So, I'm cruising to work this morning and as I cycle through the gears I get to wondering - why does the gearbox on a Big Twin make that distinctive "clack" sound when shifting?

Is it the length of the shift linkage? The sheer size of the cogs? Some obscure engineering decision? As far as I know, only Harley's have such a loud gearshift.

Why is this?

 

Good question, I'd like to know the answer myself. Especially first gear ... no matter what you do, that first shift after starting is loud enough to wake the neighbors.

 

I suspect that first shift of the day is so loud and violent because the oil in the box isn't up to temperature and hasn't circulated properly.

 

Put 85/140 gear oil in the tranny and it will shift smoother and quieter.

 

It's not a problem..It's a feature! You know it's in gear. If it bothers you that much to go from neutral to 1st. Hold the clutch in for a few seconds. Won't make a sound.

 

Its the primary chain tightening when you put it into gear. Its the tried and true 1903 Harley technology we all know and love.

 

It doesn't bother me - I actually like the very positive and mechanical nature of the shift. But compared to other manufacturers, Harley's gearshift is loud.

Just wondering why, is all. I remember the Suzuki's I learned on had a very quiet shift. You only knew you'd changed gear because the lever stopped moving. Perhaps that was because the lever was directly connected to the outside of the gearbox, rather than via a fairly long linkage.

 

Harley-Davidson - 108 years of startling your neighbours first thing in the morning!

 

Actually I think its a CLUNK, not a CLACK.

 

yeah...

put me down for the CLUNK... it's not a CLANK.