That's odd,I used to race shorttrack and halfmiles and quarter miles back in the day,mid 70's into the early 80's till flattrack died here.
On a halfmile the twins always smoked all comers,usually some combination of RD/aircooled roadrace parts Yamahas. Granted a person would have to know how to build and ride a twin but they are FAST.
Randy Mamola (as a kid) used to show up with 3 bikes,a mechanic or two,and his dad. 3 bikes that matched perfectly and done up to a T.
His Yamaha twin was a rocket,as were all of the expert/pro class twins.
Those twins made the neatest sound flying down the straights and lighting it up off the corners,I suppose a 360 single would be simpler,they always sounded like they were on the verge of blowing up trying to hang with the twins on a half mile.
Some bikes around at times