Copperwing wants a single carb so... copper manifold

[joedrum]

nice thread ...perfect on how we do things here to help each other ... opcorn:

 

[Bug]

Thanks for the flange pic! I can't make much from the scrap copper plate after my work yesterday so I'm going to try the y's. If they don't work well, I'll make them from aluminum like yours.

I do love the helpful atmosphere here! Always suggestions on improving a project, rather than tearing it apart with "why would you try".

Weekend work!
The carb surprised me by showing up on Saturday instead of Wednesday. I used some of my aluminum plate to make spacers so I could mount the carb above the 4" cap, without the throttle and accelerator pump interfering.

Carburetor spacers

• Bug
• Jun 15, 2015

I cut the 4"pipe down to the cap and ground it smooth. The combined walls of the cap and pipe gave me about 1/4" thickness to solder to. The best way to fit the plate over the cap without extra holes was to use the outside edge down the center.

1st half plenum top

• Bug
• Jun 15, 2015

I'll have to watch extra close there to make sure the aluminum spacers seal.

I drilled and tapped holes for allthread studs in the 1/4" plate. The threads went down the inner side walls of the cap, maybe a little extra grip there...

Here is the stack up, plenty of room for the accelerator pump cam.

Plenty clearance for acc. Pump

• Bug
• Jun 15, 2015

And the full view:

1st Dryfit

• Bug
• Jun 15, 2015

2 questions - Does anyone know off the top of their heads what the thread is for the fuel filter that is supposed to screw in there? I want to simply put a hose barb fitting there.
And the brass tube coming out to the left of the fuel inlet seems to be open to the bowl, no place for a solenoid there. Is it supposed to be open to the atmosphere or should I connect it somewhere?

Thanks!

 

[dan filipi]

Fittings at the red arrows are 1/8" npt pipe thread.
At the blue arrow, that's a special thread. I unscrewed the solenoid and took out the plunger pin then screwed it back in place. With the plunger removed, the bowl will vent into the filtered side of the air filter. On this carb from Langdon there is a chrome ball plugging the hole above the solenoid. On another carb that hole had a hose fitting on it intended to vent to a charcoal canister. On that carb I filled the hole with epoxy. Your carb is a bit different than both of mine so you'll have to trace where those holes go to supply bowl gas as well as vent the float bowl.

And yes, no point in rippin a guy for trying or doing something different. Nobody wins with attitude like that.

 

[canuckxxxx]

Hate to spoil the mood but I think you should have fit and soldered all the runners, from the heads to the plenum before soldering the top on the plenum. You are going to want to clean up and trim the runners flush with the plenum wall on the inside.

But it is looking very good. The 1/4" wall thickness of the plenum will make the runners-to-plenum junctions very strong. :good:

Brian

 

[Bug]

Thanks Dan, I was able to pick up a fitting on my way home from work.

Carburetor fuel inlet bowl vent

• Bug
• Jun 15, 2015

I opened it up to trace the brass fitting here. It goes into the fuel bowl from above the gasket, behind the float hinge, then the open space vents back into the filtered air. I think I'll fill this and the other three vacuum ports around the fuel cut-off solenoid with epoxy. oh, and the choke vacuum port.

Ya, I have to agree with you canuckxxxx, I thought of it after I had drilled/ tapped the holes. When I soldered the second half of the top, I heated it enough to melt the solder on the first half. I'm sure when I solder in the runners, the top plates will come loose again.

I've noticed on several plenum designs (from a google search), the runners protrude into the plenum. Of course, these are usually velocity stacks into a tuned plenum for a specific power-band and engine, but I was wondering if the runners would need to be cut flush to the walls or if there could be some benefit to leaving them long.
I also plan to attach them a little higher in the plenum wall, so I could solder tubing around the bottom of the plenum for heat. I don't want to put any tubing under it as I want it to sit as low as possible.

 

[slabghost]

Leaving them long enough to reach into the plenum some can give added turbulence to the fuel charge which may minimize pooling from an over rich or cold fuel charge.

 

[canuckxxxx]

Well to be honest, the runners on my copper manifold are not flush with the inside wall of the plenum, but I always figured that might be impeding flow at high RPMs. But I don't know that for sure.

The reason I left them like is that, with my 2" end cap, it is only about 1/16" thick and I wanted a good fillet of solder on both sides for strength. Also, when you are soldering it, it is nice to be able to heat both sides.

But I figured with your 1/4" wall thickness you could improve on my setup. When I look inside the type IV plenum, it is shaped like a funnel to the opening to each runner which I think helps flow.

Having said all that though, your much larger plenum, using the 4" end cap, will be a big improvement over mine. And, once you cut the big hole for the carb. in the top, you will have access to the inside for cleaning.
Brian

 

[joedrum]

everything looks great to me ....yes runners cut flush on inside might flow better ...but at what cost ...1/4" copper is a big help there ....but for me id think longer runners will help get the manifold easier to fit head and seal better before soldering ....then it could be cut back some is what i see ....ive got a similar manifold going on out of exhaust pipe......i think 4" center is great too i also am using 5" exhaust and the whole weber fits on top of it .....nice work ....

 

[Bug]

Well, I got the holes drilled and runners cut to length. I stuffed paper towels into the intakes to prevent anything falling in there and tried to solder it all together on the bike. It was definitely one of my less amazing jobs... the copper flanges transfered the heat to the head a little too efficiently, and with all the runners to conduct the heat away, I couldn't quite get the plenum hot enough. It looked bad and it was bad...

But I was being impatient and slapped it together. I hooked up the fuel line and started pumping gas into the carb. I was listening for the pump to bog down when the needle seated, but I heard dripping instead. Looking down the throat, I saw the puddle of gas forming as fuel flowed from all of the ports.
I opened up the carb, checked the valve was working, then adjusted the float level. That fixed that problem! I mounted her back up and turned her over. She quickly fired up and mostly purred.
I really messed up here though... remember those paper towels I was using to protect the intakes? Well, I forgot 2 of them... bits and pieces of charred paper went flying out of the exhaust!

I got her to idle around 1k and went hunting vacuum leaks. There were plenty. I marked most of them and removed the manifold. With it off of the bike, I could get it hot enough to properly melt the solder at the flanges. While I had it off, I took the opportunity to polish it up. After untold years, it was quite a job getting it to shine and I still have plenty work to polish it up, but here she is!

Copper Manifold

• Bug
• Jun 22, 2015

 

[canuckxxxx]

Nice looking manifold. I like the heater tube wrapped around the bottom. You are close. How are you clamping the flanges down to the head? Do you have Orings in the flanges?

Brian

 

[dan filipi]

Good progress, now working out the bugs and tweaks, cool!

 

[slabghost]

Looks good! Should work nice.

 

[Bug]

I got the throttle rigged up. The high speed arm was interfering with the back of the alternator. I cut it off and used the pieces to make brackets. The top section with the adjuster was drilled out to mount the cable. The straight section of the arm was bent to allow the cable to pass, but catch the knob at the end of the cable.

Throttle closed

• Bug
• Jun 24, 2015

And full throttle:

Full throttle

• Bug
• Jun 24, 2015

I bolted it to the head with scrap pieces of the copper plate, washers and the stock bolts. I'm going to have to do them proper, that's my next project. I also need to fix my leaky seal to the top of the plenum.
I couldn't get a stable idle but I had to take it for a spin. It felt rather gutless at lower rpms (2k) and flatlined at about 5500. It would rev higher but just had no power.

Don't take this as a ride review, I'm still far from done. I took care of the bad solders I had, now I need to fix the other vacuum leaks. Then I can work on jetting. I also still have to hook up the plenum heater. Plenty to do...

 

[slabghost]

Great progress.

 

[Ansimp]

All your leaks suck! :hihihi:

 

[Bug]

Ansimp » Thu Jun 25, 2015 8:45 am[/url]":1146h0jp]
All your leaks suck! :hihihi:

:smilie_happy:

Ya, and the backfires blow!

 

[AApple]

:headscratch: Not sure I'm diggin the angle of the throttle cable there....the inner cable is gunna saw into the outer cable like that. If left like that for long, it could cause the throttle to hang open, or stick shut. or even break. Is there no way to get it to be more of a straight shot from the bracket to the throttle lever on the carb? :builder:


Other than that, I kinda like the whole copper intake deal....nice job on all of that! :good:

 

[dan filipi]

Youre throttle grip twist is going to be very short.
Might want to add an extension bracket to the carb an inch or so long. That will make grip twist about the same as stock and make accel more gradual.

 

[Bug]

I don't know if I was being creative or lazy, but I was trying to make it using only the pieces of the throttle lever I had cut off. I angled it out like that to be sure the cable didn't catch on the secondary linkage. It won't be hard to do it up right.

You're right about the throttle twist, it is short. So while I'm at it, I'll extend the lever action.

 

[joedrum]

when hooch had a thottle like even stock it was a monster to keep in control with the low end torque so huge ...i now have greater than stock pull as a safety feature