Bike sputtering under acceleration

[Halflin]

Hi peeps this is my first post here!

I hang out over @ totalmotorcycle.com but i've been popping in here over the last few weeks.

I need some help please!  

I was out riding tonight having a wonderful time just cruising and when I was on my way home my bike just started jacking up.

When I accelerate the bike starts sputtering, missing, and acting like it wants to die if I give it more then 1/4 throttle. This just started like 15 minutes ago on my way home. While I was out earlier in the evening I was doing roll on's getting the R's up above 8k and no issues @ all. It starts up and idles fine. Seems like all of a sudden I'm not getting gas to the engine.

If it were a fouled plug wouldn't it run like "crumb" even @ idle?

My bike is a 01' bandit 1200.

Thanks for any input,
Half

[et]

Sounds like this started happening when your fuel was getting low; ie getting near reserve.
So could it be either a dirty fuel screen on the fuel pump or maybe water in the tank ?

[Halflin]

Hmmmmm  I did get caught in the rain today for the first time.  Where would it have come in from?  And why didn't it happen sooner?  I did probably 10-15 miles before it started happening.  I was in the rain for maybe 2 minutes.  

I'll take a look at the fuel screen on the pump.  Not quite sure where that is located at the moment.  Still learning about this bike.

Anyone else got any suggestions?  I'm wanting to make sure I know what to look for.

Thanks,
Half

[et]

Hmmmmm  I did get caught in the rain today for the first time.  Where would it have come in from?  And why didn't it happen sooner?  I did probably 10-15 miles before it started happening.  I was in the rain for maybe 2 minutes.  

Thanks,
Half

Water is always in gas; just in very small amounts that gets mixed with the gas from all the vibration of riding/driving.
Hence we usually don't notice it.

Excessive amounts of water that we notice comes from condensation in your tank or bad gas (condensation in the station's tank ?).

It's so odd that you posted this today. Because the same thing happened to me this afternoon.
I got stuck in stop-n-go traffic for about 45 minutes while it was also hot today; and during that time my reserve light came on.
When the traffic cleared I experience the same missfiring as you. The misfiring went away after filling up at a gas station.
I'm going to add some DryGas to my tank and ride the motorcycle down to reserve tomorrow.
If it happens again at reserve; I'll then start assuming a dirty fuel filter/screen.

--et

[HipGnosis]

I strongly suspect bad gas.   2 minutes of rain ain't nuthing (unless your gas cap was open and it was really pouring).

Fuel filters typically don't get 'better' when you add fresh gas.

Fill up w/ some premium at a major name station and/or use some seafoam.
Also make sure your choke is all the way off.

[Ant]

I'm going to go with water in the tank as well. Whether it came from bad petrol or whether it was from a leak somewhere allowing the rainwater in is another matter.
I had this same problem a year ago and it took a while to diagnose but when I pulled the carbs out and the fuel filter there was water everywhere.  

[Halflin]

I'm going to head to the local Shell station this afternoon and see if that makes a differeence.

I appreciate all of your responses!  

Half

[MadMax96]

If you're still having problems - hit up the forums at maximum-suzuki.com for great Bandit 1200 info.  

[merrily]

fuel, air, spark.

if it's not gas, you could check your battery connection.  a loosened screw at one of the battery terminals will also cause backfiring and missing conditions.  

m.

[Halflin]

Well I went and filled up, rode it about 2-3 miles and it's still doing the missing.  I will give it a good handful and @ about 4-5k it will act like it wants to die.  Did I run it long enough?  

Fuel filter next I guess.

Thanks,
Half

[jschmidt]

I strongly suspect bad gas.  

or a clogged filter or perhaps a clogged tank vent or possibly a collapsed fuel line. If there is no fuel quality or volume problem, it's a bad coil. But this stinks like a fuel problem. Run through your fuel checks.

There is an outside chance it is a bad coil or igniter but this one stinks like a fuel problem.

[MadMax96]

Well I went and filled up, rode it about 2-3 miles and it's still doing the missing.  I will give it a good handful and @ about 4-5k it will act like it wants to die.  Did I run it long enough?  

Fuel filter next I guess.

Thanks,
Half

Did you put a fuel filter on the bike?  I don't think they come stock on the Bandit (doesn't on the pre-01 1200s anyway).  You probably have something clogged in the carbs.  Get some Seafoam and run it through - I've heard this stuff works wonders.  For me, I would just pull the carbs and go through each jet, an easy task with pod filters and no airbox.

Good luck.....

[MK96xj]

Run some good pour in carb cleaner and give it a good shakedown run. See if it clear up.

[MuddDawg]

These things have vacuum operated petcocks, so check the vacuum line.  

Might want to check the kickstand kill switch too.   Usually happens on dualsports when you go over bumpy roads, but it the kickstand spring is weak( don't know why it would be, but) it will kill the engine like putting down the kickstand.

[Halflin]

Being a Bandit nooblet I didn't know there wasn't a fuel filter on there.  Thanks for the info and time saved I would have spent looking into that.  Damnit I need a manual for this bike.  I'll look into getting some carb cleaner for it.  I will also check @ the fuel lines and vacuum hoses.  I'm more convenced that I got something blocking my fuel delivery but I will look @ everything I can.  It's just finding where!!  Thanks for the input guys!

Half

[Halflin]

Well the carbs are off and taken to my buddy Jerry Konsinki @ Jerry's Triumph here in Little Rock, Ar.  He said he'll look at them today if he has time.  Hope that's the problem...

[et]

I strongly suspect bad gas.   2 minutes of rain ain't nuthing (unless your gas cap was open and it was really pouring).

Fuel filters typically don't get 'better' when you add fresh gas.

Cleaning my fuel filter helped me.  
cross post from http://www.sport-touring.net/forums/index.php/topic,14541.0.html
before cleaning:


after cleaning:

[Halflin]

LOL..

It's funny you showed me that cuz I saw it on your post last night.  I took the fuel filter out of my tank (connected to the petcock) and it looked brand new.  Did that one come from your tank?  That's scary if it did.

Anyway back to my problem.  Jerry (my machinic) said he didn't find anything when he tore into the carbs, I was bummed.  So I took them home and slapped them back in and there doesn't seem to be the problem anymore.  I haven't had a chance to actually ride it (raining) but I've had it running for 20 minutes.  Revving it up to 9-10k and no problems.  Holding it @ 3-4k and no problems.  Before it would die if I gave it lots of gas..  Seems there was something in there that came out when I emptied the gas out of it.  That's the only thing I can think of.   Anyway, I'll try to get on it tonight and see if it's actually "fixed".

It was damn fun to take the carbs out myself!!  I've had lots of dirt bikes back in the day but never an inline 4.  

Thanks,
Half