GN250 fuel problem

[qazyy123]

Hi, i got my first bike a few weeks ago, and it has a problem with bogging down every now and then.

Checked the fuel strainer and found some black powder in it, so i drained the petrol tank and flushed a bit more petrol through to see how much of it i could get out. i managed to get quite a bit out but am still having problems.

So how would i go about cleaning out the petrol tank properly to get all the stuff out? and will i need to clean out the carb too?

Thanks.

[The Pastor]

yeah you will most likely need to clean the carb. I'd recommend George from motorcycle doctors to get ur bike running good. hes pretty top notch

[qazyy123]

thanks, but i think it would probably be a bit difficult getting the bike up to auckland at this stage, plus id rather try things out myself. just have no idea how id go about cleaning out a fuel tank really. And will it damage the bike riding in the mean time?

[Gibbo89]

thanks, but i think it would probably be a bit difficult getting the bike up to auckland at this stage, plus id rather try things out myself. just have no idea how id go about cleaning out a fuel tank really. And will it damage the bike riding in the mean time?

Hey mate, good luck with your issue... someone will be along soon to help you out. As for riding the bike, does it bog down anywhere is the rev range? Or at certain speeds and constant revs in the same place? I wouldn't of thought that the bike could be damaged from bogging down, but I'm no expert. Can you 'power out' of the bogging, or what do you do?

[hayd3n]

have you pushed the choke completely back in?

[qazyy123]

Hey mate, good luck with your issue... someone will be along soon to help you out. As for riding the bike, does it bog down anywhere is the rev range? Or at certain speeds and constant revs in the same place? I wouldn't of thought that the bike could be damaged from bogging down, but I'm no expert. Can you 'power out' of the bogging, or what do you do?

it doesnt matter where in the rev range, and i cant power through it, and can last anywhere from a few seconds to ten minutes or so before it comes right again.


have you pushed the choke completely back in?

yup choke is always pushed back in.

[BASS-TREBLE]

May sound stupid, but whats your idle set at?

[qazyy123]

May sound stupid, but whats your idle set at?


that could be relevent actualy. its set at about 1500 when its hot, i know this is too high and havnt got around to changing it yet. How could that effect the bike the way it is though?

[notme]

If the black powder is coming from something in the fuel system, you need to find the source before giving the tank a clean, or it's just a temporary fix.

To clean the tank out, if it's just loose material in there from another source - use petrol. Give it a good swirl around and tip the tank upside down to get the petrol out while it's still moving, that way it will carry the gunk with it. Give it a final rinse with Methylated Spirits to get any moisture out and Bob's your Aunty's live-in lover.

A can of carb cleaner for the carb (surprisingly) might be all that's needed, but if the black stuff has gotten into the jets valves etc it might need to be taken apart.

What's the black stuff look like? Fine powder? Chunks of various sizes? Flakes of material? Could be from inside the tank, deteriorating fuel lines, something that got dropped in at some stage...

[qazyy123]

the powder is fine and black, and definitly coming from in the fuel tank somewhere. for now ive just gone and bought an in-line fuel filter, and that seems to be doing the trick so far.

and thanks, i will try the methylated spirits thing soon too.

[FJRider]

At the bottom/side of the carb is a brass (usually) hex head with a slot (for a flat head screwdriver) ... this is the drain for the carb. Turn the fuel tap to OFF and unscrew the drain plug, dont loose it ...Then after it's removed ... the fuel will drain out of the carb. Within a few minutes it should stop. after it has stopped ... turn the fuel tap to on/prime and let the fuel flush for a few SECONDS ... then turn to off again. Replace the plug ... turn fuel to on/run ... TEST RIDE ...

A (clean) rag under the carb will catch the fuel and show if any crud was flushed out.

[Mom]

Be brave and take that carb off and clean it out, it is not a big job. I would also suggest you clean out your tank properly and seal it so you dont get anymore sediment from the inside of the tank.

http://www.kiwibiker.co.nz/forums/showthread.php/110215-Mom-gives-the-Blue-Lovely-a-Blow-Job

If I can do it anyone can.

[qazyy123]

Be brave and take that carb off and clean it out, it is not a big job. I would also suggest you clean out your tank properly and seal it so you dont get anymore sediment from the inside of the tank.

http://www.kiwibiker.co.nz/forums/showthread.php/110215-Mom-gives-the-Blue-Lovely-a-Blow-Job

If I can do it anyone can.

Thanks, i think this is what ive been looking for. Where would i buy the tank cleaning stuff? and any idea on how much this could cost me?

[hayd3n]

Thanks, i think this is what ive been looking for. Where would i buy the tank cleaning stuff? and any idea on how much this could cost me?
superchurp or ripco

[Mom]

Thanks, i think this is what ive been looking for. Where would i buy the tank cleaning stuff? and any idea on how much this could cost me?

Not 100% sure, but I think it cost about $90. I got my Por15 kit from Repco. Best of luck with it. Be REALLY careful to protect your paintwork from the chemicals, and be specially vigilant about the actual sealer. It really sticks like shit to a blanket :yes:

[qazyy123]

Thanks guys. got the por15 kit and now the bike is running sweet. :woohoo:

[qazyy123]

Nevermind. spoke too soon. The problem has just started again today. was told it could be a fuel mixture problem, but would that cause the bike to bog down intermitently? cause i think it would be a constant bogging down if fuel mixture was a problem. Not sure though.

[notme]

Have you still got black powder in the filter?

[qazyy123]

Nope, fuel is coming through cleanly now, was the first thing i checked.

[notme]

So it was either something else as well, or the black gunk is further down the system. It might be time to strip and clean the carbs....follow FJrider and Mom's suggestions and hope that you find gunk in there, flush it out, put it back together and have a sweet running bike!

[TOTO]

I had similar problem with my GN, All I did was to get a fuel filter installed and problem gone :)

[lone_slayer]

Iam getting the bogging down on my gsxr250 and iam pretty sure its due to an air leak between the carbs and the engine (inlet manifold) on mine they are rubber boots spray some start ya bastard or similar on it around it etc and see if the idle changes. Will hopefully have mine sealed up in the next few days....

[qazyy123]

Iam getting the bogging down on my gsxr250 and iam pretty sure its due to an air leak between the carbs and the engine (inlet manifold) on mine they are rubber boots spray some start ya bastard or similar on it around it etc and see if the idle changes. Will hopefully have mine sealed up in the next few days....

Is your bogging down constant though? or is it happening intermitently?

[lone_slayer]

a bit of both was starting fine but would run like crap for hillstarts etc was worse when warm sprayed some start ya bastard on the manifold and watched the revs change

[qazyy123]

Ok, thanks, sounds pretty similliar to mine. Except mine does rine fine sometimes when its warm, sometimes itl bog down for anything between a few seconds, and 20 minutes, then run perfectly fine for a while again. Have just checked the carb seals and managed to tighten them up a bit, so ill see how it runs tomorrow.

[qazyy123]

Ran sweet as, all the way to tech and back today. Then took it for one last ride this afternoon and its still doing it. have bought an ignition coil off trademe to see if thats the problem too.