Ditto! Best kept secret in a bolt on cam. Really woke up a rather docile 103. Not a bad way to go for a budget minded performance upgrade.

 

Only some models of the CVO bikes have a Hemi style head. And I assure you these things will ping like crazy. I have spent seven years playing with the tuning on my bike one way or the other. Pinging was actually what got me into tuning this thing. I'm certainly not a drag racer with ET times to prove my theory. I am confident how my bike is timed is working well. Actually I'm wondering now if I should start carrying the max timing down from 3000 RPMs because as soon as I hit three grand my bike physically squats and goes. It feels like turbos have kicked in. I thought it was just right where the heads really started flowing but now I'm beginning to wonder if it's timing. Although I do recall pulling a lot of timing out of the lower RPMs because of knock events. The timing tables at least in my ECM only go to 3000 RPMs. That is where total timing starts, it's 3 grand to redline.

 

I'm relatively sure that the cvo heads are all hemi type chambers. They work well as long as you don't want much compression. The squish band on the bathtub style heads actually works better for eliminating detonation by causing turbulence in the chamber. The big "wide open" hemi chamber does little to mix up the air/fuel during compression . This is precisely why my upcoming build WILL NOT include my current cvo heads.

 

That very well could be. I only knew that at least some of them were. I was talking to the guy that ported my heads and asked if I should buy CVO heads down the road and he said "why the hell would you do that. Even with only my stage one porting these heads are better than any CVO heads ever will be." Maybe he was referring to the fact they are Hemi heads. I don't know. I do know the heads he built for me work as he advertised.

 

Will try to settle some of the confusion. Even the bathtub style head is a hemi head or if you prefer it is a semi hemi. The reason lot of folks don't like the CVO head is because it has ports and valves that are really too large for the smaller motors. The combustion chamber is 93CC and the 103 is 85CC. They do have a squish band on both heads. The original car hemi's had one also. If you will look at the car hemi piston it has a squish band about 1/4" wide all the way around it. That was one of the advantages to the design. Another advantage was to be able to get larger valves in the cylinder and get good flow around them due to one side not being next to the cylinder wall as in wedge head. The hemi head design is still one of the most efficient designs.

 

That may be a true statement for a 103 or 96 build. There sure are lots of builders building some worthless heads if that is a true statement. The ported 110 heads work great on larger engines. They will definitely out flow 103 ported heads. Sounds like your porter is using rectal data. I guess everyone is entitled to their opinion.

 

No he is definitely not. This guy is one of the best engine builders in a hundred mile radius of Pittsburgh and also a Harley drag bike racer (or at least used to be). He builds engines and does the machine work for a lot of the top racing teams around here. I was actually referred to him by the head mechanic at my dealership. I needed ACRs installed for my build as well as a helicoil installed in a stripped bolt hole and started talking to the head mechanic, he said we don't do that kind of work here we send the heads out and use this guy locally but you really want your heads done right go see this guy down south. It's a bit of a drive but well worth it. The guy delivered exactly what he said he would. One of the coolest machine shops I have stepped foot into. Dragsters and all kinds of race cars hanging from the ceiling. Also has a few drag bikes sitting on display in the back room. He also took a good hour of his time to explain properly tuning and building my motor to me. I did what he calls a stage one head build and had the heads shaved slightly. He also told me his stage one does more than the SE stage three heads. Next step is stage two where the heads are CC'd and bench flowed. Stage three is large valves and a hole bunch of other stuff. Honestly I just did the stage one because he said it would help with my touring bikes performance then he went off and discussed his stage two and stage three heads which I really did not pay all that much attention because their performance objectives were way beyond my goals for this build. Anyhow the man knows his stuff and he knows Harleys.

I am just a backyard mechanic and hotrodder. I fiddle around a lot through trial and error until I get things running the way I want them to run. My bike runs good, really good. It has exceeded all the objectives I set for this mild build. I use the knowledge and expertise of guys like the guy that built my heads to help me get to where I want to go. Most of the time it's just a matter of asking the right questions to someone that really knows what they are doing. That being said, I have built a lot of engines over the years and learned a few things along the way. To me these Harley motors are pretty simple things and respond really well to mild tweaks and breathing changes. They remind me of the old VW air cooled motors I used to build as a kid. They are not nearly as fussy as building up a big block v8 and the tolerances in general are a lot looser.

When I was researching timing yesterday on the twinkies I was really surprised at the wide range of timing used on these motors and various methods different guys used to get their timing set up. My conclusion was these motors are not particularly fussy about how they are timed within a range. I don't have proof but I have a sneaking suspicion that max power is achieved over a pretty wide timing range on these motors.

 

If he has some data like CFM, that would be helpful. Or a dyno comparison.

 

Very good results with SE 255 on my touring bike that I use with my wife.

 

I just put an andrews 57h in my bike. I'm running 4 in rhinehart true duals and a heavy breather. My dyno numbers are in my sig. All I can say is you will have more then enough power. My bike runs like a bat out of hell. It will litterally take you out of the seat.
All your power is gonna be at 2000 to 4000 rpm. This is normally where your bike is running at speed. Andrews actually makes the se cams for harley. I would suggest an andrews myself .