What is the difference between a 3 & 4 speed gearbox?

What is the difference between a 3 & 4 speed gearbox? Harley Davidson WLA / ep240 How to restore your Harley - the bible we use: https://amzn.to/30xSt1y All the music we use comes from here: https://bit.ly/2X5v59w Join us on Instagram for regular photos   / riestoreltd   Our website: http://rie-store.com/ All business enquiries to stuart@rie-store.com Weekly series documenting our work, plus hints, tips, tricks and Q&A. Subscribe now - New video EVERY FRIDAY. To have your question answered please use the hashtag #askash in the comments.