"Jack's" Kickass D-Shaped Intake Ports! Alive and running

[Jack]

Yamaha Chop.... has much HP as a 707cc will endure with Wiseco CR 500 long rods at the crank big end, Ross 78mm 10.5 pistons at the small end, with a 256 XSI cam dictating the valve action timing events,along with biggest mounted carbs possible along an exhaust system that actually pulls for scavenging and just run the pissing snot out it

 

[Jack]

I've been thinking about this porting job for about a week now, or since I saw the original post, and I found a question.

How do you transition from the round carburetor exit to the D shaped intake port? In the pictures there doesn't seem to be a smooth transition, which would introduce turbulence and hurt your intake airflow.

And "Good Luck" to you! You need to machine or form the "D" near the end of a new manifold or almost the entire length of the manifold if you choose to do so,just radius the "O" in about 1/2 into the "D"

 

[Yamaha_chop]

Yamaha Chop.... has much HP as a 707cc will endure with Wiseco CR 500 long rods at the crank big end, Ross 78mm 10.5 pistons at the small end, with a 256 XSI cam dictating the valve action timing events,along with biggest mounted carbs possible along an exhaust system that actually pulls for scavenging and just run the pissing snot out it

So that's about 87grins worth?

Keep on keepin on, love seeing something different!

 

[Jack]

Mr. Craig Weeks,
Hugh of HughsHandBuilt is a friend of mine ,as I am to him, who both share a common desire in making the XS 650 go faster and in doing so we've agreed not to disclose each others little tricks that we've picked up while wrenching on the XS650 and this would include MY VERSION OF THE D-PORTS being applied to the XS head. I went to Hugh to pass along some of my knowledge that I've gain over the past few years porting the XS head as I'm getting older and it's starting to show and that it remain confidential till that time ,you just can't take it with you.

At the present time Hugh and I are having fun with this ported head,it's the real deal and who's attentions for the moment is to share the D concept with our friends and when or if I decide in marketing this head to the racing field will be a partnership amongst two FRIENDS.

 

[650performance]

OK.
Craig