Suzuki Bandit running problem, can someone help?

[eyeeatingfish]

Im having a problem with my bike so ill list all the infor
2001 Suzuki Bandit 600
4 cylinder, 4 carburator
Just changed the spark plugs

I was going to ride to work and after about a mile of riding i noticed my RPMs were falling. At a stoplight it seemed like the bike was going to stall, I had to hold the revs up to keep it from stalling. I pulled over to the side to play with it and when i let go of the gas the bike stalled. I tried restarting, no luck. I tried playing with stuff, no luck. I ended up waiting about 5-10 minutes calling insurance to get it towed. I tried starting up my bike and it ran fine! I drove a little less than a mile and started having the problem again, so i puleld over and same problem. I decided to drive it home, and waited 10 minutes and it started again. Sure enough the problem came back so i just held the throttle so it wouldnt die till I got home. Even then soemtimes it wasnt responsive to gas while accelerating from a slow speed.
I jsut had the bike for a regular service, so i would expect them to have found something obvious wrong.

I had had problems before i got it serviced that i think stemmed from having the bike sit for 2 months while not being driven. The people at the service station didnt report anything.
There is enough oil.
The battery turns over just fine, doesnt seem electrical.

My best guess is problems with my carburetors. Im assuming they would have caught a dirty fuel filter. I havent pulled off my tank yet but it seems clean.

Thankyou

[eyeeatingfish]

I saw this in someone else post and it described a problem I had been having too. Not sure if it is related

The new problem is that when the bike sits for a few days, it somehow floods the motor to the point where it hydro-locks itself. This is where I have to bump it back and forth in gear to free it up a little, and it eventually will turn itself over,

[mgdavis]

Nope, not related. Clogged vent gas caps? Not enough fuel flowing through the lines? Fouled petcock? Dirty Carbs? Bad fuel? Out of fuel?

[eyeeatingfish]

Full tank of premium fuel, same fuel i always used. The problem wasnt constant, it would kick in after a few minutes of being on, whick leands me to believe someone is becomming clogged up, and since a 5-10 minute wait allows it to start again it makes me think somethine is settling back down or clearing up.

[mgdavis]

Clogged gas cap vent possibly? Try to loosen the cap when it starts to bog, if it picks back up you have a clogged vent. Is the fuel fresh or did it sit in the bike? If it sat in the bike it may need replacing with fresh fuel.

[BuzZz]

What mgdavis was refering to, is the vent in the gas cap being clogged. This will create a vacuum in the tank as gas leaves to be burned by the engine and air can't get in to replace it. Eventually, this vacuum will cause the fuel flow to be reduced or stopped all together. Killing the engine and waiting a few minutes allows air to equalize the tank pressure, and things work fine for a short time, until it happens all over again.

Next time this happens, crack the gas cap with the engine running and see if the problem stops right then.

Got all the sparkplug leads pushed on all the way and making good connection? or a loose ground to the coils? new plugs don't always mean 'good' plugs.

Many plugs are defective right from factory, or very soon after being put into use, and heat can be the trigger. The warmer the engine gets, the warmer the plug gets. Stop and cool it down, problem goes away until hot again. Possible anyways, but it would the last thing I tryed before tearing the carbs down again.

[eyeeatingfish]

Ill check on the valve thing soon. If it isnt the pressure valve what else might it be?
It seems like it wouldnt be the valve because I could keep the bike from stalling by holding the revs up a bit. If it were creating a vacumb wouldnt it restrict me from keeping the revs up too?


Is hydro lock in any way related to this? From an explanation I read it seems like I might have hydro lock somtimes.

[mgdavis]

Thanks for clarifying Buzz.

Definitely not Hydrolock.

[BuzZz]

It could be a vapor lock problem. Those oil-cooled Zuks kick alot of heat back to the carbs and airbox. I've never messed with a 600, but any 750's or 1100's I've dealt with have a cheap heat shield between the cylinders and carbs. It's cheap, but it works. Any modified bike that has had this shield removed has turned into a carburational nightmare. The pod filters that almost always go along with those mods don't help, but anyways....

You may want to trace the fuel line from the tank down to the carbs. Maybe it got re-routed when the carbs were worked on. Especially if someone cut off 2 inches of buggered line and had to cheat that length back, instead of replacing the whole line.

[eyeeatingfish]

I dont think the bikes ever been modified.

I jsut hate to take it in and pay hundreds for someone else to repair it. A cerburetor rebuild is probably out of my skill level.