Author Topic: How to fix a brass carb float that has fuel in 1 side ? (Read 15425 times)

grcamna2 · « **on:** November 09, 2011, 05:56:46 PM »

Can anyone please tell me how to successfully repair a brass carb float that has fuel inside of it on one side ?
Thanks

Johnie · « **Reply #1 on:** November 09, 2011, 06:02:43 PM »

Some guys have tried and I am not sure if they are successful. Once you solder it back up you will change the weight which could mess up the float height. Might be better off to buy a new one or find used and hope the used is OK when you get it.

grcamna2 · « **Reply #2 on:** November 09, 2011, 06:25:17 PM »

I notice a new one on Ebay...but I really want to fix this one.I think it's possible.

BobbyR · « **Reply #3 on:** November 09, 2011, 06:31:16 PM »

First you have to get the gas out of the float. Then clean the brass very well and solder up the crack. You can adjust the float so it will work well.

OK you have fixed that float for now, assuming they are all the same age you will probably have another start leaking. You can buy plastic replacements which will last and last.

05c50 · « **Reply #4 on:** November 09, 2011, 06:43:45 PM »

I have successfully repaired a couple floats that were no longer available. My first attempt turned into a little fire ball when I was unable to get all the gas out and the heat blew it up. My second attempt wasn't quite as exciting. I decided to drill a small hole in the float and allow all the gas to to evaporate. Then I soldered the crack and then soldered the vent hole The brass used on floats is very thin and requires a delicate touch to cleanly repair it without adding too much weight. If done correctly, the float will work like new and not cause any adjustment problems.

................Paul

grcamna2 · « **Reply #5 on:** November 09, 2011, 07:16:19 PM »

Thank You VERY MUCH fellow sohc4 Members...I needed to get those feedback posts !
Please keep 'em coming.

Raul CB750K1 · « **Reply #6 on:** November 09, 2011, 09:55:17 PM »

I'll tell you my experience.

In order for the solder to spread around the brass, the brass needs to be hot. If you just heat the area where the crack is, you will end up leaving a blob of solder, because it cools down very quickly and doesn't spread.

You can heat the whole float but chances are it will crumble and fall into pieces, as it is formed by soldering pieces together.

what I did after I left the blob was to heat it again an quickly wipe off the excess with a cloth. That will leave a thin film of solder.

In order to avoid me the hassle of assembling and reassembling if the fix didn't work, I put some gasoline on a jar and put the float in -made it to the bottom by adding weight-. Next day there was gas inside the float!

Don't ask me how did it get in. I had wasted enough time, and didn't want to waste any more or assemble everything just to have to disassemble again. Bought a new float, put everything back in, and got on with my life.....

Kept the old float just in case, maybe in 20 years I'm still alive, I still keep my bike, the float fails and Honda doesn't have floats for sale... :-)

BeSeeingYou · « **Reply #7 on:** November 09, 2011, 10:01:25 PM »

I have repaired a few this way with no problems. Sometimes they are so weak though that they soon spring another leak. I had a new float with a bad mounting tang so I un-soldered the floats and put them on a good tang that had bad floats. If you are really desperate you could do this leaving the weak side up. 35 watt gun worked fine.

HondaMan · « **Reply #8 on:** November 09, 2011, 10:38:30 PM »

I usually drill a tiny hole in the center of the float (on the flat side), then heat it up with a candle a little at a time. Sometimes I get a cool little firespout out the hole for a second or two. Don't let the brass get too hot, or it will melt the other solder. After the gas is gone, you can shine it up (gently) around the new hole with 400-600 grit sandpaper, steel wool, or just use acid solder paste. Then, a small soldering iron or a pinpoint propane/butane torch (like the tiny ones Radio Shack sells) and some SMALL, thin solder will seal the hole in seconds. Then, I take the same torch or iron to the most likely-looking leak spot and (after cleaning) heat it up and seal the area with a touch of the solder. Afterward, take some steel wool or fine sandpaper to the new solder and gently sand it away to a thin skin again, because you might not have the deft touch of the Japanese fingers who first made them.

grcamna2 · « **Reply #9 on:** November 10, 2011, 05:17:53 AM »

Thank you HondaMan,
I have already pushed the tip of a push pin into it & drained it(it was 1/3 full!)so I know the old stale fuel is gone from inside it.The float had no area that I could see that was leaking,I checked & checked... well... I wonder if I should try adding any solder to the very thin places it has around the circumference of the one tank... according to you,it is very important to NOT get too much solder on the float to weigh it down.The solder seems so thin in those areas...I think I will have a tough time trying to match my other original floats for weight. Will the amount of solder I apply make a BIG difference in the balance of my other carbs ? I may have to tin my 40 wt. pencil type iron and go around the whole circumference of the float...do you think I could do it as a first timer ? or would I be better to just order a new one ? will the new one have similar weight as the other original floats that I have as far as the amount of solder used in it's manufacture ?

Thanks

ekpent · « **Reply #10 on:** November 10, 2011, 08:38:00 AM »

Give this stuff a try,it really is gas resistant.Fixed a cracked emulsion tube holder with it once and a float for a Suzuki smoker . Says it works on floats in product description

http://www.totalmotorcycle.com/reviews/SealAllGlueReview.htm

stampederunner · « **Reply #11 on:** November 10, 2011, 10:27:16 AM »

Drop each float into boiling water and the pressure difference will create bubbles where your hole is. I had floats with no gas in them that still bubbled under boiling water. I soldered the holes then rubbed them down to a thin layer using fine emory cloth.

ekpent · « **Reply #12 on:** November 10, 2011, 12:06:55 PM »

Not knocking your method but seems like it would be hard to see the tiny bubbles in boiling water.

stampederunner · « **Reply #13 on:** November 10, 2011, 02:09:35 PM »

Guess I should have added a little more detail. I boiled the water inside and carried the pot of water outside to dunk the floats. The water stops bubbling almost as soon as you remove it from heat. Once you submerge the float the bubbles come streaming out and last for a while making it very easy to pinpoint even the smallest pinholes.

grcamna2 · « **Reply #14 on:** November 10, 2011, 02:27:16 PM »

to stampederunner,
I like your idea;please go into more detail about" boiling the water inside...etc.
I want to follow your method because it sounds the best so far.

stampederunner · « **Reply #15 on:** November 10, 2011, 02:42:24 PM »

I was just clarifying that the water wasn't bubling when I submerged the floats.

grcamna2 · « **Reply #16 on:** November 10, 2011, 04:18:51 PM »

Do mean to get the water boiled up well & then at that point remove the pot from the stove & submerge the float & if the float has a leak it will bubble in the very hot water.
I imagine the float getting hot like that expands the air in the float & it comes out at the point of the leak or leaks....? Is this what you are saying stampederunner ?

TommyT · « **Reply #17 on:** November 10, 2011, 04:32:18 PM »

dripmethod

FUSE

That should work for you. I have used this in the past on many things and it's amazing stuff.

grcamna2 · « **Reply #18 on:** November 10, 2011, 04:42:18 PM »

TommyT,
Have you used it before? is it aluminum? or epoxy? how is prep?
It looks like a great filler;what do you know about it ? I will need to use VERY little solder so that I won't weigh down my floats.
Thanks for the post Tommy

stampederunner · « **Reply #19 on:** November 10, 2011, 05:11:43 PM »

Quote from: grcamna2 on November 10, 2011, 04:18:51 PM

Do mean to get the water boiled up well & then at that point remove the pot from the stove & submerge the float & if the float has a leak it will bubble in the very hot water.
I imagine the float getting hot like that expands the air in the float & it comes out at the point of the leak or leaks....? Is this what you are saying stampederunner ?

Thats exactly what I'm saying. You need to pull it out of the water before it stops bubbling or water will get in.

grcamna2 · « **Reply #20 on:** November 10, 2011, 05:20:01 PM »

Thanks Stampederunner...that gets me a bit closer to fixing it successfully.

d9canada · « **Reply #21 on:** November 11, 2011, 04:18:22 PM »

I have not had to do this repair but a very detailed guide for rebuilding CB900C carbs recommends using JB Weld for floats, vent tubes and float bowls. Make sure the material is fully cured before using it. I was surprised to see that JB Weld is impervious to gas. This gives you an option that does not require an open flame.

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Author Topic: How to fix a brass carb float that has fuel in 1 side ? (Read 15425 times)