Yes, there are - and they are busy getting paid to race other machinery. Knowing the top three riders I do not think that anyone without a current ride could get a legal Sportster or the Monster on the podium.
It's not MA. MA lists the eligible bikes. It's up to the manufacturer to homologate the bike for the class. You should call Honda and ask them to homologate that 30 year old dung heep that you have in your garage..
http://www.motoamericaregistration....MotoAmerica Twins Eligibilty List 4.03.18.pdf Listing of MotoAmerica machines eligible for 2018 Twins Cup TWINS CUP MODEL PRODUCTION PERIOD AS FROM - UNTIL Ducati Monster 797/797+ JAN 2017- PRESENT (pending) Harley Davidson Street 750 Harley Davidson Street Rod JAN 2014- PRESENT (pending) Harley Davidson Street Rod JAN 2017- PRESENT (pending) Kawasaki Ninja 650 JAN 2012-END (Complete) Kawasaki Ninja 650R JAN 2017- PRESENT(Complete) KTM 790 DUKE JAN 2018- PRESENT (pending) Suzuki SV650 S/A JAN 2003-END (Complete) Suzuki SV650/A JAN 2016- PRESENT (Complete) Yamaha FZ-07/MT-07 Yamaha JAN 2013- PRESENT (Complete) Yamaha XSR700 JAN 2018- PRESENT (Complete) *Pending homologation
If it says pending, they are not homologated, if it says complete, then you can grid up. the bikes are not legal for the class
But why would they? Why not put that same time, effort, and money into a bike that isn't an underdog...and make it a winner? Just about anything can be made decent with enough money, time, and effort. Seen the dude hauling ass around The Dragon on a Goldwing? IIRC, he has more money in setup and suspension on that bike than the MotoAmerica SBK frontrunners. So sure, it can be done...but why? Just so someone can say "I finished 9th on a bike that most consider a piece of shit". My response would be, "yeah...but you finished 9th...that other dude spent half as much money and won".