Katana GSX600 issue

[kilo1]

Hello, I have a 1991 Suzuki katana 600. I got the thing about a month ago, when I initially bought it I knew an ignition coil was bad so I swapped out the coil. That it was riding OK for a little while, until it started to die every time I come to a stop. So I took the carburetors out and inspected them and put a carburetor rebuild kit into each of the carbs. Fix the timing on the carburetors, because that was all jacked up. Replaced the fuel line, cleaned up the carbs a little bit, and put it back together. It starts after about 10 minutes of messing with it (Unless I spray fuel directly into the fuel box) and will only stay running if I'm holding the throttle at about 4000 RPMs. Anything less than that it will immediately die. Any insight would be amazing. I really want this thing operational. It's my first actual bike. Please help.

[92xjunker]

Carbs are still dirty....how's the tank look? Anything in there will clog your carbs again. Fuel filters will cause other issues.

[kilo1]

Carbs are still dirty....how's the tank look? Anything in there will clog your carbs again. Fuel filters will cause other issues.

Tank looks ok for the most part. You think taking the tank off, dumping the remaining fuel, cleaning it out, and re installing it would help? I considered putting new pilot jets and regular jets in there as well. I think the guy before me raced this thing. It has a H&K exhaust on it, and a performance air filter. I'm thinking he may have put different jets in it and adjusted it to be more "rich". I don't want to race the thing, I want to drive it around town. What would you clean the inside of the tank with? I put seafoam in it the 3 times I filled the tank.

[92xjunker]

Check the tank for rust, including the inside top. Ok, get a stock air filter and airbox if needed. Post up what jets and needles are in the carbs.

[shpielers]

If the tank is rusty, POR-15. Little bit of work, amazing results. Permanent tank liner = no more rust ever. Different brands actually only last a couple years before starting to come undone and clogging the carbs.

Smell the oil in the crankcase, if it smells like fuel, that would explain a lot. (running for a bit then dying is often from being too rich, fuel in the crankcase will do that) if there is fuel in there, change that oil before you try running the bike again.

Possible reasons for fuel in crankcase: float heights aren't set correctly, debris is holding 1 or more floats open and they can't seal shut, wrong oring on the floats and they can't seal. There's others but those are most likely.

When you say you fixed the timing in the carbs...literally no idea what you did. You're using the wrong terminology. Can you describe what you did?


Just reread: bike doesn't die after 10 mins it takes 10 to start.
That's because the carbs are dead empty. It takes a bit for the starter turning over the engine to suck in enough fuel to get it to go. Turn the petcock to prime for ~30 seconds then back to run, will help with that. As far as having to hold the throttle open, do you know what the choke is and how to use it? Cause that's basically exactly what the choke does. Cold engines need some help. If it needs choke past 4 or 5 minutes of running then you've got dirty carbs, specifically the pilot jets, teeeeeeny internal passages. You'll need to properly clean them ie dissassemble each carb body and soak in cleaner for at least 24 hours.

[kilo1]

If the tank is rusty, POR-15. Little bit of work, amazing results. Permanent tank liner = no more rust ever. Different brands actually only last a couple years before starting to come undone and clogging the carbs.

Smell the oil in the crankcase, if it smells like fuel, that would explain a lot. (running for a bit then dying is often from being too rich, fuel in the crankcase will do that) if there is fuel in there, change that oil before you try running the bike again.

Possible reasons for fuel in crankcase: float heights aren't set correctly, debris is holding 1 or more floats open and they can't seal shut, wrong oring on the floats and they can't seal. There's others but those are most likely.

When you say you fixed the timing in the carbs...literally no idea what you did. You're using the wrong terminology. Can you describe what you did?


Just reread: bike doesn't die after 10 mins it takes 10 to start.
That's because the carbs are dead empty. It takes a bit for the starter turning over the engine to suck in enough fuel to get it to go. Turn the petcock to prime for ~30 seconds then back to run, will help with that. As far as having to hold the throttle open, do you know what the choke is and how to use it? Cause that's basically exactly what the choke does. Cold engines need some help. If it needs choke past 4 or 5 minutes of running then you've got dirty carbs, specifically the pilot jets, teeeeeeny internal passages. You'll need to properly clean them ie dissassemble each carb body and soak in cleaner for at least 24 hours.

The work that was actually done to it, it was my stepdad. I was just kind of there watching what he was doing, and soaking up some knowledge. And the carburetors were all different. All four of them or at a different angle as far as open/close. We don't have a tool to properly check to see how close they actually are so we just eyeballed it but it is way better than what it was before we took the carbs out as far as all being lined up the same. To think I'm trying to figure out is, what can I do to get this thing running normal? It won't start for a long period of time, almost like it's not even trying to start you can hold down the start button for five minutes straight and it won't turn over. Let it sit for 10 minutes come back it'll start right up but you have to hold it at 4000 RPMs just to get it to stay running. I took the seat off and while I had it running I sprayed fuel directly into the airbox and I was able to let go of the throttle and it idled for maybe 30 seconds and then died again. Could it be the Jets?

[shpielers]

The different angle thing - that's called syncing the carbs
You'll need to get or make a tool to get it dialed in right, bike wont run well without it. (Google homemade manometer)

If hitting the starter button sometimes engages the starter and sometimes doesn't, I'd guess you have a loose connection somewhere.

Having to hold it at 4000rpm means the pilot jets are dirty, look up carbs 101 in the wiki (upper left) for a how to on carb cleaning. So yes, it's a jet...but it not one of the brass ones that screws out. It's a series of internal passages.

[kilo1]

The different angle thing - that's called syncing the carbs
You'll need to get or make a tool to get it dialed in right, bike wont run well without it. (Google homemade manometer)

If hitting the starter button sometimes engages the starter and sometimes doesn't, I'd guess you have a loose connection somewhere.

Having to hold it at 4000rpm means the pilot jets are dirty, look up carbs 101 in the wiki (upper left) for a how to on carb cleaning. So yes, it's a jet...but it not one of the brass ones that screws out. It's a series of internal passages.

I will definitely have to do that. I just ordered (yesterday) new pilot and main jets for all 4 carbs. And a factory air filter instead of a performance one. I'm going to clean the carbs, and put the new jets in, and then install the new filter. Do you think that alone would most likely fix the issue?

[shpielers]

Just a proper carb clean and new air filter should do it. No reason to replace the jets unless you confirm they are larger than OEM.

FYI, while carbs 101 is great there's a couple things wrong with it. #1 When reinstalling the A/F screws, 2.5 turns out from lightly seated is correct (101 says 1.75 or 1.5) and #2 don't use carb cleaner in a can you just spray at the carbs. To clean those internal passages that are likely causing your problem you're going to have to soak them for at least 24 hours in a cleaner such as Berryman's chem dip. (Most auto stores have it, some Walmarts have it etc) if you're careful 2 carb bodies will fit in the can at the same time. If you dont want to fuss with them for 10 minutes getting them just so, one at a time x 24 hour soak = 4 days, fyi.

Even after you get the carbs sorted, there is likely other maintenance that could use doing. Flush the brake fluid, change fork oil, grease wheel/swing arm bearings, lube cables, adjust valve lash, etc. None of it is hard, none of it might be 100% required RTFN, but the bike will perform better and more safely from it. It's old. It's gonna want/need a little tlc. Give it some, and it'll last a lot of miles. I'm got a little over 110k on mine so far

[92xjunker]

+1

[shpielers]

Forgot to mention, that "performance" air filter....sucks donkey balls. It leans out the mixture way too much. Even experienced people with dyno access have failed to get rid of the flat spot it leaves. So excellent call on going back to stock

[dnelli]

Just a proper carb clean and new air filter should do it. No reason to replace the jets unless you confirm they are larger than OEM.

FYI, while carbs 101 is great there's a couple things wrong with it. #1 When reinstalling the A/F screws, 2.5 turns out from lightly seated is correct (101 says 1.75 or 1.5) and #2 don't use carb cleaner in a can you just spray at the carbs. To clean those internal passages that are likely causing your problem you're going to have to soak them for at least 24 hours in a cleaner such as Berryman's chem dip. (Most auto stores have it, some Walmarts have it etc) if you're careful 2 carb bodies will fit in the can at the same time. If you dont want to fuss with them for 10 minutes getting them just so, one at a time x 24 hour soak = 4 days, fyi.

Even after you get the carbs sorted, there is likely other maintenance that could use doing. Flush the brake fluid, change fork oil, grease wheel/swing arm bearings, lube cables, adjust valve lash, etc. None of it is hard, none of it might be 100% required RTFN, but the bike will perform better and more safely from it. It's old. It's gonna want/need a little tlc. Give it some, and it'll last a lot of miles. I'm got a little over 110k on mine so far

Yea, Krey recommended 2.5 turns out when i recently drilled out my air screw plugs to clean the carbs. When I read that Wiki Carbs it contradicted with what was recommended...I set it at 2.5 out as my starting point. Glad you set that straight for me. haha