Before you build anything you should look and see who all is running locally.
ATV hillclimbing is all but dead because the AMA refuses to make the clubs run the classes I proposed and were passed back in 2012.
D23 up in MN/WI has three riders left because of it. The WV area seems to be slowing too.
There were no more than 10 total ATV riders at Nationals this year.
I just hate to see you spend a fortune to go out and race stock bikes.