Choke assemblies leaks

[TheHat]

Anyone have any experience with leaking choke assemblies causing idle issues?

I can't find any specific threads here.

I did rebuild the carbs. However, there is one tiny o-ring remaining for each kit that I wasn't able to locate (thank you whack *** clymer manual).

I'll be using the free manual available here to see if that can't help identify the location of the missing o-ring, but if that's not the issue, can anyone give some insight?

I've confirmed the choke assemblies are leaking via two methods. A. plugging the air inlet to the choke on one carb kills the motor within moments when the choke is in full off position. B. a tech at a local suzuki dealer said outright while listening to it the choke is on, even though it's in full off position. My conclusion, leak at choke.

I'm not familiar with carb motors at all, but I have plenty of experience working with four stroke motors.

I'll check back in the morning before I go pull it all apart again.


Thanks!

1995 Katana 600

[Kreylyn]

Anyone have any experience with leaking choke assemblies causing idle issues?

I can't find any specific threads here.

I did rebuild the carbs. However, there is one tiny o-ring remaining for each kit that I wasn't able to locate (thank you whack *** clymer manual).

I'll be using the free manual available here to see if that can't help identify the location of the missing o-ring, but if that's not the issue, can anyone give some insight?

I've confirmed the choke assemblies are leaking via two methods. A. plugging the air inlet to the choke on one carb kills the motor within moments when the choke is in full off position. B. a tech at a local suzuki dealer said outright while listening to it the choke is on, even though it's in full off position. My conclusion, leak at choke.

I'm not familiar with carb motors at all, but I have plenty of experience working with four stroke motors.

I'll check back in the morning before I go pull it all apart again.


Thanks!

1995 Katana 600

The choke plunger is brass. Over all there is a larger size "piston" shape and on the tip is a smaller "point". A spring is behind the piston, and when seated is always trying to push the piston closed. When closed, the larger piston is in the way of the vacuum and fuel to cylinder delivery ports. Also when closed, the small point is seated against the fuel intake port that routes down to the bowls. The default setup is closed unless something is pushing/holding it open.

No rubber there in how that works. While there is a rubber gasket/boot/oring depending on the bike around the end assembly where the choke rail seats... (opposite end from where the fuel and vacuum ports are in there) that is more so to prevent leaks when the plungers are opened (choke on).

The most likely causes of the issue if you have "leaky" chokes adding fuel... is the choke rail not properly connected to them all or it's bent, the cable is not allowing the rail to fully close, or 1 or more of the choke plungers has encountered a dirty/corroded area inside that is preventing the plungers from moving freely.

A simple test... take the rail off and make sure it's straight. Pull open each plunger and let it go. It should snap shut like you just fired a pinbal plunger. If it doesn't snap shut, you need to clean the inside of the choke plunger seat area... it may have some corrosion build up. Put it all back together, and then verify the choke cable is working right and allows the plungers to fully seat. If when fully closed... the rail should not be pushing/pulling on the plungers at all as the slots on the plungers are larger than the thickness of the rail where it hooks on them.. otherwise it's bent.

Krey

[phantasm]

Left over o ring. A/f screw or vacuum port on the tops perhaps? And forget the manual for carbs. Download carbs 101and from the wiki.

[TheHat]

Krey, you boss, I couldn't have asked for a more detailed description of the choke plunger assembly. I've looked at several parts fiches and talked with the local Suzuki dealers mechanics and until now never had a better understanding of the assembly. You rock!

I can tell you right now I know what it is, and you're right, the rail is bent to ****. I didn't think it was enough to open the plunger on any of the chokes but I'm fairly certain I was mistaken. I'm going to go pull it off, conduct your test with each plunger, run the bike and report back here.

Phantasm, I want to say the A/F screw sounds familiar from the last times I tried to hunt down the missing o-ring. I'm confident I got the vacuum ports on the tops. If I can get it to idle, I'll be less concerned with the missing o-ring.

And yea, trying to work on carbs out of the manual friggin' blows.

Thanks guys!

[TheHat]

Report: Took the choke rail off completely and it idled fine with no tank. Eventually the bike warmed up and the idle went up significantly. Petcock position was 3 o'clock, prime, as I've just read. Previously it refused to run in the 6 o'clock, on, position which is why I always ran prime unknowingly. Any chance running it in prime could damage the carbs? That would suck.

New issue, when running in prime it'll idle for a bit and eventually die. When running in "on" position it runs well for a while and then the idle runs really high. I don't have my tach on but it's gotta be at least 2000 rpm but my guess is higher.

When I rebuilt the carbs I was unaware of float adjustments and I could only clean the jets so well. I'm looking in to a jet kit but wanted to resolve the choke issue first. Would it be advised to get the jet kit installed prior to further diagnostics? As I understand that should eliminate clogging as the culprit and my hope is it would narrow down options.

I believe I'm going to start with finding that missing o-ring until I get some feedback here.

Thanks again.

Carbs101 was amazingly descriptive as well. I'm really irritated I didn't stop here first when rebuilding the carbs as the resources I used were nowhere near as detailed.

And after looking at the pictures in the PDF version, Phantasm you were right, the missing o-ring is for the A/F mixture screw.

[Kreylyn]

If the a/f screws were not pulled and the bodies dipped... the carbs are not clean.

But... the warm engine is when the idle issue starts tells me it's a more likely a vacuum/air leak.

Krey

[steves]

Not sure where you got the rebuild kit, or which rings came with it so it's hard to say for sure.

Try lubricating the choke plungers with a little light oil, I use hoppes #9 myself.

[TheHat]

Yea Krey I definitely didn't access the A/F screw area, and apparently neither did the previous owners who trashed the bikes because they're still plugged.

I agree on the vacuum/air leak. My inspection of the carbs wasn't near as thorough as the carb 101 is, and I was able to recall some trouble spots but they're all internal. I'm thinking a leak like that would be external? Any common leak points I should check?

I printed out the carb 101 with pictures, I'll be tearing them down, reinspecting and removing all jets to prep for jet kit.


Steves, I got them from a local motorcycle salvage place, they ordered them for me. I can post who makes them when I trip back out to the garage if it'll help but there was one tiny o-ring left for each kit and after reading the carb 101 I saw the A/F mixture screw has an o-ring...a tiny one

I'll certainly lube the choke plungers once I put it all back together!

[steves]

carb boots and airbox are the common areas for leaks. Especially with old/cracked/dry rotted parts.

[TheHat]

The vacuum line to the petcock wasn't connected. Major fail. Which explains why it would run in prime but not in on/res.

Okay I reattached the disconnected vacuum line which now links the passenger side carb (carb 4?) with the petcock, is this correct? *Just confirmed via the wiki that the petcock is properly connected at this time* It idles now for a lot longer than before and then eventually dies instead of running high.

It also doesn't run properly at all RPM ranges, however when in prime is does run properly in all rpm ranges it just won't idle.

I do believe it's still a leak between the petcock and carb 4 and I recall the connection at carb 4 being crappy when I rebuilt the carbs.

I'll check it when I get a chance again and report back.

Steves I don't recall any damage to any of the parts between the airbox to carbs or the carbs to engine block but given I missed a disconnected vacuum line, anything is possible at this point. I'll check those again as well.

[Wild-Bill]

Learning has occurred. Check.

It's pretty cool when things click and you figure it out for yourself, huh?

[TheHat]

Lol yea, I had this nagging feeling something was off and I couldn't put my finger on it. I was looking up the petcock positions to confirm I had them right and found a wikipedia page that included symptoms. As I was reading it mentioned petcock vacuum line and carb 4. That's when it donned on me that I had never attached anything to the vacuum port on the petcock and I could never figure out the routing of that line coming from carb 4. It wasn't attached when I first acquired the bike.

After reviewing the wiki here I've confirmed all connections are in the correct place and all ventilation lines are open and free.