Found this site via the BMW forum I'm on, these guys seem very very knowledgeable on 'Busa gearboxes, which AFAIK are similar if not the same as on the 1402
UcO0TlXE5MI
Only issue is they are in the USA so postage will be a killer
I think I recall 'busa parts are used to upgrade 14s.
I believe you're right Hooli, the output shaft on the Busa is a solid one as opposed to the 1400 as a hollow one.
Quote from: Eric GSX1400K3 on Friday, 29 April 2022, 12:16 AM
I believe you're right Hooli, the output shaft on the Busa is a solid one as opposed to the 1400 as a hollow one.
I,m not sure about all Busa models but I recall early years gearbox shafts were not solid. You're right though that there is an upgrade from APE bike parts(USA??) to a solid shaft which does fit the GSX1400.
I hope i never have to use them, slipping over 7k in 2nd did he say? I can understand that on Busa. My bike howls a bit in 1st, never worried me, never changed. Is that a common 14 thing?
Yup. 1st is straight cut gears as they can handle more power, it does mean more noise though hence the rest aren't. I forget the name for the rest of the gears, but they are slightly 'not square' across the cogs to reduce noise, if memory serves.
Correct, 1st is a spur gear, the rest are helical cut gears. Spur or straight cut gears transmit more torque but generate noise because it's line contact across the gear face. Typically used in race cars / bikes where this noise doesn't matter as much. Means a smaller or more compact gearbox can be built. Helical gears on the other hand are rolling contact, hence less noise and wear, but need more face width to transmit the same torque.