Last "Schlup"date: April 10, 2012

(4/29/07) Back in 2004 I found myself in a predicament. The stock carbs on my GL 1100 had been built and rebuilt so many times that they were simply worn out. I checked around and the cheapest set of rebuilt carbs I could find were $200.00 plus shipping! My income leaves a bunch to be desired, and I set off to find a cheaper alternative. My solution was to re-fashion the stock air box which the carbs bolted to into an intake and mount a cheap one or two barrel automotive carb on top of it. The yah yah you'll find throughout these pages chronicles my attempt to find a cheap alternative to an otherwise expensive problem.


4/21/2004- Well, I guess yer here because you're wonderin' jus' what the hell does this dumbass mean by a plastic intake manifold for Goldwings... Either that, or you're WWWAAAYYYY too bored and should get out more often... Either way, and since you ARE here right now, this is my page dedicated to my on-going attempt to make a plastic (or at least partially plastic) intake manifold for my raggedy 1980 RATwing...

I have always experimented with "alternative" (ie: CHEAPER) ways of handling problems related to keeping my Goldwing(s) on the road (My stator-to-alternator plans page being one example).....And necessity being the mother of invention (or so I hear) I am in the process of building a four carburetor to one carburetor conversion for my ol' wing... Now, let me tell ya'... **There are single carburetor conversions already being made for Goldwings out there, so my idea is NOT unique. However, all that I have seen are cast aluminum and ALL are way too expensive for my public school teacher's wallet. The cheapest intake, minus the carb, that I have found has been $150.00! It sure is pretty, though, all shiny and smooth..........BUT who cares if it's shiny and smooth??!! The doggone thing sits under the faux gas tank!

** I use to have a link to an outfit called "Cycle Innovations". They use to sell an aluminum intake and carb assembly for about $500.00 but the link went bad and from what I hear, they have gone out of business. As far as I know, there AREN'T any (factory, at least) intakes being made. I have since become a member of a MSN Group called Backyard Built Goldwings. I recommend paying those guys a visit as there are some pretty neat home made set ups listed there as well.

MY idea is to take a stock Goldwing airbox (the doo hickie that the air filter bolts to), seal it up air tight, fit FOUR inch and a quarter pieces of intake (PVC) pipe in between it and the heads and slap a single barrel (150 cfm or so) carburetor to the top of the box in place of the air filter. Shaking yer head, aren't ya? Well, I never claimed to be rocket scientist but if you look at the dimensions of those so-called "professional" manifolds, the air chamber which the carb sits on is VERY similar in size to a stock goldwing airbox.

Instead of casting the intake runners into the air chamber, though, I propose using 1/2 inch thick flat nylon to block off the stock carburetor mounts in the air box and then cutting inch and a quarter holes in place of each "stock" hole, to which I am going to insert about a four inch section of "Schedule 40" PVC pipe. I'll seal everything up with silicone and the PVC pipe should slip into the existing aluminium intake pieces at the heads and snug up with the existing clamps. Heat should not be a concern as the intake actually sits above the engine and keeping the PVC lengths short will aid in their ability to support the air box.

This is all in the "what if" stage right now, but to date I have a total of $2.35 invested in this process (for a 6' length of PVC). I'll update this page as I go along... Wish me well because if this works, I am CERTAIN there are other tight wads out there like me with too little money and too much time willing to convert to a single barrel carburetor instead of paying $$$ for somebody to try and clean and synchronize their old drippers, or pay beaucoup denaro for some fancy schmancy "professional" job. =)

Got questions or jus' wanna' email and tell me what a YUTZ I am? G'head... I'm a glutton for punishment! =)

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July 22, 2004-- Just won an eBay auction for a rebuilt Holley 2 barrel carburetor for the "bargain basement" price of $50.07! The carb is a 2110 and according to my handy dandy calculator and box of crayons, should flow about 165 CFM. My only worry about this carburetor is the width/ length of the carb base. I was shooting for a single barrel Holley or even Stromburg, but the ones I could find were either VERY old and worn out or VERY expensive (or both). I have two extra stock carb sets (GL 1000 and GL 1100) which should pay for the development costs of my "new" intake... More to come! YEE HAA! =)

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I have finally progressed to the point of mock-up of the intake "plates" and mounting of the Holley carburetor. If all goes well, placement of the nylon adaptor plates and carburetor mounting plate will come soon!

This is the rear of the intake with plates attached. Instead of having a carburetor mounted at each point, a straight piece of PVC pipe will run to the stock aluminum "elbow" and into the head. You will notice that the perch for the accelerator wheel and choke are ground off. I may end up grinding off the "foot" at the bottom of the picture as well.

The Holley 2110 is almost a perfect fit into the stock air box opening. A thicker piece of nylon will be cut and utilized as a mounting plate between the carburetor and intake.Stay tuned for more developments!

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Second Mock- Up

Over a year since suffering a brain cramp and coming up with this weird and wonky thought about throwing out the metal and embracing polyvinylchloride, the second mock-up is made and ready for fitment!

Ain't she pretty!!?? A mug only a mother could love, huh? The original air box is the silver hunk surrounded by the slabs of white stuff. The slabs are 1/2" nylon "blocks" (similar to what cutting boards are made of). The intake runners shooting off to the sides are simple 1& 1/4" PVC pieces cut to 4 inch lengths. The blue goo is good ol' RTV blue silicone sealant. The challenge to making this thing, and keeping it running is to turn an "everyday" (leaky) air filter housing into an airtight assembly. Hence, the tube of blue goo...

Side shot giving a better view of the carburetor flange. The stock air filter housing has two bolt holes sunk in at opposing corners which normally hold the air filter assembly together. After cutting the dimensions of the flange, a good friend, Big Ed (and one HELLUVA Harley builder), drilled a hole into each corner. He then countersunk two bolts (the blue circular spots) into the stock bolt holes and then double threaded two flange bolts on opposite corners (bolts sticking up). The carburetor came with a very heavy, cast iron intake flange, making fitment of the carb to the nylon flange "do-able" with only two bolts.

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What's it cost to build the damn thing!?

Long Term Test Update (added 1/27/2007)

Results from first Shake Down run: High Speedadded 6/11

Results from second Shake Down run: Low Speed/ Around Town (added 6/12)

Long Term Testing in Progress... 100 Miles Down... No Problems! (added 6/14)

Lon Term Testing Continues... 1,000 miles Down... No Problems! (added 1/27)

Dateline June 7th, 2005...The intake (affectionately known as "Frankentake") is in place and operational! DAMN! She sounds good!!!!!

Finishing touches included sealing the carburetor flange into place with RTV blue silicone, and squirting the whole she-bang with high dollar (ninety-nine cent) flat black paint straight from the rattle can! Ya' jus' can't beat the look of flat black and polished aluminum!

As you can see, the assembly really doesn't look all that bad painted flat black and partially hidden from view. The carburetor sits sideways on the intake, placing the throttle and choke assemblies at the front near the radiator and the idle adjustment screws conveniently located the side of the arrangement. The large black hose at the left is the fuel line running from the stock fuel pump up, up, up to the fuel inlet near the top left side of the carb. I was concerned about the pump pumping, but so far it's doing a good job. The smaller black hose at the bottom middle of the carb is the hose running to the vacuum advance.

Better shot of the fuel inlet. The carb sits very close to the top frame rail. I was concerned about it rubbing against the rail over time so "fixed" the problem with my small sledge hammer by "squishing" the frame rail over a tad. =)

You can see my handy work just behind the regulator/ rectifier (I removed it before wacking off on the frame rail) =)

Not bad looking, huh? God, it sounds great! Reminds me of the big block Impala I had as a teenager! The throttle response is just amazing! Franentake lives, but the SHAKEDOWN has just begun...

Next step: Grabbing my cell phone (just in case) =) and burning the rubber of the thing to break it in... Or just break it? Long term concerns center around my ability to completely seal the intake and keep it sealed. It should be interesting to see how the PVC and Nylon holds up to time, temperature and fuel... More updates to come!

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What's it cost to build the damn thing!? Updated 1/27/2007

So far, this has been an extremely affordable endeavor... Piece-by-piece costs are:

  • 3 tubes of RTV Blue Silicone (re-gooped the intake after 1 year...added 1 tube of RTV)-$12.00

  • 36 inch piece of 1 & 1/4" PVC--------------------$2.35

  • Holley Model 2110 Carburetor(with shipping)--------$62.00

  • Rattle can flat black paint-------------------------- .99

  • Miscellaneous bolts & such (scrounged at home)-------free

  • Nylon plates cut from scrap (found behind food store)----free

  • Fuel line (left over at auto parts store)----------------------------free

  • Air Breather Assembly (junk Triumph part)---------------free

GRAND TOTAL----------------------------------------> $77.34

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Shake Down Run #1

Dateline June 11th: Spent the morning making a throttle cable mount and choke mount for the carb. Both came out remarkably well using junk laying around the house. I utilized the Holley's stock accelerator assembly and ran the "pull" cable to one end of it and a small spring to the other to act as a "counter". Removed the "push" cable from the throttle and threw it in the pile of other goodies I don't need anymore and began fabricating the choke cable. Used a choke cable and assembly from a junk Honda CX 500 (Similar to the choke assembly found on a Goldwing). Fired up the grinder and fabricated a mount which is bolted to the lower frame rail in between the right side intake runners. After making sure choke and throttle operation were spot on I fired up the bike and WOW! I never thought adding a different carburetor set up would have THAT much of an effect on a motorcycle... To be fair, the old carbs were pretty shot, but it was like riding a brand new motorcycle. Top speed was somewhere at, around, or over 100 mph (stock speedo gauge only goes to 85 so that's an estimate) and I hit 65 in second gear.

Some people who have attempted a similar conversion using a Volkswagen carb have complained about a rough idle as the bike "loads up" if sitting for too long. I calculated the CFM and the Holley 2110 is a bit larger than the stock carbs altogether (about 165-175 CFM) but shouldn't load up all that quickly if I added and subtracted right. I didn't give the critter much chance to sit and idle today =) but am planning on riding the bike into town tomorrow morning (God willin' and the creek don't rise). Played around with the fuel/ air mixture screws to drop down the idle a bit (that may be something to work on as well). Stock air box (now manifold) seems to be holding up well. I was amazed after "flogging the dog" as hard as I did that the intake runners and manifold/ carb combo were nice and cool at shut down... The REST of the bike sure wasn't! =)

Shake Down Cruise number 1 is "officially" in the books... Now lets' see how she does in a more "civilized" manner around town.... More to come soon.

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Shake Down Run #2 (added June 12)

Sunday morning dawned hot and humid with storm clouds on the horizon and I debated on whether to tempt fate once again and continue with my shakedown of the new carb/ intake combo. I burned a little sage to dispel the evil spirits, said a few words to Wingolana, Goddess of Goldwings, and swung a leg over... The bike fired to life at the touch of the button and I (literally) was able to idle without choke after about 30 seconds. The bike performed well around town. It DID load up a couple of times at the longer stoplights but the bike didn't quit and I was able to "clean its throat" with a couple blips of the throttle. I don't mind the bike loading up a bit and may just leave the fuel/ air mixture alone for now. Off idle acceleration from stops is just amazing! I was running a set of GL 1000 carbs on my bike before this transition (no accelerator pump on the older carb sets) and there is a world of difference between the stock carbs and the Holley. The most "niggly" concern I have is a very high pitched whine from the carb throat when I get on it a bit. All in all, I am very pleased and more confident in the carb. intake assembly after today... Long term experimentation will determine if this design holds up or becomes troublesome over time. I'll keep you appraised at regular intervals. Until then, I can recommend this design as a viable alternative for mounting a single carburetor in place of the stock originals...

Choke knob is peeking out under tank shell.

Long Term Test Update (addded 1/27/2007)

It's been awhile since I updated this page with the on-going results of my carb experiment. Since the conversion, I have put just over 1,000 miles on the Goldwing. The bike is still running like a champ. In fact, it is running better now than it did when i first completed the conversion. This is due, in part, to a small intake leak which was sealed this past spring which had developed between one of the nylon plates and aluminum airbox. As you may recall, I "mated" the intake runners to the stock airbox through the use of nylon plates held in place with screws and lots of blue RTV. Over time, the nylon has cracked in a few places where the screws go through the nylon and secure the the nylon to the aluminum body. The nylon cracked allowing a small intake leak to develop which cause rough idling to occur. I re-tourqued the screws holding the nylon in place and bought another tube of blue RTV and gunked the whole she-bang up again. Since the spring, the bike starts in an instant, idles without choke in literally seconds and SCREAMS down the road. I plan on removing the manifold again this spring to check for any additional cracking, but I started the bike up this morning and she ran just as well as she did when I parked her for the winter. I'll tell you, this is one conversion which I have been very pleased with.

Long Term Test Update (addded 7/27/2009)

With about 7,000 miles on the carb setup, I have to say that I continue to be impressed with its performance. The bike has actually smoothed out a bit the more I have ridden it. I recently bought a '82 GL 1100 Aspencade (stock engine with about a ton of chrome goodies on it)... OH MY  GOD, what a SLUG compared to my rat! The combination of the bags and extra "garbage" on the bike coupled with stock carbeuration definitely makes it a "tourer" and not a "go-fast" critter. I LOVE ridin' FUBAR around town and on Poker Runs. It sounds grat and gets looks and questions all of the time. The garbage wagon will stay stock. A carb rebuild kit from Randakk's Cycle Shop (not cheap but from what I hear, worth it) should bring the garbage wagon closer to the performance of FUBAR. I do not regret this conversion at all! =)

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Long-term Updates and Close-ups of the Carburetor Assembly

Carburetor close-ups

The following pictures were taken after I modified a junk Triumph Air Breather Assembly to fit the caburetor throat... I added the "Triumph" points cover to the top of the assembly because, while my raggedy Goldwing will never be confused with a Triumph, it IS a triumph to actually see an idea (crazy as it may be) come to fruition. Folks, I have put all of this information on to the site not to brag or show off, but to show that it CAN be done... And be done by "Joe Schmoe"... I am NOT a mechanic, metal fabricator or anything like that, and I was able to make this critter work, so YOU should be able to do the same. If you think you want to try something similar, please feel free to zap me your questions. I am more than happy to help with anything I can.

This is "head on" view of the carburetor as seen front-to-back. The throttle and choke assembly are located at the "front" of the carb. As you can see, there is nothing "special" about my work... I believe in the power of zip ties, Blue RTV and bailing wire. =)

Running a throttle "counter" spring to the throttle assembly allowed me to get rid of the "pull" cable to the handlebar control. It gives good feedback and feels almost the same as the stock throttle at the handlbars. The choke assembly is run to the lower frame rail on the bike. It's pretty convenient and hardly noticeable, but I keep wanting to reach up front to where the stock choke was placed. =)

This view is "back to front" as seen from the saddle. The vacuum advance and air/ fuel mixture screws are located on the right (fuel pump side) of the carb making adjustments very easy. The fuel inlet is at the very top of the carb assembly... As I wrote before, I was concerned about the stock fuel pump's ability to pump fuel so much farther and higher than with the stock carb set, but it has not been issue. The only "modification" I made to the bike frame is to hammer the top frame rail over a bit to make room for the inlet valve. Look just below the "Air" tag and you may be able to see the squashed frame rail. I probably could have moved the entire carb assembly over to the right by making the intake runners longer on the left side and shorter on the right... As it is, the assembly is hanging solid and without any noticeable defects.

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Long-term Updates

I'll try to keep this area of the site updated weekly until I am convinced there will be no sudden or catastrophic problems with this arrangement.

Added: 6/14/05-- I have a total of 100 miles on the assembly as of today... Noticeable issues so far are limited to an off-idle stumble after I sit at a stoplight for some time. The carb is loading up a bit, and stumbles from time to time at take off. So far, a quick "blip" of the throttle has cleared the problem without additional issues. I added a home-made air breather today and am hoping it will help restrict air flow a little bit, helping with the loading up problem. I have previously downloaded Holley's service manual for this particular carb (Holley 2110), and it has a detailed section on adjusting the fuel/ air mixture... This will be my next task before taking the bike back onto the road. I am confident that I can get the air/fuel mixture straightened out soon. Even if the carb continues to load up while idling, I am very, very happy with the results so far and plan to keep riding the wheels off of the bike. More coming soon!

Added: 6/17/05-- So far, so good... Found a small intake leak at the rear of the intake manifold. Added more blue goo and it looks good and back to running fine... Having thoughts about "sealing" the inner part of the intake manifold with some sort of impermeable coating. It looks like left over gas is "pooling" in the bottom of the manifold and "eating" through the blue goo making a leak... I'll have to nose around for stuff. The fun continues! =)

Added: 7/8/05-- The whole reason I decided to try and build an "alternative" intake was to see if a common guy or gal could put something together "on the cheap" and have it work out... So far, my experiment has worked out great! To date I have racked up about 600 miles on the set up. It seems to be holding together well, but there are a few things I would do differently if I did it all over again:  

1. I bought a Holley 2110 carburetor off of eBay cheap... The carb itself is working just fine, however, I must have made a calculation error when trying to figure out how big a carb I could use. I thought the 2110 would work just fine, but it tends to "load up" if sitting for more than a few minutes, or at longer stop lights. This isn't much of a problem for me as I can keep the bike running at a stop by blipping the throttle, but it is obvious that the carb should have been smaller. My next modification will be to order a smaller main jet for the carb and see if I can jet her down a bit. On the other hand, I have NEVER had another motorcycle launch as hard and run so quick as the wing does now. One of my other project bikes was a KZ 1000 P-4 (Police Special) that had oodles of engine work done to it when the cops had it to make it go fast and I use to say that it was THE fastest, and quickest bike I ever rode... The Goldwing, stripped down to nothing and with the big carburetor, beats the Kawai hands down. It's super quick and I could not be more pleased when she's up to speed.      

2. I have had one intake leak so far... The leak was located at the rear of the intake and I suspect it was seepage through the rubber gasket where the two halves of the intake bolt together. Originally, I used Blue RTV to "seal" up the intake, but after a few days, and when I noticed the leak and removed the intake, it was obvious that fuel was puddling at the rear "floor" of the intake and then deteriorating the RTV Blue. The makers of RTV say its good at gaskets but to avoid continued and long term exposure to fuel, so I took the intake apart and used Indian Head Shellac to seal up the halves and THEN coated the external manifold with a think layer of RTV. To date, this mod has worked without any problems. Fuel still puddles (and probably will until I jet down the carb) but it has not seeped past the Indian Head Shellac. THAT stuff, by the way is worth its weight in gold, if ya' ask me... I have re-used MANY head gaskets over the years by glopping good ol' Indian Head on the gasket before re-installing it. (Good stuff, Maynard!)  =)      

3. I figure the PVC pipe will become brittle over time and may start to crack. Some friends have told me to expect this and I will probably scrounge some inch and a quarter steel tubing from somewhere and replace the PVC with it over the winter. On the other hand, it would be neat to see just how long all of that plastic holds up. =)

Added: 7/27/09-- MAN! I can't believe it's been four years since the intake has been on the bike! Aside from some "niggly" problems (small intake leaks), the intake and carb have performed very well. If you're mechanically inclined, and dollar short (like me), you might consider building an intake similar to mine. = )

Most Recent Goodies!


After seven years of dependable service, the time has come to overhaul my original design. All things considered, the intake has held up extremely well. The side nylon plates have cracked at the bolt mounts, but the PVC intake runners are in remarkable condition. The bike still ran well at speed but it finally got to the point that it would not idle properly. My guess is that it was sucking too much air through one or more cracks in the nylon to maintain adle but once the throttle was opened up, the problem diminished. When I first sat out on this intake journey, I was hoping for a year or two of worry free operation. Instead, I was able to get 7 years and about 35,000 miles of operation from the setp. Additionally, I could have removed the intake, re-gooped the manifold with RTV Blue and probably gone another year or two with the original set up.... Not bad for a throw-together idea and an eBay carburetor. =)

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The saga continues! Almost 3 years to the day, I have removed the plastic intake from my bike for a thorough "look-see". Prior to this removal, the intake was removed about once per year for inspection and to seal up any leaks which may have occurred. I was afraid that the PVC pipe would become brittle over time, but it has held up extremely well. The nylon "plates" connecting the PVC tubes to the aluminum intake housing has split in a couple of places and I have found a few intake leaks with this last removal. I purchased some gas tank sealant which seems to be some sort of epoxy-in-a-stick and will use that to fill any gaps (Cost about 3 bux). It dries in 2 hours and cures in 12, so in a day or so I will place a fresh coat of RTV blue sealant over the repaired areas and see how it holds up.


Click the pix for a "supersized" look. Images will open in a new window.


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Well,   five years after I got ths crazy ass idea, and 4 years of actual operation,  I am happy to report that "Frankentake" is aging well. Inspection earler this year of the carb and manifold showed no increase in the stress cracks noted earlier. The carb is holding up well and I plan on disassembling it next spring to give it an internal inspection. The bike is running GREAT! Here's a shaky video of the bike running from this morning. Sorry for the low quality but I was trying to shoot and operate the bike at the same time.

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