• Can't post after logging to the forum for the first time... Try Again - If you can't post in the forum, sign out of both the membership site and the forum and log in again. Make sure your COG membership is active and your browser allow cookies. If you still can't post, contact the COG IT guy at IT@Concours.org.
  • IF YOU GET 404 ERROR: This may be due to using a link in a post from prior to the web migration. Content was brought over from the old forum as is, but the links may be in error. If the link contains "cog-online.org" it is an old link and will not work.

Carb overflow conversion

M

MD634281

Guest
Guest
Hi, I'm trying to find out about the carb overflow modification. I've tried to contact Shoodaben but the email comes back as wrong.
I'm in the UK and due to circumstances (and shipping costs) cannot afford to send them to Steve: even if he still does them! :oops:
I just need to know the length of the brass tube, in order to do the job, I've got 4mm brass tubing already, and other sizes. for my model making pastime.
Thanks everyone!
 
Steve has replied to my post: amazing how spelling out his email address correctly helps.... šŸ¤£
Thanks again Steve
 
I've read there are other float bowls that will fit the C10 carb that has the over flow tubes factory installed. I forget which models these came from but might be worth serching for. I know some members and Subcribers have the ability to install over flow tubes themselves if given the right specs. For me looking on ebay for float bowls already installed would be an option if the bike could not be down for long or in this case difficult to get to Steve.
 
I cannot find any reference to alternative float bowls, but in my case the best option is to modify the ones I already have. I'm a lifelong model maker, and have lots of brass tubing I can use. Following from Steve's input, I can carry out the work myself, and at just about zero cost (y)
 
I Did: "I believe Kawasaki Voyager bowls will fit and they may have overflows" I understand this is what others have found to work. Be asured if I'm wrong others will chim in.

I have no doubt you can make a brass tube work after Steves input.
 
I've come across another issue. The 2 'left carb' bowls are different to the right pair! At first I thought they had been replaced by a previous owner, then when searching ebay, I saw a set of carbs for sale that were exactly the same. one pair have the drian screw 'inside' the bowl, the screw cut to remove them being flush with the bowl casting, on the other pair, they are longer screws that protrude about 20mm beyond the bowl...very odd!
These are UK bikes, both later 1994 A9 facelift models.
 
mikedenny634281 said:
I've come across another issue. The 2 'left carb' bowls are different to the right pair! At first I thought they had been replaced by a previous owner, then when searching ebay, I saw a set of carbs for sale that were exactly the same. one pair have the drian screw 'inside' the bowl, the screw cut to remove them being flush with the bowl casting, on the other pair, they are longer screws that protrude about 20mm beyond the bowl...very odd!
These are UK bikes, both later 1994 A9 facelift models.
Click to expand...
This is normal. Both my 99 and 05 have the same thing. If you look at any online parts site you will see that the drain screws are different.
 
Thanks for the update Jpd, I wonder why?
I've completed the carb bowl overflows today, pretty easy (with Steve's input!) I'm waiting on some liquid epoxy so that I can seal up the tubes properly, I tried the epoxy putty I bought but I'm doubtful its going to last. I also cut off the tips from the drain screws, I'm going to glue these 'blanks' in, to block any leaks through there. Pictures to follow of course! ;)
 
I
mikedenny634281 said:
Thanks for the update Jpd, I wonder why?
I've completed the carb bowl overflows today, pretty easy (with Steve's input!) I'm waiting on some liquid epoxy so that I can seal up the tubes properly, I tried the epoxy putty I bought but I'm doubtful its going to last. I also cut off the tips from the drain screws, I'm going to glue these 'blanks' in, to block any leaks through there. Pictures to follow of course! ;)
Click to expand...
If you cut the tips off the drain screws you just screwed yourself. Now the bowls will empty as fast as the fluid goes into them.

One thing I've seen for years with stunning regularity when doing carbs, is the ability for folks to think of new ways to damage their carbs in an attempt to save money. With Stunning Regularity.

Steve
 
How is that Steve? The brass tube passes right though the original overflow port. I drilled out the centre to take the 3mm brass tube, but stopped about 1mm short of the end. This gave me a seat to set the brass tube. I then filled the drilled hole with epoxy, pushed in the brass tube, then ran a 2mm drill back through the tube to clear out any trapped resin. Looking into the original drain screw hole, I could see the brass tube, then I cut off the drain screw tip, and screwed it back in, with threadlock added. Seals perfectly. Nothing stunning at all: as I said earlier, I've been doing work like this for years, then with your much appreciated advice, I have perfectly sealed carb bowls. (y)
 
How do I add a picture from my laptop? This post needs pics!
 
Hope that works! Sent to my photobucket a/c then copied :oops:
I cut a slot into the drain port so that I could get a key on the epoxy, rather than just have it on the outside
 
The drain screws are still active and need to be there. The overflow tubes go into the drain from the top after the tip of the screw plugs the hole in the side of the drain boss.
 
I think I see what you mean. I blocked the hole in the bottom of the float bowl with epoxy, then the new overflow tube drops into the newly drilled hole. On the outside is where the drain screw fits, rather than fill this side with epoxy, I cut off the tapered section and refitted it, with a coat of threadlok.
 
The way I've done it means I no longer have drains should I ever need to empty the carbs bowls: not a problem! In the 40+ years I've been riding and modifying big Zeds, I've not faced such an issue. If the carbs overflow, I'd soon remove the full set and service them on the bench šŸ˜‰
 
The brass tube isn't supposed to intersect with the screw drain hole. It's supposed to stop above the drain screw, so if the fuel overflows it flows AROUND the side of the drain screw and out the bottom drain nipple. To my knowledge I've never seen or heard of anyone doing the mod as these were done.
One real concern I have, and have had since the beginning of doing these tube installations, is the use of epoxy. the cleaning agentsin toadys fuel are eating all the epoxies folks have tried. The only right way is a press fit.

At one time there was a great brain trust in COG, borne of our many experiments and labors, and everyone stood to benefit from it. Unfortunately that brain trust has been relegated as "old news" , "insignificant" , and put to pasture. Lots of knowledge on the c-10 has gone with it, and more will disappear as the days go by. This is the law of "unintended consequences" and everyone is worse for it. But hey, maybe those new young members COG is wooing will fill the knowledge void... though that seems pretty unlikely.

Steve
 
Ok Steve, any ideas as to why my first test bowl is still holding fuel? I've not fitted it to the carbs yet as I'm waiting on the new epoxy to arrive, to seal the other three.
I think the vibration and heat when in use will change things!
 
I must confess that right now I'm totally lost! I cannot see how excess fuel can escape from a tube that is above the drain hole/plug. I think that the way I've fitted the overflow tube will work, in that when the float valve sticks, the fuel, instead of flowing into the intake, it will just flow out of the carb bowl, and out into the overflow tubes, now fitted...just like the old carbs did!
I'm assuming the float bowls work at normal air pressure of course šŸ‘
 
Steve, what's your thoughts on the solenoid solution? Just curious why others haven't come up with this simple answer.
 
After reading the replies, I think I now see what you mean...I'm 58 soon, so need a little more time!
My version of Steve's mod will work, I'm now sure of that, but I won't have the ability to drain the bowls via the original drain screw.
I've fitted stainless steel Allen head screws to the bowls, so if the need arises I can easily remove them in situ, plus I've replaced the rubber inlet stubs with new genuine parts: many years of trying to remove/refit carbs held firm by 25 year old solid parts taught me well šŸ˜
Don't believe the soaking in Winter Green/Witch Piss/Unicorn semen myths...just buy nice new soft bendy ones and never look back šŸ˜‚
 
Freddy said:
Steve, what's your thoughts on the solenoid solution? Just curious why others haven't come up with this simple answer.
Click to expand...

Other have come up with that answer 12-14 years ago. JD Mullins was a proponent. I tested a shut off solenoid for Murph. We ultimately decided not to move forward because to much resistance to flow in a gravity fed system was causing low fuel flow and carburetion fuel starvation issues.

Again, this is what I'm talking about. we've BTDT. Prolifically in the time from 2005 to 2010. I haven't seen anyone since that time better anything the active COG members on this forum developed and contributed. Yet sadly, it appears all that information resides in the minds of a few legacy members and no value seems to be placed on retaining these folks.
 
I've had no issues with fuel starvation on either bike with the above solenoid, perhaps they have much less restriction these days.
 
If you filled the drain hole. How do you check the fuel level in the float bowl? Don't you need to have a clear drain hose on the bottom nipple and check the fuel level against the bowl split line.

My concern is you removed a mechanical shutoff for the drain and are replacing it with epoxy. Most fuel proof sealants are very expensive. Also now if you get a shot of bad gas you can't drain the carbs and have to spend a couple of hours removing and cleaning them instead of just opening the drain screws. If you had a bowl drain that wouldn't seat and seal then your option will keep it going without replacing the bowl with a new one.

I have seen posts on manual SOV and Solenoid valves, and although they work they can fail just the same as the original vacuum one. You still need to have the overflow tubes installed to tell if you have the second failure of a float valve that can lead to hydro lock.
 
Having slept on it, I now see what I should have done. :oops:
The brass tube goes into the drilled hole, and basically sits against the drain screw: this seals at its tip, so the brass overflow allows excess fuel to flow past the drian screw as its not sealed at this section....is that correct?
'my' version still works, but I've lost the drain function, so I'll drill out the brass tube from the drain hole and replace the drain screww I cut down.
Thanks again everyone (y)
 
The
mikedenny634281 said:
Having slept on it, I now see what I should have done. :oops:
The brass tube goes into the drilled hole, and basically sits against the drain screw: this seals at its tip, so the brass overflow allows excess fuel to flow past the drian screw as its not sealed at this section....is that correct?
'my' version still works, but I've lost the drain function, so I'll drill out the brass tube from the drain hole and replace the drain screww I cut down.
Thanks again everyone (y)
Click to expand...
The brass tube cannot reach down enough to touch the drain screw, or the screw will impede flow. Shouldering the hole for the brass tube is difficult and not necessary. Epoxy is an accident wating to happen. That leaves 1 option, a proper press fit. And the tube needs to be a min of 8mm above the parting line with a max of 10mm. Anything less than 8mm is going to have fuel sloshing over during ordinary operation, and if you exceed 10mm Then the intersection with the main air correction jet becomes a possible source of fuel running into the airbox.
OH, and the tube needs to be installed so that the float cannot touch it at any point through it's movement, or it will cause fuel level and shutoff issues.

Steve
 
Last edited:
mikedenny634281 said:
thinking of doing this: M3 x 0.75 thread, with loctite added, done on a test piece of alloy and a 3mm brass tube offcut.
Click to expand...
mikedenny634281 said:
thinking of doing this: M3 x 0.75 thread, with loctite added, done on a test piece of alloy and a 3mm brass tube offcut.
Click to expand...

Here we go again. Why not just go to the next size larger brass tube, and follow the info I've provided? That would be the best way to save your bowls. Now that may be a moot point, because you need drain screws, and the only way you're going to get a set is by obtaining another set of 4 bowls... and then you can start over with a proper press fit.

Steve
 
I haven't got any means to press the tubes in, thats why.
And as I've already drilled 3.0mm holes in the bowls, I cannot use M3.
Thats is why I've opened them to 3.2mm, and tapped to M4 x 0.75. I went up to 3.5mm brass tube, again tapped to M4x 0.75. It is easy to tap the bowls as the tap goes down past the drain hole, just threading the alloy above said hole. I watched for the tap protruding into the drain hole, ensuring I threaded enough. I'll thread the tube to the exact length, so I can tighten the tube into the bowl, using Loctite (which is solvent, oil, fuel and acid resistant). All I need is to buy one drain screw: or I could make one.
Job done perfectly, and I am much happier with threads and Loctite, as opposed to a pressed in fitting... ;)
 
Jpd11958 said:
I have seen posts on manual SOV and Solenoid valves, and although they work they can fail just the same as the original vacuum one. You still need to have the overflow tubes installed to tell if you have the second failure of a float valve that can lead to hydro lock.
Click to expand...

These solenoid valves are from LPG dual fuel systems. To fail in the option position would be near impossible as the valve is 'spring loaded' to close flow. As for it to fail in the open position simultaneously with the petcock and float valve I think I'd have better chances of winning a lottery.
 
Freddy said:
Fit a 12v fuel solenoid and save yaself the hassle - so simple and just as effective.

+1 what George said.
Click to expand...
I did the 12 volt fuel solenoid. My engine hydrlocked with it. Also I had fuel starvation issues with it as well. In the garbage it went
 
I usually find that trying to do something like this by myself I waste more time and money than
If I had spent it to Steve. Yes as a machinist I could pull this off by myself but finding the correct height
of the tube and a proper mandrel for pressing the tube in would take more time away from the other
thing I like to do. Some things should be left to those in the know.
 
rwulf, I agree but as I'm in the UK, the shipping costs and import duties, then Vat make it beyond my budget to send the bowls to Steve.
I've now finished my bowls, I've threaded the 3.5mm brass tubes and the bowls, and now added a stainless steel locknut to make sure they stay put, as well as the Loctite. I did all the work sat at my workbench, using parts I already had. Two of the holes were slightly angled, but I just eased the brass tube into the true upright position. I ruined one bowl (although I could still use it) but have bought a used bowl and drain screw for Ā£6 delivered. That is my total outlay, had I done the job properly in the first place it would have cost me about Ā£7.00 worth of stuff I already had.
 
"Loctite (which is solvent, oil, fuel and acid resistant)."

Not when submersed in fuel.

Please read up on it. You will need a fuel proof epoxy like Caswell uses for/as gas tank sealer.

Sure is a smart looking picture! Wish I had thought to thread mine. Just did press fit with Caswell for epoxy back up
 
Hi Mercer, the tubes and locknuts did actually seal the fuel without Loctite, well for the 24 hours test anyway! I think the M4 thread is so fine, plus the alloy bowl and brass tubes are soft so will 'stretch' , made a fuel-tight seal. The Loctite should hold up ok as its not actually sitting in fuel, but I must admit I was thinking the same as you. I guess I could also add a fibre washer under the locknut if a leak develops with use, but for now all is well...apart from the misfire, but I think thats fixed as well.
Bottom line is, getting Steve to do his conversion would have been easier, but I'm in England, and broke: can't work as we are under Covid lockdown again, so I had to do the job with what I had to hand, as stated earlier, my version cost me about $8 ;)
 
mikedenny634281 said:
Hi Mercer, the tubes and locknuts did actually seal the fuel without Loctite, well for the 24 hours test anyway! I think the M4 thread is so fine, plus the alloy bowl and brass tubes are soft so will 'stretch' , made a fuel-tight seal. The Loctite should hold up ok as its not actually sitting in fuel, but I must admit I was thinking the same as you. I guess I could also add a fibre washer under the locknut if a leak develops with use, but for now all is well...apart from the misfire, but I think thats fixed as well.
Bottom line is, getting Steve to do his conversion would have been easier, but I'm in England, and broke: can't work as we are under Covid lockdown again, so I had to do the job with what I had to hand, as stated earlier, my version cost me about $8 ;)
Click to expand...
Mike good day,
More than one way to skin the Connie frugal cats. Do like yours for the look of it. It was near impossible to find fuel proof seal, epoxy or otherwise. I did several tests on one bowl till I found Caswell tank sealer. Everything else would leak within a few days. It has been two years now and has not failed yet. Your way it could be heated unscrewed and resealed if ever a issue. Yeah I like that thread idea. But do agree Steve's is better, safer, and guaranteed! He has a jig set up I believe. Good luck!
 
Hi Mercer, once again I agree with your comments: had I been in the US, and had the money, I'd just send the job to Steve, without doubt.
But as that wasn't possible I set out to do the work myself: I've rebuilt this bike myself, like dozens before it, and am proud to have done so. But the biggest help I've had has been from this site, and advice from Steve on a few occasions, without which I couldn't have rebuilt this stunning bike šŸ˜
 
You can find fuel-proof (actually, just about anything-proof) sealants if you know where to look. The aviation industry uses a lot of them. I have experience with both PRC and Flamemaster products, which are excellent. GETTING them can be difficult unless you can find a local aircraft or automotive shop that has them or can order them for you. If course, the smallest kits you can get will do about 14,365 Connie carbs. Perhaps a really detailed search on the interweb could reveal smaller kits. And, yes, be prepared to fork over some coin, good stuff ain't cheap.

SEALANTS PRODUCTS BY PPG FOR THE AEROSPACE INDUSTRY - PPG Industries - Aerospace

Welcome to the introduction page of PPG Aerospace, a global leader in providing innovative and cutting-edge solutions for the aerospace industry. With a rich history spanning several decades, PPG Aerospace has established itself as a trusted partner and supplier to major aircraft manufacturers...
www.ppgaerospace.com www.ppgaerospace.com

Flamemaster Sealants, Heat Resistant Coatings & Contract Packaging | CS 3204 Class A, B & C

flamemaster.com flamemaster.com

When I did my overflow tubes I made sure they were press-fit and also added some JB Weld just in case. A few months later I had reason to take them apart and found all the JBWeld had come loose and swelled up into little grey doughnuts around the tubes. I got rid of it and rely on the press-fit, which has been holding well now for quite a few years.
 
I may have the answer to your question.
I recently rebuilt a 1912 Model T Ford Carburetor.
Being that old, the float is impossible to find. {They were originally made from cork)
So, I made one from fuel resistant foam.
I learned from a antique carb mechanic that they should be painted with Model Airplane Dope.
It works perfectly while submerged in my carb.
That Paint Dope can be purchased at any Model Airplane shop.

Ride safe, Ted
 
Ted,
That is amazing. Few people have been exposed to cork floats in carbs. That tech is long gone. Thanks for the Tip! Will give it a try someday.
 
Already had a look for some Dope. I build plastic model kits, I'm 57 now and still love building them, albeit much more expensive kits these days !
Should I coat the entire insd of the bowl? I'm thinking thats the way, so it seals, without me removing/resealing the oveflow tubes.
 
fyi; My Dad originally repaired and installed the carb about 30 years ago.
At the time, he coated the cork float with Varnish.
That varnish was all that was holding the float on the arm when I took the carb apart.
But, it lasted 29+ years before failing. (y)

NOTE: My repair didn't quite work (yet) so I installed a newer (1914) carb.
(I'm having to machine a replacement Needle for the 1912 carb. {ewwwww} šŸ˜µ
But, I'll eventually figure it out as we want the 1912 carb back on the car.
PS: The original Carb is a Holley..

Ride safe, Ted
 
Last edited:
mikedenny634281 said:
Already had a look for some Dope. I build plastic model kits, I'm 57 now and still love building them, albeit much more expensive kits these days !
Should I coat the entire insd of the bowl? I'm thinking thats the way, so it seals, without me removing/resealing the oveflow tubes.
Click to expand...
The "Dope" ted talks about was used in glow plug powered wood planes. It was used to cover the wood and back in the day, the wings were covered with a silk, light fabric or paper. The "dope " would make these materials form and strengthen the wing and/or fuselage. At the same time made the mess from a glow plug engine wipe off easily. I don't recall "dope' being used on plastic. As for todays U control or R/C aircraft modelers now use a plastic covering that heat shrink's. Iron it down on the wood and shrink it with a hair dryer. A Lot easier to deal with with no smell or brushes to clean.

Unfortunately the heat shrink stuff won't help here. But Ted's "dope Idea probably would stop leaks.
 
connie_rider said:
NOTE: My repair didn't quite work (yet) so I installed a newer (1914) carb.
(I'm having to machine a replacemen Needle for the 1912 carb. {ewwwww} šŸ˜µ
But, I'll eventually figure it out as we want the 1912 carb back on the car.
PS: The original Carb is a Holley..

Ride safe, Ted
Click to expand...
What was failure Ted? Was hoping to try "dopin" a problem lawn mower float bowl that corrodes seasonally.
Regards, Mercer Lee
 
Hello Mercer!
The airplane dope seemed to work fine.

One problem was the seat needle was worn out, so I reverse engineered 2 that I had, (prayed I had the lengths and angles right) and machined one.
I think that is working now, but not quite confident that I have the float level right..

The biggest problem was the car was very hard starting with the 1912 carburetor.
,,, On a Model T, you set the mixture screw before starting and adjust as you drive.
,,, I couldn't find the correct mixture adjustment, (and I was running out of time for a rally), so I moved to the other carburetor and eventually got it running right.

NOTE: I discovered that you can buy a {Chinese} lawnmower carb on Ebay for about $15.
So, I've bought/installed 2 on my lawnmowers.
Both worked fine.

Ride safe, Ted
 
Last edited:
I'm so use to the auto petcock now that I would definately forget to turn it off....but I do have overflows .
 
You must log in or register to reply here.
Top