103" with High Compression
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Road Warrior
Joined: Mar 2008
Posts: 1,783
Likes: 10
From: Oh
103" with High Compression
How many out there running at least 10.5:1 compression with a 103" big bore? Any issues? Would you have done something different? I know a lot has to do with your cams and I am sure many have different cams. But, I really want to know who is running the high compression motors and also tour with them.
Seasoned HDF Member
Joined: Mar 2008
Posts: 9,384
Likes: 1,776
From: Central Texas
I am running 10.5:1 compression in a 103 build.
I don't have compression releases, and I did change out
my starter to the Harley heavy duty starter, just because
I wanted to. The only problem that I have is, the cost of
new rear tires
I don't have compression releases, and I did change out
my starter to the Harley heavy duty starter, just because
I wanted to. The only problem that I have is, the cost of
new rear tires
Road Master
Joined: Nov 2007
Posts: 771
Likes: 3
From: St. Bonifacius, MN
I also have 10.5 to 1 compression and have compression releases, but have not had to use them. As you stated cams make the difference. I also changed to a 1.4 kw starter after two months of running the stock one. The stock one started the bike everytime, but wanted to go chrome so bumped it to the 1.4 at the same time. Put 20,000 miles on it last year from 114 to 26 degrees with an average of 41 mpg with no issues.
Outstanding HDF Member
Joined: Jul 2009
Posts: 2,313
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i just had my big bore kit with 10.5.1 compression my pipes are a lot louder. do have compression releases which iam glad i did. once the bike gets warm it turns over hard cuz a few times i forgot to push down compression releases. other than that iam satisfied with the performance just a little suprised at the dyno numbers.it doesnt add up the numbers to the performance the bike pulls pretty hard but the numbers are a little low.hp=91.10 tq=101.70 any way good luck ride safe.
Rick
Rick
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Road Warrior
Joined: Mar 2008
Posts: 1,783
Likes: 10
From: Oh
i just had my big bore kit with 10.5.1 compression my pipes are a lot louder. do have compression releases which iam glad i did. once the bike gets warm it turns over hard cuz a few times i forgot to push down compression releases. other than that iam satisfied with the performance just a little suprised at the dyno numbers.it doesnt add up the numbers to the performance the bike pulls pretty hard but the numbers are a little low.hp=91.10 tq=101.70 any way good luck ride safe.
Rick
Rick
Seasoned HDF Member
Joined: Dec 2005
Posts: 5,462
Likes: 619
My Headquarters 103 is at 10.5:1 with 205ccp. The HQ575 cams have a pretty early intake close. No issues now. I was getting a little pinging until I added the Jagg oil cooler. Now all is good.
The more compression you run, the better the tune needs to be.
Zach
The more compression you run, the better the tune needs to be.
Zach
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Seasoned HDF Member
Joined: Jun 2006
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From: King George, VA
I would do it again with the HC setup. Starting in the winter is very rough on the starter so the CRs are a must. Love the initial startup though with almost an explosion as it wakes up.
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Road Warrior
Joined: Nov 2007
Posts: 1,589
Likes: 3
I am running 9.8:1 on the ultra with manual compression releases just in case. I didn't want anything higher in compression for when I travel and have to run junk gas.
On my dyna it is 10.8:1 with manual compression releases and I have to use them to make the bike crank.
On my dyna it is 10.8:1 with manual compression releases and I have to use them to make the bike crank.