New to me GS550 won't run without choke

[Isoparmesan]

Ah, thanks for pointing me to your restore. Should be a good resource for me. I think mine is starting from a better overall place, which is good to see. Previous owner owned and maintained it for 17 years, but only stopped riding it three years ago. Definitely going to get some Berryman's, do a full disassemble/soak, maybe another ultrasonic pass. I also ordered new O-rings for the carbs and boots.

The goal here is to get the bike running well enough so my wife can use it. Looks like I've got my work cut out for me.

[OldVet66]

You do, but once you do it, there is a whole lot of life left in these bikes. The last major work I did on my bike was about eight years ago, running fine.

[Isoparmesan]

Ok. I’ve begun the process of chem dipping the carbs. I can only fit one carb and all it’s screws/jets/bowls into the can at once.

I've just removed the first one, rinsed it with water, and dried with a combination of a hair dryer and some canned air. Everything looks much cleaner, but the main carb body has developed a chalky oxidation. Is this normal? And if not have I damaged anything? Do I need to remove this somehow before rebuilding everything?

it was in the can for a little under 24h

I’ve attached a photo with the clean carb body on the right, and a yet-to-be-dipped carb on the left.

[cowboyup3371]

It is normal and no you didn't damage anything

[Isoparmesan]

The oxidation will rub off with on my finger. I'm just wondering what the effects are of it coming off and flowing into the cylinder with the gas. The instructions for the chem dip mention treating low alloy metals with penetrating oil, but I also don't necessarily want that mixing with the gas.

I'm probably being paranoid.

[roeme]

The oxidation will rub off with on my finger. I'm just wondering what the effects are of it coming off and flowing into the cylinder with the gas. The instructions for the chem dip mention treating low alloy metals with penetrating oil, but I also don't necessarily want that mixing with the gas.

I'm probably being paranoid.

Yup. That minute amount of crap is come and gone within a few combustion cycles, and unless you dump oil (which is not compressible) down the cylinder, the engine wont care much. That wee bit of oil mist doesn't really matter to anything other than maaaaaybe your nose.

Maybe put them briefly into an ultrasonic bath for a few minutes. The equivalent of hundreds of tiny little fingers rubbing ten-thousands times per second might knock off the oxidation...

[Isoparmesan]

What about spraying them with penetrant lube post dip. Is that likely to have any ill effects?

[Big T]

Just wipe off the residue and squirt some carb cleaner thru the various holes, it will be fine

after you reassemble the carb rack, put the fuel line on, prop up the rack to vertical and run gas into the rack (I use a tiny funnel) It may leak a bit at first, but should seal up
Like Roeme, my 41 year old T still seals fine

You are building this bike for your wife? It better be perfect

[Nessism]

WD-40 helps reduce the chalky residue.

[Isoparmesan]

You are building this bike for your wife? It better be perfect

Yep, pressure's on.

Also, I lucked out on the fuel rail. In the "box-o-parts" that came with the bike were a set of VM carbs for a 650. The fuel rail parts are all the same size and practically new.

[Nessism]

The 650 didn't use VM's, unless you are talking about a Kawasaki!

[Isoparmesan]

The 650 didn't use VM's, unless you are talking about a Kawasaki!

Yeah, I was just doing some googling to double check that. They're definitely round slide carbs and not CV. Did the GS650 have CV? The guy said they were from "a 650" but he could have been wrong. They look nearly identical to the VM22SS's from the gs550, but larger. Either way, the fuel connectors are identical.

Edit: attached a photo. Carb on left is the mystery one. Carb body on right is from the GS550

Edit edit: Actually, googling "KZ650 Mikuni vm" produces images that look just like them, so maybe they are from a kz650.

[Isoparmesan]

I'm sure it will come as no surprise to anyone, cleaning the carbs fixed the idle jet problem!

I replaced all the o-rings, including the carb boot ones. Installed a in-line fuel filter (just the regular trackside one from cycle gear). Also, flushed out some sediment that had built up in the tank with gas. Condition of the tank is fair, but I'm probably going to give it a evapo-rust treatment to get rid of some oxidation on the top most surface of the tank.

As far as the fuel connectors on the carbs, I did end up needing to recycle the original ones. The ones from the other set of carbs were the right diameter, but the wrong length. And, alas, there was fuel leaking from the T-joint last night. However, this morning there wasn't. so, I'm going to subscribe to the theory that the rubber has expanded after soaking in gas overnight.

So, this is the state now. I will start cold with choke, but will backfire pretty consistently. I hear popping come from both the carbs and from the exhaust. Once it's warm and the choke is off, this goes away. It idles just fine. I can give it throttle enough to ride it around, but if I quickly snap the throttle open it bogs, but generally doesn't die.

Would I be correct in thinking the needle jets may need adjustment for this type of bogging? I haven't synced the carbs yet either.

As far as the popping while on choke, would that be a timing thing? I also haven't done valves, or inspected the points, etc.

Sorry if these are dumb questions, I'm really just starting to learn this stuff.

[Big T]

Popping on choke is dirty pilot circuit/jets

You did remove everything from the carb bodies?

[Isoparmesan]

You did remove everything from the carb bodies?

Yes. First attempt, I used an ultrasonic cleaner with vinegar and soaked the brass bits, but didn’t take the upper part of the pilot jet out by mistake. Second attempt I pulled everything out of the carb body and soaked everything except for the choke plunger itself floats, and external screws in chem dip. I did not disassemble the slides, but I did soak/rinse them.

the pilot jets were very clogged, but are completely clear now.