I've got my carbs back together with no problems except one. The choke pickup tube passage hole at the bottom in one of the float chambers is clogged. These are always stubborn to clear, but I simply can't get one flowing. I've used penetrating fluid, sonic bath several times now, air pressure, and a bristle brush wire, but haven't had any luck. It's the very last think keeping me from putting these carbs back on the bike tonight!
Can I drill the passage open wider to get it cleared without causing problems? It seems that all the passage does is supply the pickup tube with fuel for the choke circuit.
Suggestions?
I gave up and got new carb bodies! That's a hard passage to clear.
I got the passage cleared. I gave up on trying to unclog it, and drilled it open with a 3/32 bit. It punched thru some kind of obstruction and now flows fine. I definitely opened it up a little more than the other three. So I drilled all four chambers to balance them out. I hope I didn't create a problem with my choke circuit. I don't think it would, since all I'm doing is providing plenty of gas for the choke pickup pipe to circulate.
This is such a common problem on every carb I work on, that I wonder if I shouldn't just make this part of every carb rebuild. Even when I get the passages cleared, barely any fluid trickles thru on every chamber. If the choke circuit works fine on these carbs, I think I'll start doing this from now on. I'll use the next smallest drill bit though, I just used the smallest one I had on hand.
Good tip, thanks Karl!