TOPIC:

Got it, thank you. 
Agreed there's no way I would be able to clean/rebuild a set of carbs in a couple of hours, I was just trying to imply that a pro could probably do it in 3-4, which means it will probably take me 10-12. I've got a set of JIS screwdrivers and a can of Berryman's on the way. 

I might make the drive to the hometown and get my old man's help with this, seems like it might be worth it. 

Is there a way to check if my float valves have failed without taking the carbs apart/out? If I need a new set, I'd like to order them now before taking everything apart. 

As far as I can tell this is the float bowl gasket I need (x4) 
www.z1enterprises.com/yamaha-xs650-float...0%20LTD%20SHAFT/1985

I found several 'rebuild kits' in my research, but I'm going to steer clear as you suggested. (Especially the E-bay ones lol). 


Thanks again for your help.

Those Z1 float bowl gaskets are correct.

Regarding the float valves, you have to open the float bowls, remove the float, and inspect the tip of the needle.  Chances are, you will be okay, unless the bike has tons of miles.

And please be sure to follow the tutorial I linked.  Details like how to remove the float pin without damaging the float post are critical to your success.

Other key details, are making sure the choke passages are open, both in the float bowl, which often clog, and through the carb body.  

Hi all, 

I've got two updates on the bike. 

1: On going to inspect the spark plugs I noticed one of the spark plug wire terminals wasn't fully attached to the plug. I feel dumb for not checking this earlier, as it likely could be contributing to at least some of the issues I've been experiencing. 
2: On going to test start the bike after my discovery, it wouldn't crank. The starter doesn't click or turn over or anything. There is a faint, occasional ticking noise coming from the front left handlebar controls (where the turn signal light controls are located) when turning the key on. Since I've owned the bike, the key has needed to be in a very specific position to start the bike - I turn it on until the lights come on and the tachometer needle bounces slightly. Then I can crank the bike as normal. The battery is charged, as I keep it on a tender when I'm not trying to start the thing. Any ideas of what could cause this no-crank condition? I'm assuming a safety switch isn't being flipped (clutch kickstand etc.) or there's a shorted fuse somewhere, but I'm not sure how to track those things down on this bike. Please advise. 

The materials I need for the carb rebuild are on the way. I doubt the spark plug wire terminal is a complete fix, but it would explain the bike running on less than 4 cylinders and the unhappy idling/starting. When the bike would run for longer than 30 odd seconds, it would backfire and run rough - which to me signals a misfire of some sort. Even if the spark plug wire fixes most of my problems, I will likely tear down the carbs in the near future as I've got the parts on the way and the bike is likely due for it (26k miles). 

One last thing I wanted to mention - Nothing changed on the bike since I started it last, but I did forget to turn the kill switch off while it was hooked up to the charger. Could this have shorted something out? The starter fuse doesn't look like any fuse I've seen before so I' unsure of how to 'check' to see if it's good. I've been trying to start it off the kickstand, in neutral, with the clutch held in. Lights and turn signals all work as before. 

If you look at my fault finding guide ( the link is in my signature) towards the back there is a process flow for checking the starter circuit ( the starter isn't fused by the way)

Here's a funny one for y'all. 

Went out in my backyard to try to start the bike again today. Same as before, with occasional clicking from the left handlebar, but no start. Then, for whatever reason, I flicked on the left blinker and tried to start the bike. The starter kicked right in and the bike stuttered briefly to life and died. That gave me a chuckle and deepened my confusion with electrical systems. 

After a few starts, I've more or less decided I'm in the same boat as before. The bike will still turn over and start up with the right combination of dumping fuel at it, but removing the choke or any additional throttle will cause the motor to sputter out.

There is one new symptom:
When starting with the choke fully engaged, the bike will crank over and settle into a (relatively) smooth idle at ~2,000 RPM. Once it warms up a little bit, the motor will shoot up to 4,000-5,000 RPM completely on its own. This panics me a little, as I know revving up a cold motor is never good for the bearings, so I try to push the choke in some, but doing so will just cause the motor to putter out and die. 

I don't think any of this changes the diagnosis or treatment plan (so to speak), but I wanted to update everyone in case there was something that I missed that is jumping out at y'all. I'm still planning to rebuild the carbs this weekend and will be borrowing a multimeter from a friend and chasing electrical faults while the carbs soak. 

Hi all, 

Replying mostly to keep track of my progress at this point, but I would love any advice or pointers if they come to ya. I pulled the carbs off the bike today, I'm going to start rebuilding them tomorrow morning. I've got the O-rings, float gasket seals, and a can of carb dip all ready to go (huge thank you to Nessism). I printed the recommended guide, and marked where it differs from my carburetors. After pulling the carbs, I gave them a good look over, and something seemed off with carb number 1 (assuming left to right numbering). It looked like that valve (?) was installed crooked. I linked the pictures here, let me know if that jumps out to y'all. Carburetors are new to me, so I'm not quite sure what I'm looking at here. Any help/pointers are appreciated as always. 
IMG_1271.HEIC
IMG_1272.HEIC

I'll continue updating with my progress and pictures tomorrow, and whatever questions/roadblocks I hit along the way. 
Cheers!

Wow. Kawasaki calls that a diaphragm valve. I think most folks here refer to it as a piston. At any rate, it ain’t sposed to look like that   My amateur guesses are, the diaphragm was replaced and not properly indexed, or the diaphragm is ripped and allowed the piston to get misaligned, or a midget zombie magician has cast a spell on that carburetor.
That does not explain the electrical problems, but that would surely prevent the engine from idling or running properly since here is no way for that carburetor to properly meter fuel.

The diaphragm is installed wrong.

The diaphragm has an indexing tab, that's supposed to mate up with a similar depression in the carb body.  Sometimes, people don't understand the nuance of this, and they slam in the diaphragm out of position.  

My guess, is that when you remove the carb top, you will find the diaphragm tab smashed and possibly cut.  Hopefully, though, the diaphragm isn't cut though, and you can reposition the slide they way it should be, and put the carb top on properly.  I've done just this many times before.  It's too bad that there are so many hacks out there, because sometimes they destroy parts they are trying to fix.

Yeah, I thought something seemed off haha. I'll start with the diaphragm and share some pictures when I get the chance. 

Is this likely to be the only issue? I think a full soak and 'rebuild' is still worth it as there could be other issues within the carbs and I already have them off and on the bench. 

I think it would be foolish to skip a full rebuild at this point. There is no telling what other surprises may be lurking inside, and skipping something might necessitate removing and disassembling them again.