Wethead compression
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
I think the combustion chamber in the heads is smaller
since the head temps are more stable, compression can be bumped up
the change in the heads can leave the lower end of the motor unchanged and interchangeable with other year and models
mike
since the head temps are more stable, compression can be bumped up
the change in the heads can leave the lower end of the motor unchanged and interchangeable with other year and models
mike
Road Master
Joined: Jun 2014
Posts: 1,219
Likes: 63
From: westland Michigan
Just a guess at best but here goes. I would say the design of the wet head is different and in course makes a smaller combustion chamber due to the fact that they had to run "coolant channels" thru the heads. hense the smaller chamber higher compression. Everything else seems to be the same.
Batman.
Batman.
Trending Topics
Tourer
Joined: Jul 2013
Posts: 286
Likes: 23
From: Ma
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
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Harley doesn't publish HP numbers but they do torque. The wet head does have more torque due to the higher compression.
Road Warrior
Joined: Apr 2010
Posts: 1,648
Likes: 37
From: Monroe, Louisiana
I know where a set of wet and air 14 pull offs are. I will mic and see if can figure it out. All the wet would have to be is about .030" less deck height to get that and possibly even more.