This is a nice museum, it’s not huge but has some great displays, plenty of motorbikes, and (when I visited) a Guy Martin exhibit including his first car, his race bike, the Royal Enfield he bought for his TV show and the downhill racer he crashed so dramatically trying to hit 90mph.
A worthwhile visit in an area with some great biking roads - head up through Glenshee and Balmoral, visit Aberdeen, ride the NE250 coastal roads and see some great castles too.
Helpful hint: if you are asking for directions locally, Alford is pronounced Afford! 