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Cylinder head porting questions #69667 05/08/12 10:44 PM
Joined: Jun 2011 Posts: 21 tigard, oregon P photwenny OP Active BB Member
OP photwenny Active BB Member P Joined: Jun 2011 Posts: 21 tigard, oregon	I just got my cylinder head back from the machine shop. I had the 1.94/ 1.60 valve installed and the head drilled for the lumps. Now I need to blend the bowls and also it seemed like the lumps fit a lot tighter before the machine work. My questions are: How much can I take out of the intake runners to match the valve opening? How should I blend the edges of the combustion chamber? What should I do with the edge of the lump closest to the valve? I have attached photos, first try, hopefully they show up. Looking for opinions. Thanks.

Re: Cylinder head porting questions photwenny #69670 05/08/12 11:41 PM
Joined: Sep 2004 Posts: 5,839 Likes: 1 Ca M Mean buzzen half dozen A.K.A. Hank 1000 Post Club
Mean buzzen half dozen A.K.A. Hank 1000 Post Club M Joined: Sep 2004 Posts: 5,839 Likes: 1 Ca	You can blend in the throat area below the valve seats, but do not go too deep, you will hit into the water jackets. Just blend it in. There is great risk if you are not familar w/these heads. You want the area below the machined portion pulled back a bit & as the A/F goes through the throat area that area will be the tightest, like a venturi, then open up wider @ the valve angles. Not good @ explaining, but hope it makes sense, easier for me to show in person. On the short turn radius, just blend it into a nice radius, do not worry about the gaps. No sharp edges. I use a piece of emery/cloth sandpaper, tear into 1/2 to 3/4" strips, longer strips makes it easier to hold & work faster, feed one end into the exhaust port & the other end comes out of the combustion chamber, hold both ends of the sandpaper & work it back & forth. Gets the areas you cannot reach w/a conventional porting tool. Example of sandpaper to get. http://compare.ebay.com/like/230769942302?var=lv<yp=AllFixedPriceItemTypes&var=sbar You can lay back the chamber wall a bit on the intake side on the spark plug side to increase airflow. Only have a pic of my different cyl head though. Also, you will loose some compression. You can also knotch the tops of the cyl bores to help w/airflow. Edges on the combustion chambers? Just break the sharp edges w/a cartridge roll or a carbide cutter. How much compresssion are you going to run? MBHD 12 port SDS EFI

Re: Cylinder head porting questions Mean buzzen half dozen A.K.A. Hank #69673 05/09/12 02:30 AM
Joined: Jun 2011 Posts: 21 tigard, oregon P photwenny OP Active BB Member
OP photwenny Active BB Member P Joined: Jun 2011 Posts: 21 tigard, oregon	zero deck, 64cc chamber, should be about 10.5:1.

Re: Cylinder head porting questions photwenny #69686 05/09/12 06:33 PM
Joined: Jun 2011 Posts: 21 tigard, oregon P photwenny OP Active BB Member
OP photwenny Active BB Member P Joined: Jun 2011 Posts: 21 tigard, oregon	If anyone has some examples of porting that they have done any pics would be a great help.

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