Carb problems (float bowl, jets, etc) please help

I have a 1978 KZ1000 A2 with 28k that had been sitting in a basement for 5 years (ran when it was put away), didnt run when I bought it. The pic is of it after I cleaned it the day I got it.

The overflow tube in one carb bowl has a crack going down it causing it to leak gas. I tried to solder it but it wouldnt take, and the gas ate through JB weld within 30 minutes. I cant find anywhere that sells the float bowl. Does anyone make them or do I have to search around for a used one? Are there any other makes/models that used the same carb with the same float bowl? Or does anyone have a spare one they would be willing to sell?

If I cant just the float bowl for a reasonable price, I am going to buy some used carbs off ebay. Is there any other model of carbs that would be worth upgrading to such as the VM28SS?

I rebuilt the stock carbs with a kit containing for each carb:
(1) Float Bowl Gasket
(1) Top Cover Gasket
(1) Float Valve Assembly 2.0
(1) Main Jet (105)
(1) Main Jet (107.5)
(1) Pilot Jet(15)
(1) Pilot Jet (17.5)
(1) Air screw , Spring and O-Rings
I set the throttle valve at 0.7mm and the float level using the clear tube test at 2mm below the top of the bowl, and the air screws are backed out 1 1/8 turns.

I used the 105 main jet and 15 pilot jet because that was what was in there stock. Is it worth it to try the bigger jets, or just just a pain in the ass to tune afterwards?

The bike runs pretty good now after I rebuild the carbs, but I have nothing to compare it to because I never saw the bike run before now. It still blows white smoke above 5000rpm and studders and kicks and stalls trying to idle at 1000rpm even after I played with the air screws.

If anyone has ANY information PLEASE post it I would really appreciate any help.

Thanks
Matt

Shrink-tubing might seal the cracked overflow tube if possible to cover the entire crack.

Uncertain why solder didn't stick (wrong solder, faulty prep?) or why the JB Weld dissolved (was it fresh, properly mixed and allowed to fully dry?), as others have reported success with these remedies.

In any event, could attempt sealing the crack with Permatex fuel-proof sealer.

Or remove the tube and seal the float bowl exit with Permatex fuel-proof sealer, and simply run the carb without an overflow (ala 29 smoothies). Requires properly operating float, and needle/seat closure, and fuel level, and turning off petcock when engine's not running (all the special attention items required by those of us running 29's, which don't have a float bowl overflow system).

Good Luck!

What about all the varnish that was in the tank from the 5 year old stale gas, did you clean that out? if you dont it will run right back in and screw up the carbs.

When I tried to solder it, I cleaned it with Simple Green first, then soap and water. Then I layed down some flux and the solder still would not flow into the crack. I may have not mixed the JB weld enough because after 30 hours of dry time it was still sorta tacky and I could make a dent with my fingernail.
The gas tank was drained before it was stored and the carbs were also drained so there was no gunk in them when I tore them apart.
Ill take the bowl off again and try to solder or JB weld it again tomorrow, thanks for the replys keep em comin!

I used JB weld for this same job myself and it should work. As long as the surface is clean and dry and the stuff has been mixed well it should be rock hard and fully cured at 24 hours.

Another fix I used was that I took the carb bowl to a hobby shop where they sell small brass tubing and tried the various diameter tubes on for size until I found a length which would just slip over the overflow tube. I cut the new tube a smidgen shorter than my overfow and slipped it over. Gave the surfaces a quick wipe with fine sand paper and soldered top and bottom making sure not to plug the top of the overflow. A bit finer job than if I was plumbing It has worked well this past 5 years. Probably a more permanent solution than JB weld. Looks better. Only thing to watch out for it to make sure the JB Weld or the solder does not interfere with the operation of the float.

Worth a try and cheaper than looking for new bowls.

Good luck