Kinda wondered about that too, I thought the clunk was a transmission thing. And as I stated, my goal is to cut down primary noise and that's why I'm trying the R/L Primary oil.
No Clunk
Road Master
Joined: Jan 2015
Posts: 1,057
Likes: 10
From: SF Bay area
The klunk is the sound of the "dogs" on one gear sliding into the "holes" on the next gear over in the transmission. More or less.
BUT, what causes the klunk into first is the clutch. Ideally, the transmission mainshaft that goes to the clutch shouldn't be spinning at idle. The transmission isn't, so the dogs slide right in silently. Think about when you shift into first with the engine off... no klunk.
In reality, even though you disengage the clutch, the plates stick together with the oil film between them, and if the engine is idling at 1,000 rpm, the mainshaft is turning at 1000 rpm... there's no resistance to stop it. Shift into first and the gear (dogs) on that spinning mainshaft have to slide into the holes on a stationary gear, and go from 1000 rpms to zero in an instant.... KLUNK.
The solution is to find a lube that prevents the disks from sticking together. Different lubes seem to work for different people. For me, nothing beats synthetic ATF. My advice is try them all, see what works for you.
Oversimplified to be sure, but that's the gist of it.
Stellar HDF Member
Joined: Dec 2013
Posts: 2,199
Likes: 282
From: Long Island NY
The klunk is the sound of the "dogs" on one gear sliding into the "holes" on the next gear over in the transmission. More or less.
BUT, what causes the klunk into first is the clutch. Ideally, the transmission mainshaft that goes to the clutch shouldn't be spinning at idle. The transmission isn't, so the dogs slide right in silently. Think about when you shift into first with the engine off... no klunk.
In reality, even though you disengage the clutch, the plates stick together with the oil film between them, and if the engine is idling at 1,000 rpm, the mainshaft is turning at 1000 rpm... there's no resistance to stop it. Shift into first and the gear (dogs) on that spinning mainshaft have to slide into the holes on a stationary gear, and go from 1000 rpms to zero in an instant.... KLUNK.
The solution is to find a lube that prevents the disks from sticking together. Different lubes seem to work for different people. For me, nothing beats synthetic ATF. My advice is try them all, see what works for you.
Oversimplified to be sure, but that's the gist of it.
BUT, what causes the klunk into first is the clutch. Ideally, the transmission mainshaft that goes to the clutch shouldn't be spinning at idle. The transmission isn't, so the dogs slide right in silently. Think about when you shift into first with the engine off... no klunk.
In reality, even though you disengage the clutch, the plates stick together with the oil film between them, and if the engine is idling at 1,000 rpm, the mainshaft is turning at 1000 rpm... there's no resistance to stop it. Shift into first and the gear (dogs) on that spinning mainshaft have to slide into the holes on a stationary gear, and go from 1000 rpms to zero in an instant.... KLUNK.
The solution is to find a lube that prevents the disks from sticking together. Different lubes seem to work for different people. For me, nothing beats synthetic ATF. My advice is try them all, see what works for you.
Oversimplified to be sure, but that's the gist of it.
Tourer
Joined: Dec 2007
Posts: 386
Likes: 4
From: ND
I've always thought it was the compensator.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski