1976 KZ400 stripped bowl screws

Hey guys. Well after cleaning out our huge ass garage we decided to move all our bikes in and start getting them all running. My beloved KZ1000 will be the next thread im sure after the my dads KZ400 cafe is finished. Anyways my current issue is a leaky carb that goes to cylinder 1 (on the left side if your sitting on the bike). When my dad first got the bike we had lots of carb problems so they were taken apart and put back together a number of times. After doing all the work and getting them all clean and taken care of, 3 of the bowl screws stripped. 2 on cylinder 1's carb on the intake side of the rack and 1 on cylinder 2's carb on the intake side of the rack. havent really messed with the bike for so long so it never got fixed. Whats the best way to take care of this problem? By stripped i mean the threads are gone in the carb body and the screws just keep turning basically. i was thinking maybe a more course threaded screw but im not sure.

Thanks guys,
KT

Also, this bike is running a 2 into 1 exhaust with a vance and hines muffler.. Also no airbox just pods. I think its got stock jetting too.

Do you have a picture of the float bowls?

This is the same kind of bowl. I found this pic on google:D camera aint charged at the moment. They're Keihin carbs.

I got rid of that kz400 i had a while back and a bunch of spare parts,no float bowls like those laying around.
Are the threads completely gone,could you use a couple wraps of teflon tape to tighten things up?

Thats why i never use the drain screws on bottem of any carbs unless i have to check float levels,i just pull the bowls off when i need to drain them

Actually the threads for the screws that hold the bowls to the carb bodies are gone thats what i was thinking was maybe plumber's tape and some new screws since i lost the others. good news though, even with leaky bowls that monster runs awesome:) fired it up just a little while ago for the first time in 2 years. Had a bad spark plug on cylinder 2 the whole time we owned it ahh well, you live you learn. Popped a new plug in and it started first kick running off my KZ1000 battery. needed new fuel lines too. I thought that all the leakiness was coming from the bowls. about 80% of the leakage was bad fuel lines. A few snips on a reel of fuel line i got and it was set dood.

The short answer is, maybe. I am assuming the screws just turn but won't come out, right? Common with steel screws into aluminum. What happens is, the threads get filled with the aluminum and they kind of lock in but won't bite. So, first thing is to get them out. Grab the screw had with a small pair of vice grips. Turn counter-clockwise (lefty-lucy) while pulling on the screw and you might be able to get them to bite enough to back out.

You can re-tap the holes (I explain that below) or likewise drill and tap the holes for a helicoil or recoil kit which replaces the threads, but with a through-hole like that and not much material on the carb body itself, I'd go with re-tapping the holes first. Plus, recoil kits are expensive but available from places like Fastenall and others.

So, here's how you can do the re-tapping gig:

Once you get them out, clean the screws off and determine what size they are, like an M5x1.0 or M6, etc. The M5 is the size, the 1.0 is the thread pitch. 1.0 is a fine thread where 1.5 is course. Those are most likely fine thread. Go to any Ace Hardware and they have all sorts of Metric Phillips head screws that size. I just bought a bunch. You'll need the next size up. Lets say the original was M5, so get a few M6x 1.0 or 1.5, whatever the current pitch you have is. You can match up the old screw with new ones of the same size to see, or use their screw sizing tool.

Here's the tricky part - once you determine the next size up screw, you'll have to go look up the tap drill size for that screw. Make sure you know the thread pitch whether it's fine or course. Get that drill if you don't have it. Now, see if that drill with hand fit through the stripped hole. If it doesn't, you're good. If not, the hole is too big for even the next screw size up and you probably won't have enough material to cut threads.

So if the hole is the exact same size as the tap drill and it fits snugly through, that's probably ok. Now, get a tap for that thread size and pitch. Run the tap drill through the hole if needed and re-tap the threads.

Finally, you'll have to figure the drill size also for the clearance holes on the float bowl itself. There should be enough material on the float bowls to cut those clearance holes a bit bigger. Just be careful the drill doesn't grab and screw up the hole. You'll probably only have to drill out a little bit.

Hope this helps. If you want me to work on the carbs for you, I have a lot of machine tool schooling and experience from working in machine shops (years ago) and doing it on the side since then. Ship the stripped down carbs to me (no floats, at least) with the bowls and I'll give you a price once I see them.

Forget the plumbers tape, teflon tape, etc. That's for an emergency only. The only way to do this right is to re-tap the threads, if possible.

I'm in Bradenton, FL.

I know that its probably not the right way to do this but i found that the carb quit leaking for some reason filled the tank up and set it to on and the seam all around the bowl was dry. i think ill just have it together but missing 2 screws since my dad's gonna flip the bike anyways. I guess this thread was kind of a false alarm on my part. Thanks for the reply and going through how to re-tapp the holes. i saved it in a txt document

ok now a new problem has presented itself.. I know i should know whats wrong but i dont know what the hells happening i figured out most of the wiring in the headlight bucket a few hours ago and figured i would fire it up to see what was what. So the good news is that i have a good working set of gauges all mounted and functional. so i ran it for maybe like 5 seconds and then i shut it off. went out and put some wood in the wheel barrel to stack in the garage and when i came back, there was a big puddle of gas on the floor. I run over and look and its coming out of the nipple right on the bottom of the float bowl. tried to shut the gas off since its either "on", "Reserve", or "off" on the petcock. the gas just kept on coming out. then i stuck a hose on the nipple and put a bolt in the end of it and gas started coming out of the little bowl breather nipple on the side of the carb so then i just stuck a rag under it and pulled the fuel line off the carb and stuck a bolt in the end of that. Is the needle not seating properly or are my float levels way off? the bike was on its side stand leaning towards cylinder 1 when this all happened. The gas was coming out of cylinder 1's carb. Last year the kickstand mount broke off and i think it was re-welded on too far up on the side of the frame so the bike kinda leans hard on its kickstand.. would that be an issue?

Could be both your carb needle and the petcock itself. Petcocks are notorious for leaking through, doesn't matter what the make or model is. If you haven't rebuilt the petcock, get yourself a rebuild kit and do that first. But your #1 carb needle could be bad, could also be an improper adjustment of the float level, etc. But I do not think it's the angle in which the bike leans. At some point, of course, if the bike leans too far, fuel will spill out the vents. That's like laying sideways, though. Something like that. No, what you have going on in my opinion has nothing to do with the kickstand.

It would help if I knew what has and what has not been rebuilt on the fuel system, have you done the carbs over and/or the petcock yet?

That's not a vacuum actuated petcock if it has a true "off" position, I was thinking it was a vacuum actuated one... however, that doesn't mean it isn't leaking through, still...