The spigot manifold needs a thicker flange which Chris's manifolds have and the transition area of the D port sides will flare inward to that point,then I'll drill and tap two points in the floor and aluminum braze the floor with a gradual ramp.
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Changing Intake ports to a D shape for better flow.
- Thread starter Jack
- Start date
Went out yesterday bought some Hobart aluminum brazing rods did some practicing and I'm good with modifying the spigots. Contemplated how I was going to address the dips in port walls to straighten them out reducing port resistance and since I bought a 110 mig inverter awhile back I'd give it a shot one more time welding the intake ports
Before the welds were always porous and looked non professional but not this time,they turned out great. What I've found over the years is the XS casting make up is less than desirable and can burn through very quickly when heated up,it's best to fine tune the wire speed and amperage welding the intake port cold.
Here's an image example welded cold and non porous 4043 mig aluminum. I just don't feel comfortable applying JB weld on the port walls without some type of anchorage risking it coming off getting lodged in the valves.
Before the welds were always porous and looked non professional but not this time,they turned out great. What I've found over the years is the XS casting make up is less than desirable and can burn through very quickly when heated up,it's best to fine tune the wire speed and amperage welding the intake port cold.
Here's an image example welded cold and non porous 4043 mig aluminum. I just don't feel comfortable applying JB weld on the port walls without some type of anchorage risking it coming off getting lodged in the valves.
Got one port welded up and it turned out real good better than expected but the other port the welder started birds nesting,although I was able to get the sides welded up. The other port is about 50% done and hope to finish it up this weekend ,will be using Minnwax wood putty on the finished port to form a mold of the floor for duplication, then I'll proceed with modifying the port floor's anchorage for the JB Weld. Hope to rap up modifying Chris's head by next week.
I've come up with a way for bowl porting for you all to follow if you choose to port your heads, it's crude but it's the best I can do and it's very effective for port equalization.
I've come up with a way for bowl porting for you all to follow if you choose to port your heads, it's crude but it's the best I can do and it's very effective for port equalization.
Mig aluminum wire .035 (4043) is very soft and will birds nest up depending how you hold the mig gun,pressure on drive rollers,type of drive roller andI can hardly wait for the result. Did you get a grip on your welding equipment? What was it?
type of hose liner. A spool gun would be a better choice preventing birds nesting but reaching in the ports with the right gun tip angle is vital cuz
of the ports tight quarters . I finished up all the porting a few minutes ago and I'm waiting for the wood filler to harden,then I'll check port floors
for width equalization. I'll be drilling the floor for anchorage, cutting drywall HD reinforcement mesh tape to floor dimensions, this will prevent the epoxy from cracking and breaking loose. I will enclose several feet of this mesh for you, you can't rip this stuff apart it's that tough.
I cut a head fin off, prepped it for JBWeld and applied four pieces of the mesh and set the oven temp to 275 for two hours,checked it after cool down with a magnifying glass and there were no visual signs of cracking.
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spungle
XS650 Enthusiast
Do you have a picture of the current state? Above all I am curious about the welding.
In this image looking at the arrows,there are two areas where the castings dips in where the cylinder block stud goes and then curves out towards the port bowl and short turn. Although there's little flow drag on the port walls and if left unchecked in modifying, there's still enough disruption in flow causing resistance at the short turn and bowl, you can hear this resistance when flow testing. You can minimize this dip some but it still exists and I just eliminate the dip completely by welding it up to straighten the walls out.
Image of wall welded up. It's a real challenge welding this area with a head being cold, you have very little vision with that big mig nozzle blocking your view, you weld a strip, cut it down to check penetration, adjust welder settings a few times, repeat first step and then you go for it.
Left outer wall turned out ok. Port wall vertical dimension was in check,so I quit cutting
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Left port inner wall, turned out perfect.
Right side port outer wall. Turned out ok
Right side port inner wall. Turned out ok. Welding is just a better option over JB Weld in this area, it can't come loose. I hope you'll be pleased with my efforts and workmanship.
Chris is using Shell#1 , all efforts to maximize flow will be at 400 lift, short turn will be worked with a small radius,then modified if needed when flow testing.
spungle
XS650 Enthusiast
If you do the mesh/jbweld and anchorage can you please show us in a few photos how you do it? That would be very helpfull
And could you draw an original port entrance on transparent foil and put it over the modified one? So we can visual see the difference.
And could you draw an original port entrance on transparent foil and put it over the modified one? So we can visual see the difference.
Chris,this is the best I can do to illustrate the differences of the D port vs round port. As you can see D porting substantially opens and widens the floor
allowing more flow over a wider area vs round and when the floor is raised you shorten the distance to the roof which affects the velocity of flow travel
along the long side of the roof to the back side of the bowl leading to the valve. This D port reduces port volume, increases port velocity and the best
part without any flow lost. The round image isn't quite to spec 34mm probably around 32mm.
Tomorrow I will show the method I'm using for the epoxy anchorage. The floor will be raised
0.125 or 3.14 mms
allowing more flow over a wider area vs round and when the floor is raised you shorten the distance to the roof which affects the velocity of flow travel
along the long side of the roof to the back side of the bowl leading to the valve. This D port reduces port volume, increases port velocity and the best
part without any flow lost. The round image isn't quite to spec 34mm probably around 32mm.
Tomorrow I will show the method I'm using for the epoxy anchorage. The floor will be raised
0.125 or 3.14 mms
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here's the fiber mesh I will be using to hold the epoxy together.
Got some bolts baking in the oven testing thermal expansion,will post images hopefully today and waiting on a call for flow arrangements.If you do the mesh/jbweld and anchorage can you please show us in a few photos how you do it? That would be very helpfull
spungle
XS650 Enthusiast
I'm sure the head will make the xs a rocket. btw the name of my bike is Blitz. A friend give this name to the Bike
I'm sure the head will make the xs a rocket. btw the name of my bike is Blitz. A friend give this name to the Bike
Any photos of your build Spungle? I’m very interested to see what this beast of a head is going into!
Daniel.
I'm jealous.
Yamaha's notorious casting flaws strikes again, I had to shift the middle anchorage point over on one port some thinking
I could drill and tape opposite side like I have in the past experimenting, not this time, there isn't enough casting beneath the floor where I want to drill & tap.
Gonna clean another head up,heat it to 225 to see if I can't get that area hot enough using map gas and braze it.
I could drill and tape opposite side like I have in the past experimenting, not this time, there isn't enough casting beneath the floor where I want to drill & tap.
Gonna clean another head up,heat it to 225 to see if I can't get that area hot enough using map gas and braze it.
