I had a spare set of dirty old carbs that came with one of the bikes. When I opened them up for inspection I found 3 broken float posts. So basically they are junk. Since I felt that I had nothing to lose, this seemed like a good opportunity for me to experiment with float post repairs.
I’ve read about the drill and tap bolt method but was always afraid to try it. The idea is to cut off the broken post, drill down through it and tap it. Then screw in a bolt and cut off the head to make a new post. Looks and sounds easy enough, but I am certainly no machinist. While walking through Home Depot, searching for an appropriate bolt, I stumbled across a package of shelf supports that looked like they might work. 12 in a pack for $1.87 was worth a try!
First I decided to try cutting threads on the shelf support. I tried a couple of different die sizes and then settled on the 10-32 die, just because it looked like it would fit.
Next I cut off the broken float post to make a smooth surface, then center punched it, drilled and tapped it. That went surprisingly well and rather easy also, because of the soft aluminum body. I used a 9/64“ drill bit. I think a 1/8″ bit might be a better choice, but again I am no machinist, I just chose that size because it looked like it would work. And it did!
It took me a couple of attempts to get the thread depth correct so that the new post wasn’t too tall or too short. I used a hand drill on the first 2 that I drilled. On the 3rd post, I used a drill press which was probably a better choice, but the hand drill worked fine.
Drilling the float pin hole in the new post was a little bit difficult though, because it has to be centered pretty precisely for the float pin to line up straight and be level.
And then a little “seal all” on the threads just for good measure and you have a successful and not a bad looking float post repair.
The 2 posts on the left and the one on the far right are originals. The other 3 are my homemade replacements.