Sgt. Howard
Active Member
My first build has the NT carb, which is a fine carb except for the fact that the float has a leak and gets logged up with gas. I had tried drilling two holes to drain it off and then plugging the holes with toothpick ends- typically I get a week or so of running before that becomes an issue again. I have recently used PVC grey cement to seal the leaks, having given it 48 hrs to cure before putting it in the carb (based on the discovery that there are those who have built gas tanks out of PVC without any issues with dissolving), so I will report how well that works- so far, I am getting perfect performance.
Here are some thoughts on the issue-
The leak is likely where the two parts of the float join- there is a seam on the outside and on the inside diameters. By swabbing both with cement, I am likely to have covered the leak. I also covered the two holes I drilled... I drilled them into the top surface (the one closest to the seam) thinking that they would spend less time submerged in gas. Yea, but the get showered with gas when the bike is running... in the future, I would drill into the seam itself at 180 degrees apart. The outside of the float has no contact with the carb in operation, so friction is less likely to undo the seal... and the seam towards the top keeps it out of the gas.
A small pinhole in the seam will allow air and/or fuel mix to enter/exit the float with changes of pressure/temperature- if the seam is kept on the UPSIDE to begin with, this will lessen the odds of it happening.
Here are some thoughts on the issue-
The leak is likely where the two parts of the float join- there is a seam on the outside and on the inside diameters. By swabbing both with cement, I am likely to have covered the leak. I also covered the two holes I drilled... I drilled them into the top surface (the one closest to the seam) thinking that they would spend less time submerged in gas. Yea, but the get showered with gas when the bike is running... in the future, I would drill into the seam itself at 180 degrees apart. The outside of the float has no contact with the carb in operation, so friction is less likely to undo the seal... and the seam towards the top keeps it out of the gas.
A small pinhole in the seam will allow air and/or fuel mix to enter/exit the float with changes of pressure/temperature- if the seam is kept on the UPSIDE to begin with, this will lessen the odds of it happening.
