There we go. That’s what I wanted to get going.
And yeah I don’t see this as an interest in 206. But the 30hp classes is where I was thinking.
and lastly I’d love to see if they could do a 4 stroke that could compete in TAG. Be really cool to watch the different power bands and which teams choose what.
There were actually a handful for the TaG class. OHC design, 250cc. SA250 was the most popular one. I went to search the web for more info and found a KP topic 
But they never really took off in the US.
Interesting. I’ll look into them. Just out of curiosity.
Edit. I guess they sound awesome. Looking for sound clip now
Riley (BRC) is local to me, they do some crazy cool stuff. Talking on the biland did one not win tag at skusa one year? They posted a recap video last night of I think it was 2006
I was getting deja vu.
This won’t happen, karting will jump straight to electric. The only manufacturer I thought might do it would be Rotax, as they have the direct injection tech already with Evinrude. But they are going down the electric route.
If you were selling 10,000 of units or could make use of an injector from a mass produced bike/snowmobile/jetski, I would estimate (just from my experience working in the manufacturer of diesel engines) that you could get the injector down to sub $50. But I can guarantee karting manufacturers would sell them $200 because a carb costs a similar amount (or more).
TM went fuel injected with the dirtbike range this year, but the reality is that in terms of a karting application it is incredibly unlikely to come in. We’re with carbs until the end of 2-stroke karting. I doubt the FIA will mandate it, and there’s little appetite in the market placed for a shift over in the recreational classes.
That is may be why timing is important. That becomes effectively direct injection.
I looked at this last year in some detail. Besides KTM, which wouldn’t sell me an engine directly, there were no other 2-stroke FI suitable engines for kart road racing. Really, FI makes the most sense with 4-stroke engines, something I can see karting and other 2 cycle sports being pushed towards as states also start cracking down more on all 2-stroke engines.
To get good low end torque out of slow corners AND high end performance with a 4-stroke, FI really helps. And it’s much simpler to meter since standard wideband O2 sensors and controllers can be used due to the lack of oil in the exhaust. Yes you need a small high pressure fuel pump, an injector, O2 sensor, computer, and a small battery to run it. Most of the weight added is in the engine with the valvetrain. So heavier and a little more expensive for the same power than a 2-stroke, but with a start and just run it experience like a 208, even on the coldest days.
And yes, I’d love to go there. A 449cc Kawasaki engine on a kart is something I may just build this year even though I’m not allowed to even provisionally kart “race” it due to nothing bigger than a 250cc engine insurance regulations allowed. 52.63 hp at 9,480 rpm and 32.80 pound-feet of torque at 6,730 rpm on pump gas should provide a lot of grins for the money, even if it has to be at the drag strip.
Typically this is the four stoke limit, although it will vary. There are CRF450’s out there running and racing.
Following up on the two stroke discussion… here’s some thoughts from the 2 Stroke Research and Development FB group. One noteable thing is that I don’t think any of these are regarding smaller 125cc engines revving to 15-16,000 RPM.
Nathan Coleman Injection time, consider injector open and close time not just the deadtime. Multiple injectors problem solved.
Consider effect of the exhaust on the airflow, tuned exhaust can increase inlet port airflow by up to 4x. Consider the exhaust is only active after combustion and that at small throttle positions combustion is irregular. Extremely dynamic air flow, need a sensor for it to compensate fuel on a per cycle basis… difficult!
Derek Laporte I run a turbo 2 stroke efi 1200cc twin with standalone vipec m800 ecu started with a base tune and worked from there it’s relatively easy when starting with a base tune it was way off but only took a day or 2 to come around on the dyno to come around and get it all mapped my friends at d&d Racing have done quite a few in the last few years and taught me how to use the program etc. We also did an efi twin 800cc with a stand-alone as well last summer I love efi 2 stroke and they work great but keep in mind these were efi from the factory we just swap out ecu to have full access and control of everything
Valery Rutkovskiy
I produce programable ECU http://www.flame-power.com/en/direct-en/programable-ecu-en and install it on my 2-strokes. Its programable, so you can adjust behaviour. Stihl have very clever fuel injection with minimal ammount of sensors. One man adopt Speeduino for 2-stroke. Whole history at kiwibiker forum.
Cédric Patouillet For me, it has been not as difficult as expected. The thing is just do your own experiments. For some reason the injector flow has to be way higher than the theory. So monitoring your duty cycle is important !