I’ll be honest I don’t have much intention of taking this super far at this point, but figured I’s share what I whipped up real quick… It’s a bit of a sprawling mess before I’ve even dumped what’s in my own memory.
Introduced in 2012 to replace the 2-stroke 125 class, the Moto3 category is composed of 4-stroke engined bikes with a maximum cubic capacity of 250cc. Cylinder diameter is limited to 81mm and engine revs restricted to 14,000 rpm. The electronic management system is the same for everyone and engines must not cost more than 12,000 Euros. As in Moto2, each rider has just one bike. Tyres are supplied by Dunlop and limited to 9 fronts and 9 rears. The minimum weight for the rider and bike combined must not be less than 152 kilos. The maximum age of riders is 28.
Karting isn’t controlled by major engine manufacturers like Honda hence why we’re still 2-stroke and dirtbikes/Moto2/3 aren’t. Well dirtbikes still technically allows them, but the elite classes are heavily regulated to favour 4/s (2x displacement allowance)
There’s also a cost aspect, the shift to 4 stroke made costs baloon in dirtbikes. GP I’m not sure compared to 2 stroke, but a moto3 in race spec I think is just under $100K, the base bike is about $60K alone (KTM). Base bike vs base bike, way more expensive today than a 2 stroke Aprilia RS250 or Suzuki RGV, even adjusted in today’s money
Also, since we are talking innovation…I’m really familiar with the shifters so notable engines I think are the Debei Exigo (built from billet), Ryger Revo (due to the whole ring-less piston system) and the Modena that was the first (I believe) to adopt gearbox cooling.
I’m not an expert on the single speeds, but looking at the list the Mugen (Honda) engine I though was a pretty interesting design. What are the others you would highlight as crazy/innovative designs? @Alan_Dove ?