New to the Bandit world, shame the bike doesnt work..

[TheKillerB]

its possible for gas to go down the vent line if the diaphragm goes bad on the pet-cock.

It sure is, that's what happened to my bike.

[Bandit]

Even if the fuel petcock is faulty, the valve is always open letting fuel into the float bowls, but there is still the float which will regulate the fuel into the float bowl.

The float will rise when the bowl is full and the needle will then shut off fuel into the bowl just like how the toilet flushing system works.

The valve is not always open on our bikes, that's why we don't have an "off" switch on our petcocks.  Fuel only flows to the bowls when there is vacuum (engine running).  That's why there is a vent tube running from the pipe intake between the carb and cylinder on #1 up to the petcock.  The diaphragm that opens with vacuum sometimes tears with age so that the engine vacuum sucks fuel through that tear and straight into that intake.  Eventually all carbs stop getting fuel when the tear gets bad enough and fuel dumps straight down the vacuum tube and into the #1 cylinder.  So the tearing is a steady progression and carbs slowly lose fuel.  That's why you get the poor idle, surges and eventual completely dead and non-starting engine.

Thanks for clarifying, I tot the vent tube you guys are toking abt is refering to the carb vent tube(corrugated hose above the air box). I understand the part where our petcock is vacuum operated because normally when I syn my carb I connect a longer hose to the vacuum hose and fuel hose to supply fuel from the petrol tank to the carbs.

I'm sure the damage on the diaphragm inside the petcock is clearly visible when it gets deteriorated to the stage when the vacuum is sucking all the fuel to cyl 1, by dismantling the fuel petcock. I have open and inspect my ex gsxr750 petcock before, and I think suzuki does not sell any repair kit for the petcock.

[Nige]

Hey guys, this is better than a mechanic any day   Thanks for all the feedback and putting up with me. One thing, the bike only stopped running after it got knocked over, could this be a clue to anything or maybe just a coincidence??

So next step for me is to check if the fuel petcock is broken, I'm guessing this is a simple procedure, any tips?? Gonna go and look at previous posts to see if I can pick up any info.

The manual is great, thanks echomadman. Now to find someone with a decent internet connection to nab it for me  

God damn 56k dialup modems!

Nigel

[TheKillerB]

When the bike wouldn't start, was the starter still cranking?  When these bikes fall over, often the fuel dumps out of the carb bowls.  Because fuel only flows with vacuum, it takes a lot of cranking of the starter to fill the bowls enough for the bike to start.  Mine often drained the battery completely before it would start.  In my case I would then jump the battery with a car to get it started.  LET ME STATE, MANY WOULD TELL YOU THIS PRACTICE OF JUMP STARTING WITH A CAR IS ILL ADVISED AS IT COULD POSSIBLY DAMAGE THE CDI.  That said, it has never damaged mine.  If you do opt to jump with a car, DON'T HAVE THE CAR RUNNING!  I really don't understand why Suzuki didn't put a priming circuit on our b4 petcocks.  Anyhow, just be aware that after a tip over or running out of fuel, you will need to do A LOT of cranking before it will fire up again.  Best of luck to you Nige.

[Nige]

Thanks    gonna need it.
Just a note, when I tried to start it up after it being tipped, all I got was a single 'click' noise from the battery area. I checked all the electrics (wahey, something I DO know about) and everything was fine, this is the reason I opted to take it to the garage to let them at it, and then it came back with the £350-450 Broken head gasket note on it.
   Prodding you guys for everything you know!!

I wonder why there are so few (if any other than me) UK b400 riders who use this board, time to spread the word my side of the atlantic I think  

Nigel

[Bandit]

Hey guys, this is better than a mechanic any day   Thanks for all the feedback and putting up with me. One thing, the bike only stopped running after it got knocked over, could this be a clue to anything or maybe just a coincidence??

So next step for me is to check if the fuel petcock is broken, I'm guessing this is a simple procedure, any tips?? Gonna go and look at previous posts to see if I can pick up any info.

The manual is great, thanks echomadman. Now to find someone with a decent internet connection to nab it for me  

God damn 56k dialup modems!

Nigel

If the bike only stop running after falling over  I believe its not due to the petcock. To check if there is fuel in the float bowl, use a phillip screw driver to loosen the float bowl  drain screw you should able to see fuel dripping out, if not than its time to fill those up.

To fill the empty carb w/o cranking until the batt voltage low, here is what I normally do after I clean my carb. I pump fuel out of the petrol tank into a bottle. Then fill the float bowl by pouring the fuel from the bottle, using a small funnel slip on the fuel hose. It also helps if you can off the headlight when cranking because the headlight draws the most current. Hence I have connected a on/off switch to the headlight.

You should also check to see if the spark plugs are wet, as the cylinder could be flooded with fuel from the carb when the bike topple. Remove the plugs and dry them, leave them outside for 30mins to allow fuel to evaporate from the cylinder before reinstalling the plugs.

[Bandit]

Thanks    gonna need it.
Just a note, when I tried to start it up after it being tipped, all I got was a single 'click' noise from the battery area. I checked all the electrics (wahey, something I DO know about) and everything was fine, this is the reason I opted to take it to the garage to let them at it, and then it came back with the £350-450 Broken head gasket note on it.
   Prodding you guys for everything you know!!

I wonder why there are so few (if any other than me) UK b400 riders who use this board, time to spread the word my side of the atlantic I think  

Nigel

You only heard click sound when pressing the start button??? sounds to me your starter motor is not turning it could be the fall have damge the starter motor carbon brush.

[banditcilik]

A click? I think it might came from the starter solenoid located somewhere near the battery. And if it is not cranking I guess Bandit is correct. But spend some time checking the connection of the starter system. I think it is better than to tear the starter motor and just to find that some wires is disconnected.

[Maniac]

However I did check in the coolant and there did seem to be a kinda browny deposit at the bottem??? It seemed pretty full to me. Sigh, it just keeps getting more and more confusing.

Rust or other 'dirt'. Drain cooling system and flush/refill. This is a common issue, especially if maintaince on the cooling system hasn't been performed as per instructed by the manual. If it was oil, or even fuel, there would be the rainbow-effect on the surface, since oil/fuel is lighter than water/antifreeze (both have the same specific gravity, hence why they mix). I'd do this soon, if the gunk in the bottom gets bad enough it could cause damage to the water pump, or clog up one of the water pathways in the motor. Being an aluminium block/head, that would be bad if you overheated (could lead to a warped head).

It does sound to me like your petcock is probally leaking, very similiar symptoms to what my '93 did! The bike always seemed to be flooded in the morning, even before I would try and crank it, with moisture that smelled like gas in the cylinders (turns out it was, go figure!).

By the way... welcome aboard!

[Maniac]

Oh, and as to the 'click'...

My bike was doing that too. Guess what? It was the bloody petcock. The motor hydrolocked, after removing the plugs it would crank (fountains of gas shot from the holes!). She fired immediatly after, one new petcock and an oil change later she ran great...

Until I moved and lost the keys.  

I'm not saying the petcock -is- the issue, I'm just saying that it could very well be. The vacuum petcocks these bikes have are just plain old prone to having their diaphrams rot out.

[Bandit]

To check if the petcock diaphragm is really cracked and fuel leak into cyl #1 before paying $$ for a new petcock

1. Remove the fuel tank and support it firmly somewhere such that is higher than the bike.

2.Connect a clear hose to the 'vac' side on the petcock and connect the other end to cyl #1 vac hose

3. Connect a clear hose to the 'fuel' side on the petcock and leave the free end connected to a empty bottle and start the bike. (the reason is to clear the airlock to let the fuel flow, the bottle is to catch the fuel.)

4. When fuel start to flow connect the free end of the clear hose to the carb fuel hose

Start the bike again and you should be able to see from the clear hose if fuel is flowing into the carb and see if fuel is sucking into cyl#1. The above mentioned method is how I use to supply fuel to the carb while syncronising it.

[PitterB4]

Good ideas Maniac and Bandit.  I was thinking the starting problem was hydrolock, too.  When my petcock went, I didn't need to do anything fancy to figure it out.  When I popped the tank, gas kept coming from the fuel-line port on the petcock.  It was in Prime postition permenantly.  Fuel coming through the vac line would do it too.  Good luck!

[verdomde]

Just a note, when I tried to start it up after it being tipped, all I got was a single 'click' noise from the battery area. I checked all the electrics Nigel

Did you check the reg/rec and the battery when you checked the lectrics. My reg/rec bust and my battery acid dried up (you should confirm this is not the case visually too), and all i got when starting it was the click. Inspect it for visible damage from when the bike was knocked over too.

My petcock is bust too- i know because when I remove the tank there is freeflow (and heavy) of petrol out of the fuel line (whereas the petcock stopped the flow before). If I disconnect and block up the vacuum hose and the attachment bit on the petcock will my bike run ok?

[Thief400]

My Canadian Bandit has a prime circuit on it

[Maniac]

My petcock is bust too- i know because when I remove the tank there is freeflow (and heavy) of petrol out of the fuel line (whereas the petcock stopped the flow before). If I disconnect and block up the vacuum hose and the attachment bit on the petcock will my bike run ok?

Thats one option!

You can block both ends of the vacuum line with caps and install an inline fuel cutoff valve between the petcock and the carburators. Just remember to turn it off when you park, or else you may get fuel leakage past the floats.