Changing Intake ports to a D shape for better flow.

[Jack]

When you start factoring in the high lifts from megacycle and factoring in the horrible blockage and turns in the exhaust port and address those areas,then the head become a power producing factor but yes it's the overall package.
As far as condemning products in the past, you'll have to refresh my memory cause I haven't been on this forum probably for close to two years and if you're referring to Mikes XS then yes alot of their products are garbage with absolutely no quality control.
I don't think I ever referred to the D on the head I'm working on as a record breaker and would be foolish implying that. What the D port did do on welded up combustion chamber was recover what CFM and Velocity I lost from shrouding the valves and this port shape was a blessing and a key factor which I have no
doubt would deliver great manageable power down low up to reline on an open chamber in street forum. I'm really contemplating installing 2mm over size intake just to see what this port is really capable of pulling.
I also apologize for mis judging you!

 

[650trader]

Accepted . All I was saying is these Idea's would be usefull if we could see some end numbers.
No one except Jerry Heiden has ever provided proof. Bill Boggs once took a Kawasaki W 650 and
said that it would have been impossible to get the bike to run correctly and make any power if he had not
paid for Dyno time. My reference goes back to the Garage site and I believe anything on the old Mikes site
was from Heidens Dyno work. Heiden Dyno tests every product and every tune-up. Heiden was a Yamaha
factory race mechanic for years and really knows his stuff, too bad he is semi retired now.

 

[Jack]

Went back to the "Garage" for close to three hours where I spent most of the time in modified section and couldn't find one reference regarding
Heiden dyno #'s being inflated. Don't know him and I'll leave it at that.
Do you by any chance have any experience with 3M epoxy#1838? Craig Weeks mentions it in is book but I have searched high and low
at "Speed Talk" and the web, they're either using Splash Zone, Devcon,JB Weld and a few others but no one mentions the use of 1838.

 

[TwoManyXS1Bs]

Awhile back, I was researching bonding agents for aluminum, and found many disappointing reports.

There's some good aluminum bonding agents in the aircraft industry, but I only used one of those (very expensive, fuel resistant, but not rated for heat/oil environment), and forgot what it was. It was the replacement for the failed 'purple passion' bonding agent used in the construction of early Jim Bede designed AA-1's and AA-5's.

With the recent advent of the new semi-aluminum Ford F-150, there's been a lot of buzz about the new bonding agents used for the tricky aluminum to steel joints. Could be something to look into...

 

[Jack]

Awhile back, I was researching bonding agents for aluminum, and found many disappointing reports.

There's some good aluminum bonding agents in the aircraft industry, but I only used one of those (very expensive, fuel resistant, but not rated for heat/oil environment), and forgot what it was. It was the replacement for the failed 'purple passion' bonding agent used in the construction of early Jim Bede designed AA-1's and AA-5's.

With the recent advent of the new semi-aluminum Ford F-150, there's been a lot of buzz about the new bonding agents used for the tricky aluminum to steel joints. Could be something to look into...

Thanks 2M, I'll look into it. JB works really well with aluminum, preparation and anchoring in place is the key, was curious what other epoxies others might have tried.When I began working the bugs out of this port, I applied alot of JB weld in my R/90S intake" a risky and expensive move" but was necessary for testing and it remained adhered for 4 years and some 25,000 plus miles but removing it was not easy, tried chiseling it out and failed, finally had to grind it out, so that's encouraging.

 

[TwoManyXS1Bs]

You're right about the anchoring and prep. Caution with carbon-tet, it can chlorate/attack aluminum. The JB to aluminum bond failures I've experienced were mostly on sheet aluminum. Probably because of the flexibility of the sheet.

What's nice about the epoxies is you can make a flexible mold to form a shape. Done that before on jobs that I don't want to post-grind and clean. It will easily release from certain plastics, saran wrap, sandwich bags, scotch tape.

BTW, from an aerodynamics viewpoint, I can visualize serious improvements from the D-port around the short turn, as long as the curvature is large radius, avoiding the "separation/stall" scenario. I wonder if golf ball dimpling has been tried there...

 

[Jack]

What's to be gained by it? Better to use the time delivering newspapers.

For a broader street power band( delivering papers) or racing , smaller higher velocity ports create more inertia packing(filling) the cylinders tighter over a wider RPM range say over a larger slow moving port of the same CFM. They're just a more efficient port overall.

 

[Jack]

You're right about the anchoring and prep. Caution with carbon-tet, it can chlorate/attack aluminum. The JB to aluminum bond failures I've experienced were mostly on sheet aluminum. Probably because of the flexibility of the sheet.

What's nice about the epoxies is you can make a flexible mold to form a shape. Done that before on jobs that I don't want to post-grind and clean. It will easily release from certain plastics, saran wrap, sandwich bags, scotch tape.

BTW, from an aerodynamics viewpoint, I can visualize serious improvements from the D-port around the short turn, as long as the curvature is large radius, avoiding the "separation/stall" scenario. I wonder if golf ball dimpling has been tried there...

Finally someone who gets it.
I use 36 or 40 grit cartridges for barrier finish.

 

[Jack]

Ok lets try this again, need to know if this images are clear enough for those who might attempt this porting.The first three are in first stage of working floor,last two are second stage of floor mod. Can you tell where I worked the floor in the last two.

 

[Jack]

image 2

 

[Jack]

image 3

 

[Jack]

image 4

 

[Jack]

image 5

 

[TwoManyXS1Bs]

... Can you tell where I worked the floor in the last two...

Looks like you've come in from the combustion chamber side to work the short turn?

 

[Jack]

Looks like you've come in from the combustion chamber side to work the short turn?

You were close, this just shows how port images can be deceiving in what areas where modified. These ports were opened up on a mill with incorrect floor
angle resulting in burring out more towards the spigot inlet area than evenly towards the short turn, the fix is easy but angle is important, I just have to add more JB to raise spigot inlet for correct dimension. When floor is completely raised, then you work from combustion chamber to radius short turn by hand.
I took another image shot and darkened it up to highlight that defected area. Now you can visually see the mill cut.

 

[TwoManyXS1Bs]

I always admired porting and flowbench work, did some back in the '70s, so my experiences with it are quite dated. Studied some of Jerry Branch's ports, read up on his work. Interesting story about his improvements to the 4-cyl Vega head. A GM contract could've really helped his business, but his improvements exceeded what GM wanted, cancelled.

I recalled studying the "Area Rule" in aerodynamics, where you want to have smooth transitions in cross-sectional area, and wondered if it should apply in port work.

 

[Jack]

Got a PM from a member overseas asking me to D port a head for him so that he might learn this and pass on to his freinds,etc, to be honest here
I don't care what he does with it cuz I'm flattered that someone 4000 plus miles wants to learn this. I need your input guys, pm or something, I need to think on this.

 

[Jack]

The member is from Germany up north and PM him telling him it would better if we correspond by email in his language if he'd like and my wife would translate emails since she's German. If he's not in a rush,the wife is planning a trip in May to visit her family and she could pick the head up to save him shipping cost over here,so we'll go from there. Thanks for the responses! Life is to short to hang onto knowledge that could be passed on to the younger XS650 enthusiast in keeping the XS alive and pushing it's performance another notch.

 

[TwoManyXS1Bs]

Something to consider, what Jerry Branch did, make casting plugs of the finished ports, then could mass replicate...

 

[Jack]

Something to consider, what Jerry Branch did, make casting plugs of the finished ports, then could mass replicate...

I have a port thats completed that I use for references in duplicating the D using inside dividers measuring in quarter increments.
On your question above regarding the "Area" I tried something similar to the first fuselage near the cross section of the S/T and loss flow. Port length might be a factor, I just didn't explore it further.