Shovelhead A place to talk about Shovelheads.

PISTONS Drag Specialities

Thread Tools
 
Search this Thread
 
Old Mar 25, 2023 | 07:37 AM
  #1  
FXWG'80's Avatar
FXWG'80
Thread Starter
|
Cruiser
Liked
Loved
Community Favorite
Joined: Jan 2023
Posts: 101
Likes: 22
From: Italy
Default PISTONS Drag Specialities

I bought these Drag Specialties + 0.10 pistons, I can't find any arrows (which usually indicate the exhaust) on the face and the valve seats are the same size.

The only marks I find are those highlighted in the photos.

Who knows them and knows the correct assembly?








 
Reply
Old Mar 25, 2023 | 01:52 PM
  #2  
johnjzjz's Avatar
johnjzjz
Seasoned HDF Member
15 Year Member
Top Answer: 3
Joined: Nov 2006
Posts: 12,878
Likes: 5,449
From: la la land jerzey
Default

The cut out goes towards the connecting rod JCC type pistons

but we check them as they are off set wrist pin to the skirt front to the back so they stay in the bore correct at top and bottom dead center and not rock back and forth
 
Reply
Old Apr 4, 2023 | 01:40 AM
  #3  
FXWG'80's Avatar
FXWG'80
Thread Starter
|
Cruiser
Liked
Loved
Community Favorite
Joined: Jan 2023
Posts: 101
Likes: 22
From: Italy
Default

Originally Posted by johnjzjz
The cut out goes towards the connecting rod JCC type pistons

but we check them as they are off set wrist pin to the skirt front to the back so they stay in the bore correct at top and bottom dead center and not rock back and forth

I didn't understand correctly The cut out goes towards the connecting rod JCC type pistons

I measured from the piston pin bore, front and back and the measurement is the same. The hole is centered
I measured the valve faces on the piston head, and they are the same.
I've mounted the pistons in the cylinders in both directions and the top dead center always stays the same and the pistons don't wobble.

In the absence of arrows and other signs can I say that the pistons do not have a forced direc????


I wrote to JCC in Taiwan for instructions but got no response

The only doubt is this step.

 
Reply
Old Apr 4, 2023 | 05:07 AM
  #4  
Spanners39's Avatar
Spanners39
Seasoned HDF Member
15 Year Member
Photogenic
Liked
Loved
Joined: Dec 2010
Posts: 7,736
Likes: 1,524
From: Coromandel Peninsula New Zealand
Default

The thing you drew the ring around in the above pic, that is what John is referring to when he says " cut out".
 
Reply
Old Apr 4, 2023 | 05:45 AM
  #5  
jake24lt's Avatar
jake24lt
Stellar HDF Member
5 Year Member
Liked
Loved
Community Favorite
Joined: Jan 2017
Posts: 2,673
Likes: 2,073
From: Massachusetts
Default

The cut out in the skirt ( on both pistons) goes towards the "center of the engine" . In other words, both cutouts should face each other when installed.
 
Reply
Old Apr 4, 2023 | 09:57 AM
  #6  
Ken45's Avatar
Ken45
Road Master
Photogenic
Liked
Loved
Community Favorite
Joined: Oct 2022
Posts: 960
Likes: 668
From: USA
Default

I take it that there is only one cut like this on each piston ? I looked up piston wrist pin offset and found this. Do you have an original piston to compare to.I think you are doing to right thing by looking into this. I would be afraid to use those pistons until I knew.









 

Last edited by Ken45; Apr 4, 2023 at 10:18 AM.
Reply
Old Apr 4, 2023 | 10:14 AM
  #7  
FXWG'80's Avatar
FXWG'80
Thread Starter
|
Cruiser
Liked
Loved
Community Favorite
Joined: Jan 2023
Posts: 101
Likes: 22
From: Italy
Default

No there are two cuts on each piston, forward and backward

Two cuts, piston crown with equal valve faces, no arrows
The two pistons are the same

The only "sign" is that step...

 
Reply
Old Apr 4, 2023 | 10:22 AM
  #8  
Ken45's Avatar
Ken45
Road Master
Photogenic
Liked
Loved
Community Favorite
Joined: Oct 2022
Posts: 960
Likes: 668
From: USA
Default

Originally Posted by FXWG'80
No there are two cuts on each piston, forward and backward

Two cuts, piston crown with equal valve faces, no arrows
The two pistons are the same

The only "sign" is that step...
See above about what I saw about offset. I was doing an edit while you responded. Looks like to me that those pistons do not have it. I myself do not see that step.
 

Last edited by Ken45; Apr 4, 2023 at 10:24 AM.
Reply
HD Forum Stories

The Best of Harley-Davidson for Lifelong Riders

story-0

7 Times Harley-Davidson Chucked Tradition Out the Window

 Verdad Gallardo
story-1

7 Surprising Harley-Davidson Products that Are Not Motorcycles

 Verdad Gallardo
story-2

8 Best Harley-Davidson Motorcycles Ever

 Pouria Savadkouei
story-3

10 Worst Harley-Davidson Motorcycles Ever

 Pouria Savadkouei
story-4

Killer Custom's Jail Break Is The Breakout That Refused to Blend In

 Verdad Gallardo
story-5

Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?

 Verdad Gallardo
story-6

Harley-Davidson Reveals Super Cool Cafe Racer Concept

 Verdad Gallardo
story-7

Engraved Rebellion: Inside Bundnerbike's Glam Rock II

 Verdad Gallardo
story-8

10 Motorcycles You Should Never Buy

 Joe Kucinski
story-9

10 Things Harley-Davidson Needs to Fix in 2026

 Verdad Gallardo
Old Apr 4, 2023 | 10:24 AM
  #9  
FXWG'80's Avatar
FXWG'80
Thread Starter
|
Cruiser
Liked
Loved
Community Favorite
Joined: Jan 2023
Posts: 101
Likes: 22
From: Italy
Default







 
Reply
Old Apr 4, 2023 | 09:45 PM
  #10  
Ken45's Avatar
Ken45
Road Master
Photogenic
Liked
Loved
Community Favorite
Joined: Oct 2022
Posts: 960
Likes: 668
From: USA
Default

To me, that step would point to the side of the piston where the wrist pin goes in and I think that it is not an indicator of installation. It is just the way it is made. I reserve the right to be wrong. lol
 

Last edited by Ken45; Apr 4, 2023 at 10:03 PM.
Reply



All times are GMT -5. The time now is 08:31 AM.

story-0
7 Times Harley-Davidson Chucked Tradition Out the Window

Slideshow: Harley-Davidson built its reputation on nostalgia, but every so often, the company took a hard left turn into the future.

By Verdad Gallardo | 2026-05-20 11:18:19


VIEW MORE
story-1
7 Surprising Harley-Davidson Products that Are Not Motorcycles

Slideshow: The bar-and-shield logo shows up on far more than motorcycles, some of the company's most unexpected products have nothing to do with riding.

By Verdad Gallardo | 2026-04-29 16:50:35


VIEW MORE
story-2
8 Best Harley-Davidson Motorcycles Ever

Slideshow: Not every Harley gets it right, but these are the ones that genuinely earned their reputation.

By Pouria Savadkouei | 2026-04-15 14:23:21


VIEW MORE
story-3
10 Worst Harley-Davidson Motorcycles Ever

Slideshow: From the troubled AMF years to modern misfires, these bikes earned reputations for reliability issues, questionable engineering, or disappointing performance.

By Pouria Savadkouei | 2026-04-01 20:01:09


VIEW MORE
story-4
Killer Custom's Jail Break Is The Breakout That Refused to Blend In

Slideshow: Killer Custom's "Jail Breaker" build focuses more on stance and visual aggression than mechanical overhaul.

By Verdad Gallardo | 2026-03-18 19:20:32


VIEW MORE
story-5
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?

Slideshow: The Swiss custom shop has taken a Harley Softail and stretched it into something so long and low that it looks closer to a rolling sculpture than a conventional motorcycle.

By Verdad Gallardo | 2026-03-07 16:15:30


VIEW MORE
story-6
Harley-Davidson Reveals Super Cool Cafe Racer Concept

Slideshow: Harley-Davidson's new RMCR concept revives the café racer formula with modern hardware-and it may be exactly the reset the company needs.

By Verdad Gallardo | 2026-03-04 12:23:37


VIEW MORE
story-7
Engraved Rebellion: Inside Bundnerbike's Glam Rock II

Slideshow: A standard cruiser becomes an intricate metal canvas in the hands of a Swiss custom house known for pushing Harley-Davidson platforms far beyond their factory brief.

By Verdad Gallardo | 2026-02-24 18:19:44


VIEW MORE
story-8
10 Motorcycles You Should Never Buy

Slideshow: There is no shortage of great motorcycles to buy, but we would avoid these ten.

By Joe Kucinski | 2026-02-19 14:50:51


VIEW MORE
story-9
10 Things Harley-Davidson Needs to Fix in 2026

Slideshow: Harley-Davidson's challenges aren't abstract; they show up in dropping shipments, shrinking dealer traffic, and strategic decisions that aren't yet translating into growth.

By Verdad Gallardo | 2026-01-13 18:33:17


VIEW MORE