Which is better
Thread Starter
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Dirt don't hurt
Joined: Jan 2011
Posts: 21,065
Likes: 4,561
From: Haslet Texas
Which is better
Scott at Hillside recommends milling down my heads to get the 9.5 - 1 compression which I am looking for.
I'm not sure I like that as it takes meat away from the heads I might need later incase they do warp.
So my question is this
Which is better milling the heads or getting higher compression pistons?
I'm not sure I like that as it takes meat away from the heads I might need later incase they do warp.
So my question is this
Which is better milling the heads or getting higher compression pistons?
Road Warrior
Joined: Apr 2007
Posts: 1,952
Likes: 15
From: Senoia, Ga., by way of Miami, Fl..
Scott at Hillside recommends milling down my heads to get the 9.5 - 1 compression which I am looking for.
I'm not sure I like that as it takes meat away from the heads I might need later incase they do warp.
So my question is this
Which is better milling the heads or getting higher compression pistons?
I'm not sure I like that as it takes meat away from the heads I might need later incase they do warp.
So my question is this
Which is better milling the heads or getting higher compression pistons?
Road Master
Joined: Sep 2013
Posts: 1,054
Likes: 441
From: Tejas
Scott at Hillside recommends milling down my heads to get the 9.5 - 1 compression which I am looking for.
I'm not sure I like that as it takes meat away from the heads I might need later incase they do warp.
So my question is this
Which is better milling the heads or getting higher compression pistons?
I'm not sure I like that as it takes meat away from the heads I might need later incase they do warp.
So my question is this
Which is better milling the heads or getting higher compression pistons?
I've notched shovel pitons to pass each other on the down stroke using longer skirted pistons and milling the cylinder bottoms.
Griz
Seasoned HDF Member
Joined: Aug 2007
Posts: 21,718
Likes: 17,555
From: Driftless Area
I milled .050" off my heads about 90,000 miles ago. No negative issues.
A friend did his engine shortly after I did mine, the only difference was mine was milled, and his was HC pistons. The thing I noticed was that my bike always started quicker with less turns of the starter.
A friend did his engine shortly after I did mine, the only difference was mine was milled, and his was HC pistons. The thing I noticed was that my bike always started quicker with less turns of the starter.
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Road Warrior
Joined: Dec 2007
Posts: 1,286
Likes: 64
From: SoCal
THC,
Like the guy said, there is no going back.
Because of that I am inclined to use pistons to get the compression since you probably will be pulling the cylinders anyway. Didn't you say somewhere that your base gaskets are leaking?
Like the guy said, there is no going back.
Because of that I am inclined to use pistons to get the compression since you probably will be pulling the cylinders anyway. Didn't you say somewhere that your base gaskets are leaking?
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Elite HDF Member
Joined: Sep 2007
Posts: 4,468
Likes: 12
From: Bluffton, South Carolina
Most of our performance engines got the heads milled for two reasons. First and most obvious more compression. Secondly to balance the combustion chambers. Harley heads can and do vary from head to head more than we like to see. This can make for more vibrations than there should be. So in closing if you are going to have the heads CC'ed then go ahead.
John
John
Road Captain
Joined: Aug 2012
Posts: 625
Likes: 102
From: New Albany, Ms.
Personal Choice
I think it depends on the individual's preference. Some, like myself, don't like taking material from the heads for reasons stated. Can't put it back on if you ever want to go back to stock compression. On the other hand, some people will argue that using domed pistons interfere with flame propagation. I tend to go along the later, reason being I come from a background of riding panheads & shovelheads that use dome pistons & know that dual-plugs are a fix for the flame propagation issue. You can dual-plug evo heads, but that costs more money. I went with S&S replacement heads, that are 8.8:1 out of the box & installed with a .030 head gasket gave me a cr of 9.25:1. Not a upgrade for everyone, but worked for me, & I still have my stock heads ,stored away. If I had to choose between milling the heads or domed pistons, I would go with milling the heads, because it would be cheaper, ( unless you needed a re-bore) & I think the performance would be a little better. And I do know that bumping the compression up put a BIG smile on my face! And this is just my opinion.
hth
Ride Safe,
Harold
hth
Ride Safe,
Harold