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Discussion Starter #1
I found out I had a leaky float after getting myCB350 carbs back from sonic cleaning. I was able to solder the leaks using this method...maybe one of you can use this info (see brass float paragraph).:
http://www.thecarburetorshop.com/Troubleshooting.htm

You can buy a new float for under $30, but I like to try home remedies before I drop cash...either way, if it works or not, I've learned something. Besides, it was kind of nice to feel like MacGyver/MacGruber.

Now, the drawback...it does change the buoyancy of the float...the less solder you can use to make the repair the better. In my case, it wasn't much. I was repairing pinholes that were barely visible. (A sharpy is great for marking the leaky spots as you find them)

A change in buoyancy has the effect of changing how much pressure the float can exert on the needle valve. So you can't rely on the "dry" float level check after making a repair. I had one good, original float that I set to spec w/out gas, then used that carb as a reference point for the next step. I did a float level adjustment on my work bench using a small piece of clear tubing with a plastic tip like the kind that come in a brake bleeder kits. Remove the bowl drain screw, wedge/screw the plastic tip in to the drain hole so that you have a tube hooked up to the drain hole. Set the carb up in a padded bench vice (carefull! not too tight) at about 10 degrees forward tilt. hold your tubing up higher than the top of the carb. Pour some fuel in the normal fuel line to fill the bowl (i used a tiny funnel as well). tap on the bowl with a screwdriver handle to make sure the needle valve is set. Now hold the tube (the one hooked up to the drain) against the side of the float and mark the fuel level with a pencil on the side of the float bowl. Do the same for both carbs and compare. Hopefully you didn't have to repair both floats...I had one good one to match against the repaired one. If the levels are off, adjust your float tangs and repeat. Heat and serve...your family will love it! Actually, skip that last part. Uh, remember, no smoking, no sparks and no heat...this is gasoline you're indeed playing with, brothers and sisters so think about where you're working. I've heard that cell phones can cause sparks. But that could be total BS. I'd hate to be the mythbuster, though.
 

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Discussion Starter #2
I came across a thread about setting the float bowls...that recommends holding the carbs level. That is probably the right way. 10 degree tilt that I used was something I read in a manual... either haynes or honda manual.
 

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I can vouch for my own methods...the tree-fiddy is rollin' smooth. Seems like the float levels are still on and not a drip from the overflow tubes. If anything comes up, I'll post an update. But for now I'd say try it, you'll like it. And best of all it is a free fix. At least if you own basic tools...
 

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All floats for a given carb model should be the same weight. Using a cheap balance scale (accurate weights are where the cost is - you don't need them) you can check the weight of the repaired float against the one from the other carb and file small amounts of solder/metal off the other float until they match. you should probably try to take metal off near the area that you soldered. Alternately, after draining the float, equalize the balance with counterweights. Leave them on the pan, solder the float, and file it down 'til it equalizes the balance again. Printed circuit board soldering irons are nice for the float repair task - they apply heat in a very small area, allowing you to do a repair with very little solder.
 

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Why is it necessary for the floats to be the same weight? As long as each float opens and closes the needle at the correct point when necessary, what difference does it matter how much they weigh?

Are you saying that a slightly heavier float will displace more fuel when it's at rest thereby changing the necessary installed height?
 

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I believe that is exactly what they are saying Mike, but I've repaired many floats and simply reused them at original height specs... Never weighed a float in my life.....Never had a problem...But I never used more solder than was necessary...
I can see how a large amount of solder might require a height change, but it would take a LOT of soldering to require even a minimal adjustment...( displacement being an equivalent weight of fuel to the additional weight of the solder , divided by the surface area of the submerged "skin" of the float).. If I had a float with that many leaks, I'd just replace it......
This could just be an "urban legend" type scenario.....
 

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Discussion Starter #7
The float changes density...the float volume isn't changing, just the added mass of the solder.
Density = mass/volume. Density is directly related to buoyancy...the more buoyant (lighter) the float is, the more pressure it will exert on the needle valve. So the denser, repaired float exerts less pressure, therefore it needs to be set higher (as in upside down, dry setting). In my case I set the float heights the same, then checked with fuel. I had to go back and readjust the repaired float, because the fuel level was too high. Granted, I was using a $3 soldering iron and this was my first ever try at this, so I probably used more solder than a more experienced person with better equipment.
I didn't mess around with a scale, though that would work too. I just figured I'd use fuel and make a "real time" adjustment...seems to have worked well. I double checked the fuel levels last weekend (was having unrelated carb issues) and it is still equal for the two carbs.
 

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I always set my float height the wet method, with the carbs on the bike (I want to make a stand but haven't gotten around to it). The dry measurement will get it in the ballpark, then use wet to fine tune it and get it spot on.

I equate it to carb sync'ing. Bench sync will get it in the right area, but not until you do a true vacuum sync will it be perfect.
 

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Discussion Starter #9
I don't know that you'd need to make a stand if you have a bench vise. I padded the jaws with cardboard and VERY lightly clamped it in place. Just enough that it was steady and secure, but not enough to damage the fragile carb bodies. Used a protractor and level to make sure the angle of the carbs were right when held in the vise, but that's probably being unneccessarily anal retentive about things. I tested the levels with fuel that way, then a couple weeks later on the bike to satisfy my curiosity.
 
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