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[SPIDERMAN]

Sorry to start a thread which I know has been kicked around before, but I can't seem to find what it is I am looking for. Would someone please describe exactly what the heads on a CVO 103 are. Hemi or Bathtub ? CC size, Max allowable valve lift etc. Also, what can be done to modify them ? I tried to change my cams once and after much ado, my dealer came back and said without changing the heads, I would have to stay with the stock cams. Bascially I'd like a little more low and mid range. Top end is fine, I can collect all the tickets I need with what I've got now. I don't want to break the bank and have decided against a 113 because they need to bore the cases for the bigger jugs. Sooo cams it is and buy new heads or rework the ones I've got ?

Thanks
             Big Brian

[DCFIREMANN]

Spider they are Hemi chambers. Not sure on th size of the chambers but they are BIG!!!!!! Valve lift we now know at least .585 but don't know how much more.

Be Safe

THE DAWG

[jimp]

I looked at the 103, 103 plus and HTCC heads side by side yesterday, it looked like the 103 head had a much larger chamber.

The person that showed them to me was getting ready to clay up the 103's.

[BLM777]

About every perspective of the "cam's and head's" discussion can be found in http://flhrsei.org/cgi-bin/yabb/YaBB.cgi?num=1129941853/90#90  and  http://flhrsei.org/cgi-bin/yabb/YaBB.cgi?num=1136599283/0#0  both of which are in the Twin Cam section.

[SPIDERMAN]

BLM   Thanks, this gets me part of the way there, I now know for sure that the heads are hemispherical. Why is that ? The SE CNC heads are bathtub. I know that you can install a cam up to about a .630 lift  what I don't know is the cc size of the chambers. What my tech at San Diego H-D tells me is that the combustion chamber of the stock CVO 103 head will only accept so much gas and air and increasing beyond that point actually causes the engine to lose power. As such, and this guy does not make commission on parts. I need to go to a head set up to accept a larger lift cam. In the past I've had various stock heads re-worked by Dave Mackey and had great success. The problem is Dave usually sets me up with a complete top end. I'm trying to stay with the 103 cylinders. Also, I would like to go with the larger displacement EFI unit now out. As I said, looking for more bottom and mid range without sacrificing reliability and rideability. Went through this 9 years ago with a 95 RK. Took me awhile to find the right combination, but I ended up with a very strong motor that never left me stranded ( knock wood)

later
         Big Brian

[DREBBIN]

Sorry to start a thread which I know has been kicked around before, but I can't seem to find what it is I am looking for. Would someone please describe exactly what the heads on a CVO 103 are. Hemi or Bathtub ? CC size, Max allowable valve lift etc. Also, what can be done to modify them ? I tried to change my cams once and after much ado, my dealer came back and said without changing the heads, I would have to stay with the stock cams. Bascially I'd like a little more low and mid range. Top end is fine, I can collect all the tickets I need with what I've got now. I don't want to break the bank and have decided against a 113 because they need to bore the cases for the bigger jugs. Sooo cams it is and buy new heads or rework the ones I've got ?

Thanks
             Big Brian

IMHO, pls don't do anything to those heads, cams, pistons, etc. I'm a guy that has done all that - all thru a dealer -- and BOTH times it was a D I S A S T E R. These SE CVO engines are plenty tricked out for us, IMHO

[BLM777]

Drebbin....would be interested to learn more about your multiple "disasters" so that we all might become aware of the mistakes that were obviously made.  As you may be aware from some of the posts here, there are several items on the stock 103 that need replacing (upgrading) such as the chain drive cams with the infamous plastic tensioners that sooner or later produce serious engine damage.  Could it be the "dealer" who was not familiar or experienced enough with performance mods that caused the problem?  

[grc]

Sorry to start a thread which I know has been kicked around before, but I can't seem to find what it is I am looking for. Would someone please describe exactly what the heads on a CVO 103 are. Hemi or Bathtub ? CC size, Max allowable valve lift etc. Also, what can be done to modify them ? I tried to change my cams once and after much ado, my dealer came back and said without changing the heads, I would have to stay with the stock cams. Basically I'd like a little more low and mid range. Top end is fine, I can collect all the tickets I need with what I've got now. I don't want to break the bank and have decided against a 113 because they need to bore the cases for the bigger jugs. Sooo cams it is and buy new heads or rework the ones I've got ?

Thanks
             Big Brian

Brian,

The MoCo hasn't exactly been forthcoming with details about the SE103 heads, so hard information is difficult to find.  I have read here somewhere that the combustion chambers were 94cc, which is huge.  The efficiency is poor due to the hemi shape with no squish area to improve turbulence, and due to the off-center spark plug.  I understand that several folks will modify the stock heads for you by welding up the chambers and creating a squish band - Short Block Charlie is one source I've seen mentioned here before.  There is a thread in the Twin Cam section concerning performance packages being developed by Zippers for our 103's that you may want to check out.  Also, try a search for 103 heads, you should come up with several threads that discuss this.

Jerry

[SPIDERMAN]

Jerry  Thanks as you are talking exactly what my research to date has shown. That being that the heads need to be welded up, and reconfigured to create a squish zone (if not two) as well as ported by someone who seriously understands flowmetrics. My dealer also is dead against any mods to the stock heads. No one seems to know what the factory had in mind with these heads. I thought perhaps the intent was to be able to support a 113 cylinder mod and larger cams, but everything I've found out is that they don't work well with either. As you say, the MoCo is not forthcoming. The wierd thing is with 7 years production run on these motors there is not more in the aftermarket world about them. Total production of CVO 103's has got to be pushing 20,000 units by now. Of course that's a drop in the bucket compared to the millions of EVO and Twin Cam 88 motors out there.

[GC_Super]

I think the CVO heads should be renamed EPA heads.  That's probably why they are what they are. It's obvious HD knows how to make better power, evidenced by the other heads available, they just can't meet the EPA numbers and make good power at the same time.

[grc]

I think the CVO heads should be renamed EPA heads.

[GC_Super]

Jerry, I've given up trying to figure out what goes thru the minds at HD.  Obviously they do some great stuff and make the shareholders happy too, but the phrase " what were they thinking" come to mind a lot.  LOL   [smiley=xyxthumbs.gif]

[Unbalanced]

Brian,

The information your seeking is here and most of it has been summed up pretty nicely for you.

The Travel on the Springs is 690 and 700 respectively with leaving .060 for clearances you get 630 lift.   GRC is correct in the CC I had mine CC'd and they came up with 94 cc.

The issue really becomes there is no Squish in these Hemi Heads.   These heads do not flow with much velocity which makes making bigger power really really tough.   The only time i have seen over 110/110 is when they weld up the chambers to make them into bathtubs vs hemi shapped.
and use a stock throttle body with a 625 cam.

I am currently waiting on Zippers to finish their prototypes and then I will decide from there what the next generation for me will be.  Zippers, T-Man, John Sachs, R&R, SBC, Branch

Hope that helps bring the information into one thread for you.

-harry

[geezerglide]

GRC,

You mentioned SBC, I am one of the people who had headword done by Charlie, he posted apprx. Sept. 2004, on his reworking of the SE 103" Heads.

Engine was an 04 SE 103". Here in a nutshell is what he did with my heads.

Install a 2" Intake and a 1.580 exhaust valve, weld up the combustion chamber to a swirl design. Compression set to 10:1, a fin is welded in the intake port designed to alter the flow of air fuel into the combustion chamber.

With the reworked heads, S&S 585 Cams and S&S Reed Valve, HD SERT, rest of the Engine Stock . Rhinehart Dual Exhaust at that time engine dynod at 106 HP and 117 Lb. Ft. TQ. Added SE HD 6 Speed. Now have a set of Freedom Cycle Rhineharts, yet to dyno with these pipes. Looking for RB Racing Blackhole 2:1 down the road.

Have about 10,000 + miles since, bike runs great. Engine is in an 03 Road Glide.

geezerglide