Carb Fuel Leak, Part Swapping

[Klubkrasher]

I picked up a 1988 Katana 600 a few months ago as a cheap, alternate way of commuting and some weekend riding and have been working on it for countless hours. Besides all the obvious and common issues with a bike it's age like: being filthy, being down (who knows how many times), broken parts, missing parts, leaks, and other hidden issues - I have been discovering that the VIN, motor, carbs, and other parts are from different years too. The guy I bought the bike from also gave me two other sets of carbs in addition to the set that was on the bike itself. One set on the bike is from a '93 Kat 600, another the same (which of of course lacks the # 1 carb) and another set seems to actually be from an '88 Kat 600. My roommate pointed out today that the motor has 1990 written on it.

The title that came with the bike was from Arizona and said 1988. I purchased it in Phoenix and hauled it home. It is now legitimately registered and insured with me in my home town of Las Vegas. I have the Clymer guide to the bike as well as doing a ton of research online including the KatRiders.com Forum, suzukipartshouse.com, cheapcycleparts.com, and other motorcycle forums and websites for helpful information.

I spent a decent amount of time and money getting replacement parts and dealing with the gas tank (inside and out), but nowhere NEAR as much time I have spent in the past month trying to get the #1 carb to STOP leaking fuel. A month ago I finally got the bike running after changing the spark plugs, but started noticing the fuel leak coming out of the air jet on the air filter connection side only after a couple days. No leaks out of the bowls, gaskets, or drain holes/screws. I read that the most common issue for this was the float height and the pilot needle not stopping the overflow.

Since having the extra set of '93 carbs (minus the #1), I started taking them apart to learn the anatomy before going to work on the full set connected to the bike itself. After feeling comfortable enough that I could handle, clean, and inspect all the components correctly on the "test" carbs, I went ahead and inspected, cleaned, tried every adjustment, AND part swap physically possible (floats, o-rings, needles, jets, washers, seats, diaphrams, bowls, gaskets --- everything) - but with no luck and the same leak on the original set. I even got help from my roommate who is more mechanically inclined then I am. He also rebuilt the fuel petcock for me. Still, the #1 carb leaked.

Finally, I took the #3 carb from the extra set and converted it to a #1. I thought there was a hidden crack or something within the original #1 carb housing and this would have to solve the issue for sure. Swapped carb still leaked, and I even switched internal parts - again and again - to make absolutely sure. I have taken the gas tank and carb assembly of this bike at least 20 times.

Now, I have all but completely given up on trying to get the '93 carbs to work on the bike, unless anyone can serve up a hidden solution that I am missing?

Meanwhile, I have turned to trying and get the '88 carbs to work. I took them completely apart and inspected, cleaned, put back together, and adjusted everything. All parts and components are in pretty decent shape, just needed a thorough cleaning (two cans of carb cleaner, 1 of canned air).

Over the last couple days I learned that the '88 Kat does not have a choke lever on the handlebar and instead has the starter rail directly on the carb assembly. This was another mind-bender seeing how my Kat HAS a handle choke lever but the '88 carbs have the rail. Another Frankenstein part probably - swapped handlebar or something. Of course, there seems to be a part or parts missing with my particular carb assembly. I looked through all the schematics and diagrams in print and online but can't figure out what exactly I need. I don't have anything that connects the starter rail to the individual choke rods on each carb. I thought I could find the part(s) needed fairly easy (maybe just a rail that connects like the '93's) but am struggling with THAT now.

I'm sure there is a lot of fuel leaking into the engine too because of the carb and that is why I haven't been able to get it started recently either. Until I get this leak fixed though, I don't see a point in changing the oil.

Long post guys sorry, but I appreciate all of your insight and advice in advance!

Thanks.

[Kreylyn]

I picked up a 1988 Katana 600 a few months ago as a cheap, alternate way of commuting and some weekend riding and have been working on it for countless hours. Besides all the obvious and common issues with a bike it's age like: being filthy, being down (who knows how many times), broken parts, missing parts, leaks, and other hidden issues - I have been discovering that the VIN, motor, carbs, and other parts are from different years too. The guy I bought the bike from also gave me two other sets of carbs in addition to the set that was on the bike itself. One set on the bike is from a '93 Kat 600, another the same (which of of course lacks the # 1 carb) and another set seems to actually be from an '88 Kat 600. My roommate pointed out today that the motor has 1990 written on it.

The title that came with the bike was from Arizona and said 1988. I purchased it in Phoenix and hauled it home. It is now legitimately registered and insured with me in my home town of Las Vegas. I have the Clymer guide to the bike as well as doing a ton of research online including the KatRiders.com Forum, suzukipartshouse.com, cheapcycleparts.com, and other motorcycle forums and websites for helpful information.

I spent a decent amount of time and money getting replacement parts and dealing with the gas tank (inside and out), but nowhere NEAR as much time I have spent in the past month trying to get the #1 carb to STOP leaking fuel. A month ago I finally got the bike running after changing the spark plugs, but started noticing the fuel leak coming out of the air jet on the air filter connection side only after a couple days. No leaks out of the bowls, gaskets, or drain holes/screws. I read that the most common issue for this was the float height and the pilot needle not stopping the overflow.

Since having the extra set of '93 carbs (minus the #1), I started taking them apart to learn the anatomy before going to work on the full set connected to the bike itself. After feeling comfortable enough that I could handle, clean, and inspect all the components correctly on the "test" carbs, I went ahead and inspected, cleaned, tried every adjustment, AND part swap physically possible (floats, o-rings, needles, jets, washers, seats, diaphrams, bowls, gaskets --- everything) - but with no luck and the same leak on the original set. I even got help from my roommate who is more mechanically inclined then I am. He also rebuilt the fuel petcock for me. Still, the #1 carb leaked.

Finally, I took the #3 carb from the extra set and converted it to a #1. I thought there was a hidden crack or something within the original #1 carb housing and this would have to solve the issue for sure. Swapped carb still leaked, and I even switched internal parts - again and again - to make absolutely sure. I have taken the gas tank and carb assembly of this bike at least 20 times.

Now, I have all but completely given up on trying to get the '93 carbs to work on the bike, unless anyone can serve up a hidden solution that I am missing?

Meanwhile, I have turned to trying and get the '88 carbs to work. I took them completely apart and inspected, cleaned, put back together, and adjusted everything. All parts and components are in pretty decent shape, just needed a thorough cleaning (two cans of carb cleaner, 1 of canned air).

Over the last couple days I learned that the '88 Kat does not have a choke lever on the handlebar and instead has the starter rail directly on the carb assembly. This was another mind-bender seeing how my Kat HAS a handle choke lever but the '88 carbs have the rail. Another Frankenstein part probably - swapped handlebar or something. Of course, there seems to be a part or parts missing with my particular carb assembly. I looked through all the schematics and diagrams in print and online but can't figure out what exactly I need. I don't have anything that connects the starter rail to the individual choke rods on each carb. I thought I could find the part(s) needed fairly easy (maybe just a rail that connects like the '93's) but am struggling with THAT now.

I'm sure there is a lot of fuel leaking into the engine too because of the carb and that is why I haven't been able to get it started recently either. Until I get this leak fixed though, I don't see a point in changing the oil.

Long post guys sorry, but I appreciate all of your insight and advice in advance!

Thanks.

I'd recomend...

Take all those carb parts and sets including what's on the bike.... take a pic, contact Arsenic, and ask him how much $ to trade those parts for a single good set built right.

Krey

[arsenic]

I gave up reading that. You don't need to take pics of the 88 carbs, I don't want them.

[Klubkrasher]

Yeah, sorry once again for the length of the post guys. I Thought since it was my first post I would risk having too much info versus not enough.

It was a shot-in-the-dark to see if there was something I was missing about the problem with the fuel leak on the #1 carb besides what I had tried already. I also noticed each time the float bowls were drained upon working on the carbs, the #2 had less then the #1, the #3 less than the #2, and finally the #4 had pretty much nothing. Is this normal?

The petcock was cleaned and rebuilt, the fuel and vacuum lines checked out fine, and the hose "splitters" for the fuel in between the #1 & #2 carbs and the #3 & #4 carbs were replaced as well.

Any thoughts on that? Is it possible that it's gravity that's the issue since everything seems fine and the bike in the stand leans to the left towards the #1 carb? I just don't know. As I mentioned in the original long post, I swapped out internal parts in the float assembly and every other part of the carb in the rotation of the 7 carbs that I had and still got the leak each time everything was re-assembled.

Thanks in advance again.

[arsenic]

No, it's not that you have an incredibly long post (which you do). But I'm pretty sure I have advanced ADD.

[Wild-Bill]

Two things you've missed with those carbs. 1. You replaced a few hard-parts but not the float needles or o-rings. Those are generally what needs replacing the most on old carbs. 2. You cleaned the carbs with spray carb cleaner but didn't soak them first. Sometimes that works but frequently not. Once you get the leaking to stop you may find the idle isn't right. It'll be because the small passages inside the carbs are still clogged.

To avoid having to take the carbs on and off the bike, you can test for leaking both by turning the carbs upside down and blowing into the fuel lines (shouldn't be able to) and by filling them on the bench and then trying to blow into the lines. I had a problem set a while ago and found that clamping the carbs in a bench vice made life much easier.

[Klubkrasher]

Well, I did actually put all seven floats w/ all the connecting parts in each (including o-rings and float needles of course). No matter which set was in the #1 carb (which has also been swapped out), the leak persisted. None of the other carbs have ever leaked.

How can this be the carb - or it's parts then - is what I don't understand.

Having swapped out every single component and the entire carb assembly itself, the carb that is in the #1 position on the bike leaks.

Help me guys, there has to be something else wrong here. I mean, I can order rebuild kits and put them in, throroughly clean soak everything again, make all the adjustments, and the leak is still going to be there out of the #1 carb position. As I mentioned, the fuel and vacuum lines, hoses, and petcock all are fine.

Why else can the #1 carb be flooding and overflowing? Can the pressure be too less to the other carbs and too much for the #1 for the float parts to contain it?

If I sound like I'm going crazy the way I'm writing it's for good rerason. I'm stuck on this issue and don't know what else to do!

[sakolig187]

Hey Klub, Im having the same issue with my 93 1100 Kat. Only mine is the 2 bowl in from the right side. Mine is only leaking when I fill up beyond 3/4 of the tanks capacity. Try draining some of the fuel out if there is a decent amount in the tank and see if the problem stops. I am not sure if there is a massive airbox on the 600 like there is on the 1100. Im thinkin mine may be a vacuum problem with the airbox.

Its already almost July so Im gonna fill the tank only half way for the rest of the summer an try to diagnose the problem in the fall/winter.

[Wild-Bill]

Your float needles are worn and leaking or you've got some drek caked on the seats. Soak the seats overnight, replace the needles (or just replace the needles, seats and o-rings on an 1100) and watch the problem go away.

[Kreylyn]

Your float needles are worn and leaking or you've got some drek caked on the seats. Soak the seats overnight, replace the needles (or just replace the needles, seats and o-rings on an 1100) and watch the problem go away.

Or an oring on the float rail is not sealing off (depending on the year).

Krey

[gsx]

I think you should take the carbs off, clean and replace all parts as needed(take the bowls AND the tops and take the slides out. When putting them back together make sure you grease every hose/fitting/gasket. If a gasket is bad, replace it. Also, the carbs should have numbers on them. Start from top and go from there

[Klubkrasher]

Update on '93 carb assembly:

I ordered a set of float bowl gaskets, o-rings, plus bought Chem-Dip. I took apart the #1 carb completely, and soaked the carb body and all metal parts thoroughly. Everything looked fantastic and clean. After putting the carb back together correctly with the new gasket and o-rings, the carb still leaks out of the same location though. Also, the #2 carb is leaking now after not even messing with it at all.

I have been trying to get a hold of mechanics in town with not whole lot of luck. They need the bike as a whole and it doesn't start because of the engine sitting, being flooded, and just not being safe to ride because of the fuel leak and potential fire hazard. It's 105 degrees here of course, so I can't take the risk. I Don't have a way to transport the bike to anyone to fix, and no one is willing to come to the house, so I am stuck.

I have put so much time into these carbs at this point that I have put an Ad up on CraigsList for the bike. Either I get this problem fixed or I sell the bike as a whole for what I am asking for it - whichever comes first.

Guys, I am having a pretty tough time believing that the carb itself is the issue. After doing all of this sh*t over and over, and now completely cleaning these parts inside and out PLUS replacing all o-rings and the bowl gasket. There cannot be anything wrong with the carb at this point. The float needle is perfectly fine, and there are no clogs anywhere. I can safely say that I have enough knowledge at this point in terms of the construction and physics of these particular carbs that there has to be an external issue.

Since the #1 & #2 carbs are fed fuel in the same line, could there be a vacuum issue or pressure / gravity (leveling) problem? How do the rest of the carbs other than the #4 carb get vacuum pressure if the line only connects to the #4 carb and the petcock connection?

Oh, and when the bike is stood up straight and off the sidestand (there is no center stand on the bike) the leak(s) stop.

I also noticed that the rubber seals where the air "nipple" parts connect the lower parts of the #1 & #2 carbs were badly damaged and almost disintegrated. This seems like it could be a potential cause as well, but I just don't know. The more I work on everything and nothing fixes the problem, the less components I rule out to be the issue.

Thanks again for your help in advance guys, I appreciate all of your time.