I finally got around to cc'ing the heads I'm going to use on my 117" big bore. They both cc'd between 88 & 89 cc's. The beaker I'm using is only graduated each cc, so fractions of a cc are best guess.
I took the dimensions of the combustion chamber to one of the draftsmen at work, the cad program figured the area at 11.08 sq.in. So what I am going to do is have the heads decked .012" which is 2.18 cc volume, this will bring the combustion chambers volume in at 86-87 cc. Putting all the info into Big Boyz calculator, this should give me a compression ratio of 11.03-11.13:1. Of course that is if the cylinder deck height is 0.000".
A hint about using the Big Boyz calculator, you won't get an accurate calculation if you don't put in the piston diameter and the top ring land distance. On the 117" it was .07 point of compression increase by not entering those figures.
What compression pistons are you using with the head work to arrive at 11.03-11.13:1 compression?
I am using the CP Carrillo BHM8117-FT. They're rated at 10.75:1 compression, but that is with the stock .045" gasket. With the .030" head gasket it comes out to 11:1 +- depending on the chamber size. I had the heads milled today, took .012" off and I just cc'd them at 86 cc's each, so it came out perfect.
Originally Posted by 19special
What year bike? Are going to a 117 or 117 to a 128? What cam are you using? Heck how about sharing everything about your plan?
Like Steve said, it is my 2017 RGS 107 going to 117". I've been working this direction since before all the 124" kits were available. I think it will make enough power to satisfy me.
So the plan is 117" 11.1:1 compression, stock heads, 64mm throttle body with the SE CNC'd manifold, Fullsac 2-1-2 header, stock muffler cans with 2" Fullsac cores, and the TTS 175 cam. With the heads cc'ing at 86 cc's the piston to cylinder deck height could be .005 and I would still be above 11:1 compression.
Originally Posted by Steve Cole
He has a 2017 Touring 107 bike. This was the bike we used for the M8 107 camshaft testing we did back a year or so ago with him.
I am using the CP Carrillo BHM8117-FT. They're rated at 10.75:1 compression, but that is with the stock .045" gasket. With the .030" head gasket it comes out to 11:1 +- depending on the chamber size. I had the heads milled today, took .012" off and I just cc'd them at 86 cc's each, so it came out perfect.
Like Steve said, it is my 2017 RGS 107 going to 117". I've been working this direction since before all the 124" kits were available. I think it will make enough power to satisfy me.
So the plan is 117" 11.1:1 compression, stock heads, 64mm throttle body with the SE CNC'd manifold, Fullsac 2-1-2 header, stock muffler cans with 2" Fullsac cores, and the TTS 175 cam. With the heads cc'ing at 86 cc's the piston to cylinder deck height could be .005 and I would still be above 11:1 compression.
Sounds like a great set up! It'll definitely put some extra rumble in your seat. I still need to change my exhaust to a 2-1 to get back the low-end torque that I've left on the table. It hurts my throttle response a bit down low. In time. Congrats on your build.
I received the throttle body and manifold from Surdyke the other day and just opened up this morning. I'll have to give the MOCO credit on this one, the manifold is truly a stunning piece.
What is really sort of weird is the CnC'd manifold and throttle body have to be ordered as separate pieces, but as such they are less expensive than the complete SE throttle body / manifold combination.
SCREAMIN' EAGLE EXTREME FLOW 64MM INTAKE MANIFOLD
Optimize performance from your Stage IV equiped Milwaukee-Eight powertrain by bolting on this Extreme-Flow 64mm Intake Manifold. The Cast aluminum body and ported intake runners provide smooth, undisturbed air intake you need for maximum power output. 2 to 4 HP increase over standard 64mm manifold.
#27300185 $229.95 (MANIFOLD ONLY)
SCREAMIN' EAGLE HIGH FLOW 64MM THROTTLE BODY
This Screamin' Eagle 64mm Throttle body will pass significantly more air and fuel mixture into the engine. Designed to be used with 64mm Screamin' Eagle intake manifolds, part number 27300145 or the Extreme Flow part number 27300185
Fits 17-later Milwaukee Eight Engines.
#27300147 $279.95 (THROTTLE BODY ONLY)
I'm sure somebody was going to ask me for the part numbers, so here you go.
12-23-2019 | 08:31 AM
Deck the Heads
