TOPIC:

A full rebuild for sure.  Just be careful to not loose those small balls and springs on the choke rod.

Fully break down the carbs, and soak all the bodies and jets.  Hold the pilot jets up to a light, and make sure the tiny orifice is open before installing them.  Shoot carb cleaner through all passages and make sure it's coming out where it should.  In particular, pay attention to the pilot circuit, including the pilot screw passages.

During reassembly, use a drop of oil or silicone grease on the new O-rings, before install.  

Good luck

I got carb number one taken apart (mostly). I'm going to the hardware store to get a smaller screwdriver, but I'm stuck on removing the float valve. In the manual, it just says to pull out, but it's giving me a lot of resistance. I've soaked the thing in WD40, and tried using needle nose pliers to get it out, but I'm wary of forcing and ruining the valve. The main needle jet is also not coming out smoothly. I threaded the pilot jet screw back in and gave it a few taps with the back of the screwdriver as outlined in the rebuild tutorial. Didn't pop out like I expected. I soaked everything in WD40 while I go to the store, hoping it will free up a little bit. I linked a few pictures of what I'm looking at right now. Diaphragm of the first carb seemed alright, albeit a little twisted. 

IMG_1275.HEIC
IMG_1276.HEIC
IMG_1277.HEIC
IMG_1278.HEIC
IMG_1279.HEIC
IMG_1280.HEIC

 

Sorry to say, but that float valve in the photo is damaged beyond hope.  You will need a new one.  You may just want to replace them all.

I use heat on the carb body, around the seat.  A torch, moving, fast.  And some PB Blaster, or similar.  The reason the seat is hard to remove is because the O-ring has petrified.  Also, the green grunge around the emulsion tubes is indicative of really dirty carbs.  The internal passages in the bodies have that same crap in them.  

Edit: I buy a lot of these kits, for the float valve and bowl gaskets.  They are cheaper than buying these parts separate...

www.siriusconinc.com/products/detail/601

Got it. I already have the float gaskets, so does it make sense to buy the float valves separately? Is that kit specific to my carbs? I've gotten almost everything removed now -soaking in WD40 seemed to free it up.

Currently working on separating the carbs. Having a little trouble getting the choke lever loose - the repair manual just says to remove the circlips, but I'm unsure of the technique. I'll keep working and most likely will figure it out eventually. I've got a heat gun that I've been using, which heats everything up pretty well and helps loosen the stubborn bolts up. 

My other current issue is the pilot jet. I've gotten it loose with a well-fitting screwdriver, but I can't get it out of the 'tunnel' it's recessed into. I've tried turning the carb upside down and shaking - as well as some light prying with the screwdriver. Again, trying to be gentle here so unsure of how to remove the pilot jet. (Top most passage in first attached image). 

I also attached a picture of everything I've pulled out of the carburetor so far (float valve, main jet, pilot screw + spring). Is any of it worth saving? Or is it all shot beyond repair? What should I be looking for to determine levels of damage? If carb 1 is this bad, I'm assuming the rest will be, but I am going to wait until everything is apart before I order more parts. 

Thanks for the continued help, I'm going to break for lunch soon and will update when I get the carburetors separated. 

IMG_1280.HEIC
IMG_1281.HEIC

There is a C clip for each of the choke lifters, that needs to be removed, before the shaft can be pulled out.  Another reminder about those springs and balls...

Other than maybe the float valves, those parts are reusable.  I use a stainless steel brush to clean the jets.  Soak them in carb dip over night first, though.  If you can save the float valves, use a Q-tip dipped in polishing compound and polish the inside bore.  And always keep the float valve seat and needle together as a set.

If you buy carb kits instead, get Keyster brand.  Those Suzuki kits I listed have the same float valves as your KZ bike, and the gasket is the same too.  I realize you don't need the gasket right now, but save them for the future.  Or, buy KZ carb kits.  They will be more expensive, though.

Well, I've been at it all day - but I'm admitting defeat - for now at least. 

The 8 screws that hold the lower mounting bar for the carburetors seemed to be seized in place. Whoever worked on this last seemed to have a similar problem - all of the screws have some evidence of mild stripping. I've been struggling with them for the last 5 or so hours, to no avail. No matter what combination of heat and PB Blaster I throw at it, they won't budge. I considered just soaking the carburetors as one unit, but considering the rubber fuel lines that run between them and that I can't fully remove the choke plungers with the carbs still together, I decided to hold off. After more or less stripping the head off the first screw I figured I was doing more harm than good and am going to let it rest until next weekend. I'm going to an SCCA race with the best mechanic I know and we'll take a crack at it then. I think this is a blow torch or circular saw problem.

My first thought is to cut a slot in the top of the screws and use a big blade screwdriver to crank them out. I'll note any ideas that y'all have, I am going to let the screws soak in PB Blaster and take another crack at it next weekend. I'm a little disheartened, but once I get this bracket off I know it will be pretty straightforward. I've got the choke removed and the springs and balls in a labeled Ziploc. Same goes for everything else I've taken off... I had a feeling this wouldn't get done today, so I took extra care to make sure I would be able to put it all back together a week or so from now. 

Thanks for y'alls help. Pics linked below. 

IMG_1283.HEIC
IMG_1286.HEIC
IMG_1287.HEIC

Part of the problem is that somebody before you used a Phillips screwdriver on them. They are actually JIS cross head screws. What you need is one of these. Heck, get both.

www.z1enterprises.com/yamaha-xs650-impac...bit-set-in-case.html


www.z1enterprises.com/jis-screwdrivers-s...three-144-244-4.html


I bet the impact driver will get all of them out.

I’ve got JIS screwdrivers - plenty of “grip” (is that the right term? Idk) on the screw. My hands will slip off the screwdriver handle before it goes anywhere. I don’t have an impact, but I’ll see if I can find a used one somewhere/borrow a friends.

It is very clear to me that someone before me tried to get all of them off with a Phillips - which is why I’m wary to try to force them off - even with the right driver. They are borderline as it is, I fear I’ll only make it worse as of right now. 

Thanks for the help and quick responses, I’ll update when I’ve got something new. 

Unfortunately, in this case penetrant may not even reach the threads, but try it anyway.  The last resort would be the needle nose vise grip pliers and some heat, but you'd be surprised at what can be loosened with an impact driver.  17 dollars is a good price for a quality tool that will probably last a lifetime, and you'll use it more often than you think. (if the carb screws are butchered, there will be plenty more ).  I've had my impact driver since the late 70's and have used it often ever since.

Scotty

As mentioned earlier in this thread, a couple of Vessel Impacta screwdrivers will get those screws out easily (or at least they would have, before the heads were stripped).  I can't imagine working on carbs without them...

They are impact drivers.  Engage cross point with screw, and hit the end with a hammer...

www.amazon.com/Vessel-Megadora-Impacta-P...river/dp/B003BI8HHQ/
www.amazon.com/Vessel-125943-P3x150-Impa...river/dp/B003BGTTSE/

Now that those cross point heads are damaged, a pair of vice grips can be used to grab them and break them loose.  

Apologies to Nessism - I didn't know those Vessel Impacta drivers were impacts. I cheaped out on a full set of JIS screwdrivers from a different brand for like 10 bucks less. Learned that lesson the hard way. 

The only screw that is beyond saving is on carb number one, the rest look torn up in the picture, but will still grip a screwdriver. I'll order those Impacta screwdrivers and give it another go. 

If the impact drivers don't work get out the left handed drill bits. Most of the time they unscrew just before the head pops off. I had to drill out 29 screws on the 78' KL 250 and every one of them came out before losing their heads.