I have a nice little '74 Yamaha MX175 that I want to set up like a vintage trials bike, just because it's here and paid for. It currently has stock 14/47 sprockets; I don't know the transmission gear ratios. New sprockets are still easy to find and I can get fronts in 12, 13, 14, 15. Rears available in 55, 54 and smaller. Can you suggest a sprocket combo that would be good for playing around my property with small features and steep hills? Then I'm just gonna put on some decent trials tires, rebuild the forks and go have some fun.