small engines, snowmobiles tend to run at a relatively constant throttle position, often wide open. The nature of the automatic style clutch keeps motor rpms steady and smooths the power delivery. When you see a snowcross rider doing a big jump, it is typically with the throttle in a wide open position. This is the absolute easiest scenario for mixing fuel and air. It  might look similar to what a motocross rider does, but actually it is far from it.

A motocross rider relies on extremely precise and finite actions that come from throttle manipulation. There is no buffer, like the centrifugal clutch, to smooth out imperfections. If anything, it demonstrates just how good the current carburetor technology is. It has taken many years of learning and practice to get four stroke fuel injection technology on par with the good old carb.

It is an excellent analogy for our discussion of direct injection. Fuel injected dirt bikes have been in production for roughly twelve years now. The Cannondale arrived in 2000, the Gas Gas in 2002. By model year 2012, EFI bikes have become more or less universally accepted. But it was just a year ago that models like the Beta 450RR and KTM 450sxf were still considered equal to, if not slightly better, than their EFI counterparts.

I accept that there are some differences here. The first EFI bikes came from small companies and the general technology today is vastly improved. But it still leaves me skeptical to think that an EPA legal dual sport two stroke is just around the corner. We have never even seen a real life example in any form.

For those of you thinking about the OSSA. My information leads me to believe that the enduro bike will sadly never make it to production. With the economic situation in Spain, there is no investment money to move the project forward. As for their current direct injected trials bike, it has seen mixed reviews at best.

Another thing, it seems that anything we do to two strokes, just ends up adding weight to them. Four strokes on the other hand seem to constantly lose weight. Direct Injection technology will bring a whole new range of complexity to the 2T. There will be the fuel injector, the air induction system, possibly a separate oil injection mechanism and  new electronic components. On top of that, it is still possible that a road going model would require a catalytic converter. With the added weight and complexity, the two biggest benefits of the two stroke might well fade away.

Now don’t get me wrong. I am all for this new technology coming to the market. I want to be the first to ride such a bike (although I am not sure I would be the first to buy one). But when you consider the real world challenges that are still standing in front of this technology, it hardly seems like the silver bullet that so many are dreaming of.

There are very few examples of successful revolutions in the motorcycle world, evolution is the path to success. We will probably send a few more years marveling at what a great and simple contraption the keihin PWK two stroke carburetor is.

As for the talk of a new generation Husqvarna with direct injection, as I said, I am skeptical. To my way of thinking, from the day that I see an actual running prototype of anything with totally new technology, it is still a couple of years away from production. I see this as more of a smoke and mirrors display. Something to distract people from the fact that German-Italianos don’t have much else new to talk about in the product line.



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  1. Jim says:

    And….it will make them more complex and expensive as it has done to the snowmobile

  2. David T. says:

    Although I agree on most points. There are some points to be argued the other way. Bombardier’s etec out board motors almost always weigh less then their 4 stroke equivalent and produce a very similar power curve. Yes the constant throttle/load is a valid argument but from a weight point they have the technology to keep the weight bellow or equal to a 4s and you will always have that lighter bike feel from the reciprocating mass. My biggest question is why are they jumping to direct injection. Why not start with fuel injection and go from there? Some guys in Australia have already fuel injected a cr500 in a modern 4s frame! The initial reviews is that it works pretty well and these guys don’t have the manufactures budget to perfect it.

    Fuel injection and electronic power valves would give he ability to greatly tune the power curve of the 2s. I know it won’t allow them to meet epa standards but it would be a step in the right direction while they try to figure out the DI magic bullet.

  3. Jason R says:

    I agree 100%. I might buy this if it was coming from KTM. Husqvarna hasn’t even got the fuel injection right on most of their 4 strokes yet. I think the complexity factor will prevent this from happening in the near future. I think KTM would be the company that could most likely pull it off but what motivation do they have. They already dominate the 2 stroke market. The reason a lot of people are going back to 2 strokes is that they are easier to work on and cheaper to maintain.