the PVC manifold didn't go so well so now I'm making one from copper plumbing parts

Classic Goldwings

Help Support Classic Goldwings:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

chuck c

Well-known member
Supporting Member
Joined
May 25, 2013
Messages
833
Reaction score
1
Location
Souderton PA
I'll start this with some of the designs I've sketched out.
This one uses the stock intake horns. The shape is not right, the 36mm offset isn't there. From what I can tell now that I have the parts in my hands and can measure them, this will give me some problems. Like the PCV, the fittings are too long and have to be cut down to get the spacing right. The difference is when I solder them they will seal and stay that way, even if they are only overlapping by 1/8". Also the 1" to 1.25" reducers are made to slip over the OD of the pipe and are too big to get into the rubber of the intake horns. I'll need short pieces of tube to do that and the reducer will stay entirely outside the rubber.
copper manifold.JPG

These two with flanges mounted directly to the heads. I'd need to make flanges which is not something most people can do but it's so tempting. They eliminate the annoying 7* angle of the stock intakes and give me much more room. I'm thinking of sawing off a set of horns to get the flanges and filling the gap to the copper with high temp silicone. It would allow the needed "give" for heat expansion.
This uses 2 standard 45 fittings. The real one isn't very pretty, it's a brass casting, but this shows the geometry works with off-the-shelf parts. Smooth and straight flow, too.
copper 2.JPG

I like the simplicity of this one.
copper 3.JPG
 
hmmmmmm if the last is the easy one to do.... then do it ... there is 1" off set ...going across like that ... so you have to off set the middle piece off center so the square tees will work and go together good

dont like the first one at all ..... on the second one ...hmmm not sure on it either ...to bad a true x cant be done ... that the only way to get equal lengths ....
 
I'm liking the second one most of all.
The flows are better, no hard turns.

What I don't like is the idea of silicone holding to the flanges. Gas eats most silicones and I just don't know about it's holding power.
Metal flanges soldered to the pipe is what I would do.

Great drawings btw.
 
[url=https://classicgoldwings.com/forum/viewtopic.php?p=133756#p133756:16w9juls said:
dan filipi » Sat Oct 18, 2014 9:04 pm[/url]":16w9juls]
I'm liking the second one most of all.
The flows are better, no hard turns.

What I don't like is the idea of silicone holding to the flanges. Gas eats most silicones and I just don't know about it's holding power.
Metal flanges soldered to the pipe is what I would do.

Great drawings btw.

Yeah, I'd need to test or otherwise be sure the silicone or whatever I used was able to stand the heat and possible contact with fuel. If I solder flanges solid I'd need to add flexible joints somewhere otherwise the heat expansion difference will over-stress something. O! I just got an idea. I could solder a short stub maybe a half inch onto the solid flange, then use a short section of rubber hose to connect to the manifolds. That would be pretty solid but still allow some flex.
Thanks, I do it for a living so I should be good with them by now!
 
My runners are solid brazed to steel flanges I made though I do use the type 4 manifold and rubber boots to couple the runners to it so I have flex.
Just a thought, maybe build then cut each runner and put rubber hose or something similar at the cuts to allow some flex?
 
Here's one with the runners exactly the same length. The angles are odd but maybe it could be bent. Then the coping at that Y for a tight fit and the hole needs to be exactly the right size. This one would be considerable work.
copper 5.JPG
 
Of course if you can bend any way you like you can do this. It might be flexible enough to not need rubber splices. Those big bends would let it flex.
copper 6.JPG


How I spent my saturday night....
 
[url=https://classicgoldwings.com/forum/viewtopic.php?p=133768#p133768:2gl8zpse said:
chuck c » Sat Oct 18, 2014 7:31 pm[/url]":2gl8zpse]
Of course if you can bend any way you like you can do this. It might be flexible enough to not need rubber splices. Those big bends would let it flex.


How I spent my saturday night....
file.php
Gas pooling would be a major problem with that one.
 
hmmm chuck ...well to me i never use plans much ...or no longer than to get the idea what i am doing ...seems most of the time plans fall way short of right ....planning is good ...truth is this is a very small boxer motor ...biggest discount is the not the 90 degree turm at the head ..but the 180degrre turn head included to the valve ... so past that you dont really want any more curves bends and such ....the type4 is a compromise too as it runner outlets face nothing where they go to the head on a oldwing ...on the plus side you couldnt have a better arrangement where the runners come together at the carb with no crowding ....and with a trasition piece 2 to 1 a vw carb could used and you would get the most from it ....or like i did plated the type 4 with plywood spacer and went 1 to 2 transition piece to use a dft 2 barrel carb ..this centers the gas charge equally for the perfectly space runners in the type4 ...i call this really something not to overlook ...its my opinion that short of the outlet runners not point to where they go ..this is best set up ...there is no way a pipe manifold can match the flow of this set up ....having the perfect volume ..not to big and not to small where the runners come together is the thing that makes the single just trounce the stock set up ... witch in reality is easy to beat ...straaying away from this is something lesser ....ive read what others have posted of there pipe set ups ..most say its almost as good as stock ....that tells me pipe manifolds hurt the flow big time ...to me the heart of the system that has the biggest bang to the motor is where carb is at and getting it all right there ..as for the right plan ... not trying to discount just speaking my thoughts for you to go over ... i also like the no stock intake horns as huge also ...like your doing ... i have a vision of what i want but havnt found the right stuff or funds to try and time also ...but it will start at the carb as main focas ...to make the perfect runner collector
 
I agree that anything other than a properly set up set of 1 carb per cylinder will always beat a single carb's performance. I also say 4 30+ year old carbs will never match the dependability and low cost of a single, commonly available automotive carb.

If I wanted a high performance, footpeg-dragging 0-to-60 in 3 seconds ride I wouldn't be messing around with a >30 year old Goldwing.

What I want is the Ford F150 of motorcycles. One that I can turn the key and it will run and not cost an arm and a leg when something does need to be fixed, that I can find scads of used parts for. A SHTF bike that I can ride for years to come even if civilization as we know it fell apart tomorrow. I believe the 1980s Goldwing is that machine and its only weakness is those four carburetors. And I've seen no other bike that it is even possible to replace them with a single and forget about it.

I have the luxury of having another very quick and fun little screamer for when I want to ride like that. My Goldwing will be the 2 wheel version of a pickup truck. If I could figure out how to make it 2WD I would.
[I know 2WD bikes exist and have studied how they work. I'd love to build a Ural-style driven sidecar for it.]
 
no way a stock honda set up of four carbs will beat my bike ask anyone that has rode with me ....and as for dependable and run at any beckin call ive got that too ....

there is no way the myth of the stock honda carbs will always be better than an single ..will not live here on this forum we deal with truths not fiction and fantasy .....

truth is the best stock rack around deprives the oldwing motor big ... mostly noticeable with no torque till 3000 rpm ...truth cv carbs were always a step down ,,, when a runner space replaces a carb ..its is like accumulator of perfect gas charge if carb is dial in right and will kick ass as its always ready ... the myths and total bs against this is just that ..FI in no way beats perfect gas charge ...like i said the stock carbs are the biggest hold back in power on a oldwing period .... ignition second ... you can think what you want ...but i just gave you the facts ... thats what we deal with here
 
I believe you that a really well designed manifold and set up carb can kick ass. I'm not sure it would beat a show room bike of the same year with all shiny new carbs straight from Japan. There's almost no way to test that without a dyno and track to see how the specs match those of the bike when it was new. You're comparing yours to 30 year old Goldwings with 30 year old carbs which validates what I think is true- 1 new clean well set up carb can work better than 4 old really ones. I don't know if it would beat 4 brand new ones.

You're saying it's possible to have both dependability and performance that equals or passes the OEM setup. I believe you. But there are reasons why racing boats and cars have changed stock singles to multiple carbs since the 50s. They are an expensive PITA but when they work right they beat singles almost every time when drag racing. It's a bit different when you want the power over longer time and RPM range. Look at the bike specs on the sales literature and they still give the 0-to-something time in tenths of a second. A second faster sells more bikes. That's the way a lot of bikes (and cars) are designed to this day: as drag racers. If you want that push you into the seat hang on acceleration until the 90s and fuel injection at each cylinder became easy, you needed multiple carbs and runners as short as possible. You also didn't care if they dumped in excess fuel. Now that's a no-no.

I would really like to see if Honda messed up and a single really does give better performance than a new set of 4 OEMs. Can you imagine if they had originally sold it with only one carb? For starts we wouldn't be having this conversation!
 
well untill this yr and it was political pressure that changed things nascar has used the basic single carb set up ... the power it takes to run these heavier than all race cars is huge ...and the power so great they used restrictor plates to cut the carbs back ... like the race today at talledaga if you had a four barrle carb non restrictor plate car ...it would trounce these fuel injected corn gas cars that will be running today bigtime ...and the these races are long and they have to be reliable ...the cars there running this yr have blown up everywhere this yr ... they are not talking much about that LOL...

so even that argument dosnt hold water....at the drag strip strait carbs on top of blowers are still the king and have been for decades 50 yrs actually more ... hype about someting is not results in any way

there are no cv carbs at the drag strip ..that are king of anything except a class of there own ...as i see it ....old tech actually rules in spite of all the press to belittle it

now to get this this briggs atratton power house carb to work on my yard vac today ...LOL....you would think in todays thinking this is the best a carb will do :smilie_happy: :smilie_happy: :doh:
 
I've already posted my opinion of this 'debate' so I won't post it again here:
viewtopic.php?p=133398#p133398

I'm more interested in seeing Chuck's copper build come to life in this thread.
 
Yes, I don't want to continue debating it. I'm shooting for it working well and being dependable. If I do another wing (and what are the odds of THAT, really?) I might go to the extra effort and expense to have tubing bent and make the best manifold possible, and maybe use a different carb.
 
I really doubt that the copper will need to flex. If you use the 1 barrel single you probably want it on a 3" riser like the stock VW had. Yes the motor does expand when it's warmed and copper will expand more (slightly) with the same heat. But being above the motor it will not be affected by the same amount of heat. In light of that I'd silver solder it together use some good heavy gaskets to mount to the heads and go from there if I were doing it. I chose to buy tools over buying the more expensive copper.
 
I don't think flex will be a problem either with regular plumbing solder as long as the fittings are very clean before soldering and you use good flux.
My favorite is tinning flux, it flows nice and sets a nice tinned bed for the solder.
Stick silver solder is nice though. It fills and layers much better than plain solder.
 
I can only find 90, 45, 22.5, and 11 degrees and they are a couple bux each. 90 Tees are everywhere but 45 wye fittings are rare and expensive, like $13 each. Since I just can't get there with off the shelf angle fittings in either PVC or copper, I've been looking into bending. Over in old England it seems to be common practice to bend copper plumbing where possible because it's faster, cheaper, and two less places to leak. Makes sense. They have internal bending springs for this but I can't find them in US sizes. But if I can find any plain old spring that will fit snugly into 1" it should work. Another way it's done is by filling the pipe with fine sand or salt and crimping the ends. These are both to keep the tube from collapsing when bent. Heat can also be used.

This will make nice gradual bends ideal for flow. I'm going to tinker with designs using a mix of bent tube and standard fittings to see what they look like.
 
Top