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[hdrider53]

I just ordered a SE Pro Stage 2 kit plus a set of SE MCR heads for my 2007 RG.
Stage 2 is basically 103 BB with flat top pistons and a SE255 cam.
According to the charts in the SE catalogue I will have 10:51 compression ratio with this setup.
That does not take into consideration of different cams however so I dont know how the SE255 cams
would effect the C/R if any.

My question is should I put different head gaskets on or use stock?
I heard somewhere about using cometic gaskets that are bit thinner to raise the compression.
Being mine is probably already going to be in the 10+ range would I want to do this or just keep the thicker
stock gaskets? I'm adding manual compression releases in the build. If I did go with the thinner cometic gaskets
what sort performance improvements would I achieve if any?

I will be running the D&D Fat Cats any guess as to what my HP and TQ numbers will be?
Also looking for a PC3 USB map if anyone is running something similar. I'm thinking of buying a
Thundermax auto tune but if I can get a map for the PC3 it would good.

[Tom149]

hdrider53,

Here is a calculator that you can use to get some ideas. You can punch in all the info, including engine size, gasket thickness, cylinder head volume (cc value), piston dome value, cams, and altitude to get your estimated static compression, corrected compression, and CCP. These are close estimates! I wouldn't go too high with your compression at our 5280 altitude and with unreliable gas (pinging)!

When I ran your numbers looks like if you go with 0.030 head gaskets you will be at about 11.12:1 static and 10.78:1 corrected with a CCP of 198 at our altitude and those MCR heads. I would stay with the 0.040 gaskets with those 76cc heads at our altitude which will yield about 10.89:1 static and 10.55:1 corrected compression with a CCP of about 192.7 with 0.00 deck height. You should get some good numbers with the build you are contemplating especially with the 2 into 1 fatcats. Probably 100 -110 PWR and 110 - 120 TRQ with a good tune with the torque coming in over 100 by 2000 rpm IMHO.

One thing to consider is that those SE255 cams drop off torque early in the rpm range, you might want to consider Andrews 54 or 48 cams which will still get you early torque and hold that torque longer. I would call Andrews tech dept., describe your build, and see which they would recommend. (just a suggestion)

http://www.bigboyzcycles.com/TwinCamComp.htm

Tom

[hdrider53]

Thats the info I was looking for, thanks Tom.
That calculator is great. I was thinking at this altitude and the crappy gas
out there I shouldn't get the C/R too high especially on a touring bike.
I will stick with stock thickness on the head gasket.

How many other CVO readers in the Denver area.
We should hook up for a ride this summer.

[Tom149]

Thats the info I was looking for, thanks Tom.
That calculator is great. I was thinking at this altitude and the crappy gas
out there I shouldn't get the C/R too high especially on a touring bike.
I will stick with stock thickness on the head gasket.

How many other CVO readers in the Denver area.
We should hook up for a ride this summer.

My pleasure, glad I could be of some help .... 

Tom

[HILLSIDECYCLE.COM]

As Tom said the 255's will run out of steam rather quickly.
A Wood TW-408-44 may be something to consider as well??
Scott

[HD Street Performance]

Hope that bike is never riden at sea level with that build.

[hdrider53]

I take a trip to the west coast every year.
What kind of problems will I have at sea level?

[Fullsac Performance]

I take a trip to the west coast every year.
What kind of problems will I have at sea level?

Don was politely trying to say its going to ping its guts out. I have to agree. You should really pass on the 255.
A cam with a closing in the 40-42 or later deg range would be a much better match with the high compression your considering.
My fav is the Andrews 54. There are many other suitable choices for your build as well.

JMHO.

Steve

[HD Street Performance]

Steve 

Problem is it will be about 10.77/1 and even with a .030 HG and even the 54 or Woods TW408-44 it would be a pinger.

Most I have seen run about 79cc head chambers on the late heads

Consider an Andrews 67 and all will be happy and quiet

With porting this combo has the potential to make 120 square with a respectable torque curve assuming the pipe is right, I have done it.

[Fullsac Performance]

Steve 

Problem is it will be about 10.77/1 and even with a .030 HG and even the 54 or Woods TW408-44 it would be a pinger.

Most I have seen run about 79cc head chambers on the late heads

Consider an Andrews 67 and all will be happy and quiet

With porting this combo has the potential to make 120 square with a respectable torque curve assuming the pipe is right, I have done it.

Your right.
I bet a good cylinder porter could add a few cc of chamber vollume to the heads for something that makes a little more sense
 for a Touring bike.

[HD Street Performance]

Yep very easy to do

[hdrider53]

Hummm now I'm confused. Looking at the calculator Tom posted if I run with the stock .045 head gaskets I should be right at 10:44/1 CR and 223 CCC at sea level. I'm not sure where the problem lies. I see a lot of bikes running 10:50/1 CR. Maybe the problem is the 223 CCC at sea level. But with Compression releases I would think that would be OK still.
I'm not opposed to buying a different cam even though the kit I bought already has the SE255 in it. I just want to make sure its for a good reason. I want more torque and HP and I ride in the middle RPM range most of the time. I don't go around hitting high rev numbers much but love to twist the throttle at around 2K and let it rip to say 5K and feel the power.

[HD Street Performance]

Maybe the problem is the 223 CCC

Bingo

Target 195 at sea level and the pinging will be gone with a good tune

[hdrider53]

Makes since 223 CCC is to much. While at my elevation I would be at about 196 ccc which is livable.
So my choice would be take the heads down and have the combustion chamber opened up some or get a different cam.
I changed the numbers on the calculator to a SE258 and they dropped dramatically.
Sounds like most you guys like the Andrews cams but I want a direct bolt in cam.
I'm doing the work myself and aim to keep it as simple as possible.

[Tom149]

Makes since 223 CCC is to much. While at my elevation I would be at about 196 ccc which is livable.
So my choice would be take the heads down and have the combustion chamber opened up some or get a different cam.
I changed the numbers on the calculator to a SE258 and they dropped dramatically.
Sounds like most you guys like the Andrews cams but I want a direct bolt in cam.
I'm doing the work myself and aim to keep it as simple as possible.

I agree with Don, Scott, and Steve < these guys really know their stuff

Andrews 54's are a direct bolt in cam with intake closing @ 42. That combined with opening those MCR heads to about 82cc with a 0.040 head gasket should get you an estimated 10.24:1 static compression and a 9.35:1 corrected compression with a CCP of 194.4 @ sea level and 165.3 @ 5280 ft.

Even if you never venture to lower altitudes the 255's with the 0.040 gaskets, and the 76cc heads has your CCP at about 192.7 @ 5280 ft; that CCP combined with a 10.89:1 static and 10.55:1 corrected compression could be a tuner's nightmare (pinging) at our altitude with our unreliable gas JMHO.

Tom