Milling heads for compression/2004 FLHTCUI
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Road Master
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From: Mnpls MN
Milling heads for compression/2004 FLHTCUI
I'm considering milling .050 off my heads and using a .030 thick gasket to bring my compression up to 10:1. Some of the builders that I've spoke with, told me this is a better way to go then using a domed piston. Will I have any issues with my throttle body fitting correctly after the fact?
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RE: Milling heads for compression/2004 FLHTCUI
You need to know what your chambers cc at before you know how much to mill to get to 10 to 1. I milled 38 thou to get to 9.5 to 1 and had no manifold fitment problems. Some have milled 50 thou with no problems others have had to shave the manifold to get it to fit.
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RE: Milling heads for compression/2004 FLHTCUI
not sure if throttle bodt will be problem.You will need new push rods youre moving head(also rocker).060 closer.As for comprression you did nt say factory pistons or not so I assume they are..040 will remove 14 ccs most cases(not all heads cc the same)the gaskets remove another 2 to 3 and if going .050 wheich should be 17 to 18 that would mean right at 20 cc s out which would be about perfect for 10:1.Personaly Id go to 95 inch kit or 103 if its 08 model.Then you start at 9.3 shave lil less add nice size cam for 10.5 compression and be ready to roll.
If you have intake problem anyone can remive little from both ends and at worst case you have to die grined side backe for clamps its not big deal
If you have intake problem anyone can remive little from both ends and at worst case you have to die grined side backe for clamps its not big deal
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Road Master
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From: Mnpls MN
RE: Milling heads for compression/2004 FLHTCUI
ORIGINAL: wydopn231
not sure if throttle bodt will be problem.You will need new push rods youre moving head(also rocker).060 closer.As for comprression you did nt say factory pistons or not so I assume they are..040 will remove 14 ccs most cases(not all heads cc the same)the gaskets remove another 2 to 3 and if going .050 wheich should be 17 to 18 that would mean right at 20 cc s out which would be about perfect for 10:1.Personaly Id go to 95 inch kit or 103 if its 08 model.Then you start at 9.3 shave lil less add nice size cam for 10.5 compression and be ready to roll.
If you have intake problem anyone can remive little from both ends and at worst case you have to die grined side backe for clamps its not big deal
not sure if throttle bodt will be problem.You will need new push rods youre moving head(also rocker).060 closer.As for comprression you did nt say factory pistons or not so I assume they are..040 will remove 14 ccs most cases(not all heads cc the same)the gaskets remove another 2 to 3 and if going .050 wheich should be 17 to 18 that would mean right at 20 cc s out which would be about perfect for 10:1.Personaly Id go to 95 inch kit or 103 if its 08 model.Then you start at 9.3 shave lil less add nice size cam for 10.5 compression and be ready to roll.
If you have intake problem anyone can remive little from both ends and at worst case you have to die grined side backe for clamps its not big deal
bored 88" out to95"
forged flat top KB pistons
Cometic .030 head gaskets
SE adjustable pushrods
Head Quarters HQ-0039-G cams
I would use the Head Quarters heads, but it's out of my budget. I'm using Dan Vance.
I can do all the grinding that I need to do myself. I'm a machinist. I thought it would be a serious issue.
Another question. Could I just mill the tops of my cylinders?
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RE: Milling heads for compression/2004 FLHTCUI
You could mill the cylinders to achieve zero deck height and use .030" HG, or mill to plus .010" and use .040" HG. You can't go much tighter or the piston will contact the head on the flat area surrounding the combustion chamber.If you mill your heads/cylinders take some time to measure and remove the correct amount from your manifold to achieve a good port match. you especially don't want the edge of the head port obstructing the flow from the manifold.
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RE: Milling heads for compression/2004 FLHTCUI
Check to make sure you are at 0 deck on pistons/cylinders. If you are in the hole then by all means shave some from the cylinders to get to 0 deck. Make sure you check piston to valve clearance and valve to valve clearance. KB's have a big valve pocket so valve to piston should not be an issue but better safe than sorry.
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RE: Milling heads for compression/2004 FLHTCUI
I just noticed on your engine description that you have 203 cams. Are you planning on changing them? The 203's don't like much compression, especially on a heavy bike like an FL, and usually require taking some timing out and richening the mixture to remove detonation. I hope you're changing cams also.
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Road Master
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From: Mnpls MN
RE: Milling heads for compression/2004 FLHTCUI
ORIGINAL: jrdinatale
I just noticed on your engine description that you have 203 cams. Are you planning on changing them? The 203's don't like much compression, especially on a heavy bike like an FL, and usually require taking some timing out and richening the mixture to remove detonation. I hope you're changing cams also.
I just noticed on your engine description that you have 203 cams. Are you planning on changing them? The 203's don't like much compression, especially on a heavy bike like an FL, and usually require taking some timing out and richening the mixture to remove detonation. I hope you're changing cams also.
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Road Master
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RE: Milling heads for compression/2004 FLHTCUI
'Shaving' the TB spigots isn't a big deal. Maybe this'll help:
http://www.*****************/forums/tw...ottlebody.html
AAhh, the link won't work. Nevermind.
VicW.
http://www.*****************/forums/tw...ottlebody.html
AAhh, the link won't work. Nevermind.
VicW.
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RE: Milling heads for compression/2004 FLHTCUI
all milling the heads is going to do is make the given fuel charge take place in a smaller
chamber since the head shape is radiused. why are you using a .03 thick gasket /
shy not take .02 off and a regular size gasket. whaqt about turning the bottom of the
cylinders in effect raising the piston level and consequently reducing the squish area
just remember its easy to take it off but hard to material back on if your not careful your
going to waste your head/cylinder
chamber since the head shape is radiused. why are you using a .03 thick gasket /
shy not take .02 off and a regular size gasket. whaqt about turning the bottom of the
cylinders in effect raising the piston level and consequently reducing the squish area
just remember its easy to take it off but hard to material back on if your not careful your
going to waste your head/cylinder