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103" with High Compression

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Old 01-14-2010, 06:43 AM
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Default 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.
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Old 01-14-2010, 08:36 AM
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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
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Old 01-14-2010, 09:54 AM
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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.
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Old 01-14-2010, 09:56 AM
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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
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Old 01-14-2010, 11:02 AM
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Same here have 107 with compression releases but never use them. Have 10.5 compression. No problems.
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Old 01-14-2010, 11:23 AM
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Quote:
Originally Posted by streetgliderick View Post
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
Looks like you did the SE stg 3. Did you do anything to the heads? The numbers don't mean anything, too many variables, equip, tuner, etc. How about the clutch, any work done on that?
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Old 01-14-2010, 02:17 PM
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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
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Old 01-14-2010, 02:54 PM
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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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Old 01-14-2010, 02:56 PM
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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.
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Old 01-15-2010, 05:46 AM
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Thanks for the replies guys. I am torn between going with 10.5:1 CR or going lower. I will have manual CR's installed regardless.
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103, 259e, 2902, cam, cams, compression, comprestion, crane, eagle, harley, head, heads, high, motor, screamin, se259e, timing, worked

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