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Old 01-28-2012, 05:34 PM
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Stiggy Stiggy is offline
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Default Twin Cam Heads: Buy '06 or Rebuild '00

2000 95" FLTRSEI

Hi there,

I swapped out my original heads with a clean set of take-offs 2 years ago at 67,000 miles. (The original rear exhaust valve stuck and tapped the piston, bending the valve. A cracked Y Pipe may have been the culprit.)

Now at 102,000 miles, I'm thinking of getting ready for the top end job, ( +.005 cast pistons, freshened heads w/ fresh rockers,) whenever the motor indicates it's time. (Currently still no significant oil consumption = Less than 8 oz in 5,000 miles.)

So I thought I'd send out the old heads for new valves, guides, springs and seals so I'd be ready for it, and then I started thinking some more....

2000 heads are the old casting, while '06 flow better and feature 'bee-hive' springs, (as I've learned here.) And everyone seems to be talking 'street porting' as the smart thing to do while you've got it apart. So maybe fresh pieces/parts on the old heads isn't the smart move now.

At 81,000 miles I installed Andrews 26G Gear Drive cams which according to Big Boyz Calculator currently gives me 171 Cold Cranking Pressure, 9.09:1 Static CR and 8.53:1 Corrected CR with my stock .0045" Head Gasket.

Andrews website says that they like 'all around riding' CCP at 160 and 'Street Performance' at 175-180 for the 26G. So I'm right in the middle at 171.

I have not one complaint with my excellent motor. I do not 'hammer' it ever. Just lots of touring miles and my daily commute. When I need to pass quickly, the bike responds quickly and confidently with more than enough power.

So what's the smart thing to do?

Street port on a bike that rarely sees 4,000 rpm?

Used '06 Heads just bolted on?

Or given my conservative 'just ride it' style, stick with my old heads with a fresh valve job?

Thanks for the input!
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2000 FLTRSEI Stage II 95" Big Bore with Andrews 26 Gear Drives, Patriot Defender 2 into 1 Exhaust and a Good Air Filter.

Last edited by Stiggy; 01-28-2012 at 05:39 PM.
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  #2  
Old 01-28-2012, 05:54 PM
Shredding rubber Shredding rubber is offline
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Everett Morash
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Rebuild what you have. Then you have a new set instead of a pair with unknown miles and wear.
If it ain't broken
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2008 street bob. S&S 106,t6-6 cams,ported and polished and decked heads,manual compression releases,jagg oil cooler,V&H propipe and Willie G accessories everywhere. It's never been this easy to pull a wheelie
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Old 01-28-2012, 06:28 PM
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I don't believe .005" OS pistons are available from H-D any longer; .010" OS only.

As for the heads, the end result of porting your heads or a set of later castings will be the same; the trade off is down time vs cost. You are looking at $500-$600 for a basic street port from BigBoyz or another porter which will include retaining or replacing as needed OEM valves, new guide seals, cc and balance chamber volume, deck for compression, a radiused seat valve job and mild porting mostly on the exhaust side. In your case, you could have your springs swapped out for beehives if you wanted to pay for the springs. BTW, BigBoyz would also bore your cylinder, fit the pistons and gap the rings if he was your porter; others will do the same. Down time will most likely be at least four weeks.

The advantage of using the later casting, or a set of early castings, is no down time; you ride while you wait for parts. If you went with later castings, I don't see the value of a "street port". Just have the heads gone over but insist on a full radiused seat valve job. Those castings will support 100TQ without porting; done all the time.

Heads will need to be decked about .030" for 82cc chambers and 9.6., with a .030" head gasket. You could bolt on the '06 heads but I would not bolt them on without having them disassembled and guide seals replaced at a minimum. So, you have paid for some of the labor for the vavle job; why not have it done. Most guys look at cams and porting but overlook the importance of a really good valve job and the increase in compression to support the increase in performance.
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Old 01-28-2012, 09:43 PM
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Downtime plans to be a weekend. The original heads are currently sitting on a shelf in the garage, and the cylinders I will pick up used and have bored to match my .010" over cast flattops as I get the heads reworked.

If I understand then, according to the calculator:

82cc with a .030" head gasket (at my 400 ft elevation,) gets me corrected 9.04 to 1 CR and 184 Cold Cranking Pressure. Use my castings with the "full radiused" valve job and beehive springs installed, while keeping my Andrews 26G cams.

That sound right?
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Old 01-28-2012, 10:51 PM
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Quote:
Originally Posted by Stiggy View Post
Downtime plans to be a weekend. The original heads are currently sitting on a shelf in the garage, and the cylinders I will pick up used and have bored to match my .010" over cast flattops as I get the heads reworked.

If I understand then, according to the calculator:

82cc with a .030" head gasket (at my 400 ft elevation,) gets me corrected 9.04 to 1 CR and 184 Cold Cranking Pressure. Use my castings with the "full radiused" valve job and beehive springs installed, while keeping my Andrews 26G cams.

That sound right?
Not quite. If you are using early castings, they need a street port ala BigBoyz or some other porter that offers basic velocity porting. Prices will vary, so you need to pay attention to the scope of the service. BigBoyz street port for $299 includes minor porting, bowl blending, retains OEM valves and springs and new guide seals, radiused multi angle valve job, measure and equalize chamber volume. Decking and drilling for compression releases are
extra. Pretty good deal but other porters offer similar packages.

You could get more aggressive with compression by decreasing chamber volume until
corrected hits 9.3 or cranking hits 190psi. Compression releases would be nice to have at 190psi. One other thing that will help those cams would benefit from would be a set of the 1.7 ratio rockers on the intakes, or both.
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Old 01-29-2012, 06:20 AM
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Quote:
Originally Posted by djl View Post

You could get more aggressive with compression by decreasing chamber volume until corrected hits 9.3 or cranking hits 190psi. Compression releases would be nice to have at 190psi. One other thing that will help those cams would benefit from would be a set of the 1.7 ratio rockers on the intakes, or both.

As I was planning on replacing the rockers anyway, the 1.7 ratio rockers are in budget and were not considered until you just mentioned it ...Thanks!

In that mid-range power is everything to me, and considering that I often travel way off the beaten path, I think that 184 CCP will be good for my use and still considerably better than what I'm running now.

Thanks djl for taking the time, answering my questions and clearing up the confusion
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Old 01-29-2012, 06:20 AM
 
 
 
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06, benefit, buy, cam, cost, decking, harley, head, heads, port, ported, rebuild, street, swap, tc, twin


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