Gents: I put this together for the hondatwins.net board and thought it might be found useful here as well; any comment or criticism certainly welcome.
So I noticed that my RH carb was not holding gasoline; pulled the float and it was about a third-full of gas and had three breaks in the solder that hold the float halves together, and hairline cracks from those breaks:
After pricing out NOS floats (!) and checking on the time it would take to get them to my house, I decided to try my hand at soldering them back together. I got some advice from the gang here.
Step one was to empty the float of gas, and confirm the location of the breaks in the float. I heated some water to a slow boil, just deeper than the float, and got a little cup of water to drip gasoline into (this helps keep your house from smelling like gas, which will in turn reduce the odds that you will need to sleep beneath your Honda.)
I dipped the float in the hot water for a couple of seconds, which causes the float to try to expel what it's filled with - you'll see bubbles where there are fissures or holes.
Each time I did this, I then held the float over the small cup of water until gas stopped coming out and the float cooled. This you will do over and over until the float is empty (took me about ten minutes or so.)
On the side of the float there is often a marking to tell you how much it is supposed to weigh - for the CB450 floats it is 6.7g. As it happens, my cooking scale works in 2g increments so it was well suited to my soldering skills! I just had to keep the finished product to under 8g.
Solder likes clean, rough surfaces, and not varnish. Clean that float!
Then gathered my tools for the next step: a soldering iron (not a soldering gun, will get too hot and destroy the float). Ideally you want a gun with a flatter tip than this so that you can better tin the solder to the brass. For my skill level it wouldn't have made much difference unless it were a magic wand at the end of the iron.
Oh, yeah, tools. So you'll need a soldering iron, flux, and good lead solder (not electrical solder, which has no lead and will not stick to the brass well.)
Your float was initally assembled by soldering the two halves together, with this little hole open, and then the hole was soldered shut. You'll need to open the hole back up - I was not successful in 'de-soldering' the hole, so took it to the drill press with a tiny bit at slow speed and opened it up. Careful not to tear the brass, it's quite thin.
Much better.
Now solder that float! First a thin layer of paste flux, then try to tin the solder to the brass float - then spread your solder as thin as you can while closing the cracks. If you are better at this than I am it will look much better than this. If you are worse please send some pictures so I will feel better about myself.
As I am aware of my limitations vis a vis soldering irons, I thought it best to make sure that I had, in fact, sealed the holes that caused this mess - but I didn't want to close the expansion hole and have to drill it out again. So I taped over the hole and went back to my pot of slowly boiling water (I mean, I turned the water back on. You remembered to turn this off before, right? If not, your house is probably on fire. Sorry I didn't mention it earlier.)
After you've confirmed that the float is holding air and no longer leaks, and has cooled from your repair of the cracks, seal the expansion hole with solder as quickly and neatly as possible.
So I noticed that my RH carb was not holding gasoline; pulled the float and it was about a third-full of gas and had three breaks in the solder that hold the float halves together, and hairline cracks from those breaks:
After pricing out NOS floats (!) and checking on the time it would take to get them to my house, I decided to try my hand at soldering them back together. I got some advice from the gang here.
Step one was to empty the float of gas, and confirm the location of the breaks in the float. I heated some water to a slow boil, just deeper than the float, and got a little cup of water to drip gasoline into (this helps keep your house from smelling like gas, which will in turn reduce the odds that you will need to sleep beneath your Honda.)
I dipped the float in the hot water for a couple of seconds, which causes the float to try to expel what it's filled with - you'll see bubbles where there are fissures or holes.
Each time I did this, I then held the float over the small cup of water until gas stopped coming out and the float cooled. This you will do over and over until the float is empty (took me about ten minutes or so.)
On the side of the float there is often a marking to tell you how much it is supposed to weigh - for the CB450 floats it is 6.7g. As it happens, my cooking scale works in 2g increments so it was well suited to my soldering skills! I just had to keep the finished product to under 8g.
Solder likes clean, rough surfaces, and not varnish. Clean that float!
Then gathered my tools for the next step: a soldering iron (not a soldering gun, will get too hot and destroy the float). Ideally you want a gun with a flatter tip than this so that you can better tin the solder to the brass. For my skill level it wouldn't have made much difference unless it were a magic wand at the end of the iron.
Oh, yeah, tools. So you'll need a soldering iron, flux, and good lead solder (not electrical solder, which has no lead and will not stick to the brass well.)
Your float was initally assembled by soldering the two halves together, with this little hole open, and then the hole was soldered shut. You'll need to open the hole back up - I was not successful in 'de-soldering' the hole, so took it to the drill press with a tiny bit at slow speed and opened it up. Careful not to tear the brass, it's quite thin.
Much better.
Now solder that float! First a thin layer of paste flux, then try to tin the solder to the brass float - then spread your solder as thin as you can while closing the cracks. If you are better at this than I am it will look much better than this. If you are worse please send some pictures so I will feel better about myself.
As I am aware of my limitations vis a vis soldering irons, I thought it best to make sure that I had, in fact, sealed the holes that caused this mess - but I didn't want to close the expansion hole and have to drill it out again. So I taped over the hole and went back to my pot of slowly boiling water (I mean, I turned the water back on. You remembered to turn this off before, right? If not, your house is probably on fire. Sorry I didn't mention it earlier.)
After you've confirmed that the float is holding air and no longer leaks, and has cooled from your repair of the cracks, seal the expansion hole with solder as quickly and neatly as possible.
