Carbs not getting any fuel, please help!

[alun111]

Hi all,

I have a problem with my bandit 400, it cut out the other day 50 miles from home so I had to get recovery!

I have just fitted a new (to me) tank as my old one had a lot of rust in it. For that reason I had an inline fuel filter fitted (and still have). I have had this type of filter fitted for around a year and haven't had any fueling problems. I have been replacing it every so often with the same brand and type as and when it gets clogged with rust.

The problem is that the filter will no longer fill up with fuel (even after the carbs have emptied making the bike stall). If I fill the line manually the fuel goes it to the carbs until it backs up the line and fills the filter too. If I then connect the tank again (vacuum hose too) and run the bike it will cut out after about 5 mins (with the filter still full). If I then disconnect the tank, the fuel in the filter empties in to the carbs.

I have tried doing all of this with the tank cap open, with no difference. I have also verified that the fuel tap is working by pulling the fuel hose off the tank when the bike is running.

My mum's partner suggested looking for an air leak, but armed with a can of carb cleaner, I couldn't find one at all.

Has anyone got any suggestions? I'm totally stuck on this.

Thanks
____________________
Summer: '00 Honda CB600F Hornet
Winter: '93 Suzuki GSF 400 Bandit VP Variable Valve
Past Bikes: Lifan LF100-5 Lifan LF125-A Honda C70

[haroman666]

You've connected the vacuum pipe that runs from Cyl 1 inlet rubber to the fuel tap??
____________________
The mistresses: 2000 Honda CBR600f, 2000 Honda VTR1000

[alun111]

Hi,

Yes, fuel tank connected correctly. I've even ran the bike with a makeshift fuel tank (with a vent hole), and it still won't allow fuel out of the fuel filter until i disconnect the fuel tank. This means that i can only ever run the bike until the float bowls empty, then I have to manually fill the line again.

Thanks
____________________
Summer: '00 Honda CB600F Hornet
Winter: '93 Suzuki GSF 400 Bandit VP Variable Valve
Past Bikes: Lifan LF100-5 Lifan LF125-A Honda C70

[J.M.]

Have you checked your vacuum? Vacuum not working properly = no fuel.

I'd also remove the fuel filter. Re-install it after everything is working properly.
____________________
2004 R1 & 2018 XSR900

[Pete.]

Do the carbs fill up when you turn the tap to prime? Do they fill up with the filler cap open?
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[alun111]

Hi,

J.M - yes the vacuum is working properly, it still does this with a make shift tank (that doesn't operate by vacuum)

Pete - no prime position on the tap, and again have tried with a make shift tank with no difference. Still no fuel flow with cap open.

Thanks guys
____________________
Summer: '00 Honda CB600F Hornet
Winter: '93 Suzuki GSF 400 Bandit VP Variable Valve
Past Bikes: Lifan LF100-5 Lifan LF125-A Honda C70

[alun111]

Hi,

J.M - yes the vacuum is working properly, it still does this with a make shift tank (that doesn't operate by vacuum)

Pete - no prime position on the tap, and again have tried with a make shift tank with no difference. Still no fuel flow with cap open.

Thanks guys
____________________
Summer: '00 Honda CB600F Hornet
Winter: '93 Suzuki GSF 400 Bandit VP Variable Valve
Past Bikes: Lifan LF100-5 Lifan LF125-A Honda C70

[P.]

Umm, you should have prime on there as its a vacuum tap. There is a pipe that heads from the back of it to the inlet on Cyl 1 as stated above.

[Pete.]

[Scotsman37]

You said you got a different fuel tank for the bike did you swap over the your fuel valve onto the replacement tank or used the one that came with it, and therefore I would inspect that the fuel valve was installed properly plus blow out the vacuum hose with carb cleaner and/or can of compressed air in case of an obstruction clogging it up!


You have remembered to reconnect the fuel pump plug?

[alun111]

Hi,

Paddy - The bandit 400 tap doesn't have prime, just on and reserve.

Pete - Yes, no fuel flow, even with the makeshift tank. If I squeeze the fuel line the filter fills up, but won't be gravity fed even if the bike is running. It won't draw from the fuel in the filter until I disconnect the tank. It's like there's a vacuum, but the fuel tank is vented properly.

Scotsman37 - I used the fuel tap from the new tank (but all this happened before I fitted the new tank). As I said, this happens with a make shift tank too, that doesn't require a vacuum. The bike doesn't have a fuel pump.

Thanks very much again!
____________________
Summer: '00 Honda CB600F Hornet
Winter: '93 Suzuki GSF 400 Bandit VP Variable Valve
Past Bikes: Lifan LF100-5 Lifan LF125-A Honda C70

[haroman666]

You could try without the filter?

I ran my B4 for a year and a half without an inline filter and I had zero problems with anything that an inline filter would be concerned with...

The fuel tap has a little gauze bit inside the tank anyway so most bits of shit wont make it past the tap anyway.
____________________
The mistresses: 2000 Honda CBR600f, 2000 Honda VTR1000

[moonzoomer]

Not sure where the tank breather is on these bikes, try opening the fuel filler cap allowing air to enter the tank and see if that helps.

[moonzoomer]

Have you checked the carbs are not clogged with muck? have you tried loosening the drain screws on the float bowls as if the carbs are full already they will not fill but leave an airlock in the fuel line. Try loosening one of the float bowl drain screws to see if the fuel flows.

[orac]

bandit 4 tap does have a prime, pointing strait up. when was the last time the carbs were cleaned?

if you had issues with the tank dumping fine rust into the carbs you will have issues with the floats sticking which as we all know will stop fuel draing out of the fuwl filter.

got a picture of the fuel filter you are using
____________________
Current rides - 2016 Triumph Street Triple Rx, 1994 Suzuki Bandit 400 VM, TGB 204 Classic 125cc
"with nothing left to lose, there is everything to gain. It's not the size of the dog in the fight, it's the size of the fight in the dog"

[alun111]

I might try as suggested to remove the filter for now and see if it makes as difference. The thing is I've had one installed for about a year with no problems though, so I don't know.

It's not a tank breather problem, as I have also tried it with a different tank.

The bike runs fine when there's fuel in the line so I think the carbs are fine.
____________________
Summer: '00 Honda CB600F Hornet
Winter: '93 Suzuki GSF 400 Bandit VP Variable Valve
Past Bikes: Lifan LF100-5 Lifan LF125-A Honda C70

[temeluchus]

one way to check if the fuel tap is working it to suck on the vacuum hose like a choirboy sucks on a clergyman's cock.
____________________
Some shite cruiser. Now with guns and FREEDOM!

[Pete.]

[orac]

just well do a full strip and clean of the carbs just to make sure that the jets aren't blocked or partialy blocked.
____________________
Current rides - 2016 Triumph Street Triple Rx, 1994 Suzuki Bandit 400 VM, TGB 204 Classic 125cc
"with nothing left to lose, there is everything to gain. It's not the size of the dog in the fight, it's the size of the fight in the dog"

[stickybackbob]

Captain Obvious here (or is it oblivious) - could be as simple as a blocked filter?

OP states that fuel won't fill the bowls under gravity and runs for a few minutes (fuel in the bowls) but stops even when there is fuel in the filter. The 'manual' filling of the bowls, line and filter appears to be being done under pressure.

[alun111]

Hi again,

Orac, the filter looks indentical to this, just bought from a local motor factors instead.

As said before my fuel tap only has two positions - on and reserve.

I may well strip and clean the carbs as you suggested

Thanks

Stickybackbob - the filter is new (replaced it as part of diagnosing this). It did the same with the old one, but I have been using this type of filter for a long time with no issues.

Thanks again everyone
____________________
Summer: '00 Honda CB600F Hornet
Winter: '93 Suzuki GSF 400 Bandit VP Variable Valve
Past Bikes: Lifan LF100-5 Lifan LF125-A Honda C70

[Scotsman37]

Double check float valve just in case they are sticking only slowly allowing little or fuel through at all maybe the case? Try using a piece of rolled up fine wet & dry sandpaper on the inner walls where float valve slides to remove any possible scum build up because if it looks ok there maybe a layer of it preventing it moving smoothly which would cause fuel starvation! Finish off with carb cleaner and do what is suggested in cleaning the remainder of the carbs!

Good luck!

[P.]

[Fizzer Thou]

I read a while ago about either someone on this forum or another,that had a problem with an in-line filter causing lack of fuel flow.As a way of diagnosing the problem,as has been suggested,remove the filter and see what happens.

When the in-line filter was installed,was a suitable length of the fuel hose chopped out?It may be that when the tank is being lowered after all is connected,that the hose is getting kinked?I had this problem a while ago on a GSXR750
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[alun111]

Paddy - my tap does not have a prime position.

Scotsman - thanks for the cleaning tips, I will strip the carbs tomorrow!

Fizzer thou - thanks for the tip, I am going to remove the fuel filter tomorrow and clean the carbs while I'm at it. The fuel lie is not being kinked or pinched.

Thanks
____________________
Summer: '00 Honda CB600F Hornet
Winter: '93 Suzuki GSF 400 Bandit VP Variable Valve
Past Bikes: Lifan LF100-5 Lifan LF125-A Honda C70