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[CVO103]

How much can i mill the heads?
How much will the compression increase?
Is there any piston for this head?

Regards

J-O

[Talon]

It depends on a lot of thing, are you changing pistons, cam's, and what head gasket your going to use?

[DCFIREMANN]

OK J-O That was the pic I was looking for. Those are CVO heads.

You can mill up to 90 thou off the heads. I would not reccomend going that far. 30 thou will jump the compression up to about 10.5 to 1 if you have the SE after market pistions. You may want to use a 030 cometic head gasket as well. That will depend on what cams you are using. You don't want to much cranking pressure

Be Safe

THE DAWG

[CVO103]

I have the kit 29877-06 with pistons, cylinders and flywheel it's complete kit.
Wich aftermarket pistons?
I think it will be Andrews TW54 cams.

[johnsachs]

You can mill the heads to death,buttttttttttttt the major factor,in your case, is getting the 1 piece throttle body to fit.
As you mill,the distance between the cylinders decreases.
Be careful.
John

[Classic Beast]

Here is a chart that gives you an Idea of the compression ratio change when milling your heads, with a larger bore it has more effect.

Head Compression Ratio
Milling (T)               EV80                       Twin 88
.000 . . . . . . . . . . . 8.50 . . . . . . . . . . . . 9.00
.020 . . . . . . . . . . . 8.77 . . . . . . . . . . . . 9.33
.040 . . . . . . . . . . . 9.07 . . . . . . . . . . . . 9.69
.060 . . . . . . . . . . . 9.39 . . . . . . . . . . . . 10.09
.080 . . . . . . . . . . . 9.73 . . . . . . . . . . . . 10.52
.100 . . . . . . . . . . . 10.11 . . . . . . . . . . . 11.00

[Classic Beast]

On the pic of your heads it doesn't look like there is much of a quench area, just the chamfer around the bottom edge. If this chamfer matches the pistons then you will have to make sure it goes back in after milling or the pistons will hit. Also make sure you have at least .030" to allow for thermal growth. I have milled .050" on heads before and did notice the difference, beyond that and you might start running into clearance problems with the manifold, valves etc. The best way to increase compression though is with new pistons that are designed properly, 10.5 would probably be max for these heads and should be matched with the right cams to take advantage of them as if you don't increase the duration of the cam you could run into detonation problems as the stock cam timing is more suited to a lower compression.

[DCFIREMANN]

The 103 CVO motors come from the factory with a compression ratio of approx 8.7 to 1. If you do mill the heads on a daily street driver stay at about 20 to 30 thou. If you are looking to up the performance, you need to purchase a set of CVO aftermarket cams. Zippers Performance or Freedom Cycle make them. They have early closing events on the valve timing and raise the compression that way. They work very well. A lot of the members on this board have used them with much success.  While the heads are off you might as well clean up the ports and do a performance valve job as well as change the valve springs. Add a fueling pump and a Baisley spring with a good set of lifters and adjustable push rods and you will be good to go!!!!

Be Safe

THE DAWG 

[Classic Beast]

It looks like your kit is already at 9:1 with the matching but cast pistons. You could go with the 22483-04 Pistons to give you 10.5 / 1 these will be matched to your heads. I would go with the 258 cams Put in the Zippers thunder max ECM with the Oxygen sensors and the larger Zippers 54mm throttle body and you should be good to go. If you have the cash have your heads cleaned up match the ports and cc the combustion chambers this is free HP as long as you don't go too extreme.

29877-06
SCREAMIN’ EAGLE® STREET LEGAL
103 CUBIC INCH STAGE I KIT FOR EFI MODELS
Bring your ’03-’06 Twin Cam motorcycle up to a whopping
1690cc. This 50-state street legal kit combines all the
proven components of the Screamin’ Eagle 103 cubic inch
models – the 4-3/8" stroker flywheel assembly, 3-7/8" big
bore cast pistons, big bore cylinders, SE-253 camshafts,
cylinder heads, air cleaner assembly and cover insert and
catalyst mufflers when required. The highlighted Screamin’
Eagle 103 cylinder heads and cast piston combination
offers a 9:1 compression ratio for easy starting. The cylinder
heads also prominently feature the “Screamin’ Eagle
103” script. Kit includes all required gaskets

[DCFIREMANN]

Classic Beast that would be a good build but he is in Sweedeen. If he hhas any problems tuning the Thunder max he will be S%&T out of luck. I know he can download a map that will be close but that is beyond some people. Unless he wants to change the pistons he would be better off with Zippers Red Shift TC575 cams.


Be Safe

THE DAWG

[Classic Beast]

Just finished a build in june with this exact set up in a 2005 RK and does it run sweet, gives my 127 a run for its money. Since he's in Sweden even more reason to stay with All harley parts (258 cams). I found with the Zippers just an email to them with the details and they sent us a map that worked perfect first time.  So the red shift 575's work good with 9/1, 103 I haven't tried them? I will have to remember that for next time. Thanks for the feedback. 

[DCFIREMANN]

Just finished a build in june with this exact set up in a 2005 RK and does it run sweet, gives my 127 a run for its money. Since he's in Sweden even more reason to stay with All harley parts (258 cams). I found with the Zippers just an email to them with the details and they sent us a map that worked perfect first time.  So the red shift 575's work good with 9/1, 103 I haven't tried them? I will have to remember that for next time. Thanks for the feedback. 

Yes they wrok very well. Plus they have a map already set up for the build.

Be Safe

THE DAWG

[Fired00d]

Yes they wrok very well. Plus they have a map already set up for the build.

Be Safe

THE DAWG

Don't have the Thundermax, but do have the cams (575's) and they put a smile on my face every time I twist the throttle.

 
Ride Safe,
Fired00d
 

[CVO103]

You could go with the 22483-04 Pistons to give you 10.5. 

Can i use this piston with "Screamin' Eagle 103" heads?

If i can i don't have to mill the heads.

J-O

[Classic Beast]

If thats the kit you bought then you have the 103+ heads these pistons are designed for them but check with harley just to make sure. They look like the 103+ heads though.



SCREAMIN’ EAGLE PRO TWIN CAM STROKER
PISTONS FOR “103+” CYLINDER HEADS*
These 3-7/8" Big Bore forged pistons feature a dome
shape that is matched to the Screamin’ Eagle “103+”
Cylinder Heads to maximize horsepower output. When used
in combination with the Screamin’ Eagle 103+ Cylinder
heads, Screamin’ Eagle Stroker Flywheels or 2007 Twin
Cam models with stock 4-3/8" stroke flywheels, and Big
Bore Cylinders, the resulting compression ratio is 10.5:1.
Complete kit includes pistons, rings, wrist pins and clips.
All EFI models require ECM calibration* (priced separately).
For race application only.
103 C.I. Big Bore
Fits ’99-later Twin Cam models equipped with Screamin’
Eagle 103+ Cylinder Heads, Screamin’ Eagle Stroker
Flywheels or 2007 Twin Cam models with stock 4-3/8"
stroke flywheels, and Big Bore Cylinders.
22483-04 Standard Bore (pair). $279.95
22484-04 .005" o/s (pair). $279.95
22485-04 .010" o/s (pair). $279.95