advice on checking carbs

[tom_eaton]

my bandit wont start.  she turns over without a struggle but the engine just wont catch. i've checked the fuel line, fuel's flowing through, inline filter is clean. ive checked each spark plug, all 4 are sparking ok. i went into garage, and they said it might be carbs. i'd like to fix this myself if possible (a) to save money and (b) to learn how to!

how do i check the carbs, and what do i look for? also, if you have any other ideas on what to check i'd be really grateful.

it's a bandit gsf400 btw

 

[Red01]

The carbs will have to be pulled & disassembled. Probably dirty, so will need a good cleaning.

Has it sat for any length of time withgas in it that wasn't treated with a fuel stabilizer like StaBil or Seafoam?

[tom_eaton]

has been sat for about 2 weeks or so in its new home. rode it home from 10 miles away, ride was fine. turned off fuel tap + left it till 2day (couldnt ride it till today).

just looked, fuel does look a little cloudy.
should i change the lot?

[Red01]

Can't hurt.

Does it smell like gas, or is the odor worse?

[PitterB4]

Did you happen to run it out of gas or drain the gas out of the carbs for any reason?  If so, it takes A LOT of cranking to refill the bowls.

[tom_eaton]

it almost smells like fuel with glue in
 


it hasnt been run dry afaik

[tacoman]

You probably have bad gas, even though its only a few weeks old.  It may have been bad when you got it.  Old, contaminated with water, etc.  I'd say take off the tank and drain it and drain the float bowls.  Refill and set the carbs to "prime" and make sure your battery is fully charged.  Hopefully this will work and the bad gas didn't gum up the carbs.

[tom_eaton]

may seem silly but are there any guides to draining/restting carbs on the net? am trying to drain tank as we speak, but not having much luck so far (think pump is vacuum operated).

[stormi]

You don't have a fuel pump in there.  It's all gravity fed.  There are two hoses connected to the fuel petcock.  One ( the bigger of the two) that feeds fuel, likely this is the one you're trying to drain with?  Remove the second hose (Vaccuum) from the petcock as well, you should find that fuel pours out of the petcock now.

You can find the link to both the service manual and the owner's manual in the Members Only section of the BBS.   They describe a little bit of what you're asking for.

As for your cranking problem.... check that the choke isn't stuck on ( i.e. the cable isn't seized or anything) and that the throttle isn't on just a little.  ( for instance, once you get down there, you'll see where the throttle cable pulls at the carb end.  Make sure that with the throttle cable at rest, that it's against the stop,.. not up a little.  

This bike is very touchy about "extra" fuel when starting, and it's easy to flood it.  we went through a lot of the symptoms that you describe, and both times too much fuel due to misrouted, or stuck cables had much to do with it.

After this,.. you might have to go into the carbs, but start with the easy stuff first.

Also, were the plugs wet at all when you checked them?

If you can't find the drain screws for the carbs, I'll try to get out to the shed today and post a picture of where they live.

You have an "off" position on your petcock? I wonder if that's a UK feature...

There's also the "Italian Carb cleaning" method... but that will only work once you get it started...

[tom_eaton]

i'm guessing that the fuel tank is clogged then. the tank is sat in the bathroom, with only the larger fuel pipe. nothing is coming out. wierd, cz i rode it home about 2 weeks ago. im gettin confused with the whole thing now. and turns out i dont have an off position, theres ON and RES.

[stormi]

i'm guessing that the fuel tank is clogged then. the tank is sat in the bathroom, with only the larger fuel pipe. nothing is coming out. wierd, cz i rode it home about 2 weeks ago. im gettin confused with the whole thing now. and turns out i dont have an off position, theres ON and RES.

OK,.. truth be known, that's how I've read it should work, I'm not sure it's ever worked that way for me.  

On that petcock, do you have a little screw that stops the dial from being able to turn to the top?  If so, remove that, and turn the dial thingy so the arrow points up.  That would be the prime position.  That should "bypass" the need for vaccuum, and let it dump the gas.

I'm sure that someone here will be able to help you.  post anything you can think of that you noticed about the situation, even if it seems irrelevant.  That will help to determine the problem.  

Fuel issues can be tricky and frustrating, but stick with it, eventually they make sense.

[tom_eaton]

right, decided to remove the fuel tap bit. took one screw out, and gas came flooding through. am filling containers atm. will look at petcock when it drained
think im gna have to treat the inside of the tank neway.

[stormi]

you mean one of the mounting bolts?

Is there a screw on the face of the petcock?  Where it says Res and ON?  It should live just above the res label.  If so, that screw blocks the ability to "Prime" the carbs, you will want to know this when you put everything back together.  It will save you cranking and cranking to get fuel in the bowls.

Russtang is hosting the manuals for that bike, go here for login information:
http://forums.banditalley.net/viewtopic.php?t=877

[Russtang]

Here is a crappy little sketch I drew when I was trying to figure out how the fuel valve worked.  



It shows the three positions you can turn the valve, along with fuel flow status (with no vacuum applied).

The screw Stormi is referring to is located in the top picture (around 11 o'clock).  Remove it and you can turn the valve to "prime" (lowest picture).

Russ

[tom_eaton]

cool. will check the carbs 2moro + clean out the fuel tank. i might sort it with kreem or por-15 or something like that first tho.