fuel hoses on gs450L

[Anonymous]

all of a sudden my 80 gs450L has started running like its not getting gas, its doing it right now for the second time ever, it only does this when its cold and first time fired up for the day after being run the day/night before,

there are two hoses coming off the petcock assembly on the tank, one is larger than the other, i pulled the smaller one off at the left carb and no gas comes out at all, shouldnt it come out gravity forced ?

tank is full to the top top as much as will go in it, the smaller hose i replaced about a month ago, the last time it did this was two days ago, it wont rev up very fast at all is a huge delay in rev up bog then up after a few secopnds, almost dies when i open the throttle and choking it doesnt help, and now and then a backfire,

the other day when it did this i put the valve over to reserve and it immediately cleared up like nothing ever happeend


id say petcock is going screwy ?

drill the stupid thing out ?

remove it from tank and dissassemble it ?

smaller hose for LH carb should be running gas out right?
i just heard that the smaller one might be vacuum ?
it only runs from the petcock down to the LH carb so how can be connected to any vacuum source ? when does the bike need this ???



thanks

 

[Anonymous]

Fuel hoses

Fuel hoses

Your petcock(fuel tap) is operated by vacuum from the carbs,so keep the smaller pipe connected.It may be the integral filter on the tap is blocked or damaged so take the tap off and have a look.While it's off you are as well to strip the tap and check that all the internal passages are clear,maybe a bit crap has got through the filter and partially blocked something.Your manual should show how to strip it but if not (assuming yours is similar to the 550) here's how.With the tap off the tank remove the four small crosshead screws on the plate behind the lever and lift off.There should be a thin spring washer on the body of the lever so remove this also.It goes without saying don't lose it!The lever body can now be lifted out and the petcock body can be separated,revealing the valve diaphragm.Clean out all passages in the components and check the condition of all o-rings and seals.Reassembly is the reverse of the above.Hopefully this should help but if not you could run with the tap on reserve keeping a close eye on your fuel level.

 

[Anonymous]

awesome, i appreciate it, i am going to remove my tank in a minute out here and dump it out and take apart the petcock and clean it out and all that and also clean electrical connections for coils and such becaus ei just pulled the plugs and my right plug is wet and my left plug is dry but smells like fuel a little in the cylinder

sooo i think it might actually be spark problem,

idle is really abnormally low and the idle has speed up spike in it every couple or three seconds now and then, sometimes the idle spikes up twice in a row real quick, its not running right this is the secodn time its doen this in the last coupel days its never doen anythhing like this before, it ran fine very strong always, and did last night too, when it did this a few days ago i moved my tank to prime and it immediately cleared up and ran strong like always, so i put gas in it and put it back to normal position with no change at all, still ran great, but now this AM when i fired it up it was running like junk again for now reason, bog on acceleration, very slow response, and horribly low idle speed with real quick speed up spikes, not a regular pattern, are random spikes

something must be loose or corroded at a coil or something,.,.,
'
right?

thanks

 

[Anonymous]

i just removed the fuel tank and i put the petcock on prime and billions of gas come out ot the larger hose so thats good

so i put it back on on position and just barely sucke don the vacuum hose and billions of gas comes out of the larger hos,e so thats fine too

billions= TONS

sooooooo...........

that rules out faulty or clogged petcock, its still stock original one works great, easy to move between positions

i consider it to be a magical rare petcock with it being original and working great

isnt it ? sounds like it right?

from what i have researched on this board it all seems great as far as the petcock on this tank of mine goes,.


moving to primary coils circuits and electrical connections now, IE moving into uncharted territory i have no clue how bike coils circuits are wired or work, i am very mechanically inclined and only know how car and truck coil primary and secondary circuits work and are wired

anything anyone can share with me aspa would be greatly appreciated, so that i might not blow something up in my ignitions system ??

oh and do i have points or ?
i have a some kind of ignition trigger box made of aluminum under my side cover, what is this thing ?

thanks

 

[Anonymous]

Fuel hoses

Fuel hoses

Yeah,it's worth checking and cleaning connectors in the ignition circuit.Check for a spark at each plug by removing it from the head and grounding it against the engine.Make sure it is grounded 'cos you can fry electronic ignition if it ain't.If your getting a good spark at both mebbe try stripping and cleaning the carbs,making sure the float heights are set correctly and are identical.Sorry I can't be of more help but these things are a nightmare,been there,done that.You have my sympathy.Good luck!

 

[Anonymous]

Re: Fuel hoses

Re: Fuel hoses

Yeah,it's worth checking and cleaning connectors in the ignition circuit.Check for a spark at each plug by removing it from the head and grounding it against the engine.Make sure it is grounded 'cos you can fry electronic ignition if it ain't.If your getting a good spark at both mebbe try stripping and cleaning the carbs,making sure the float heights are set correctly and are identical.Sorry I can't be of more help but these things are a nightmare,been there,done that.You have my sympathy.Good luck!

yep i just got done cleaning all 12v connections with WD40 and i checked secondary output with the plug that wasnt soaked and its got great white spark snap snap snap very audible, so,, hmm

im stumped,

would the right side carb just act up and put out too much fuel out of the blue for no reason ?

what would be culprit ?

i dont know what else it could be,
this happened one day a few days ago and after i put it on reserve it came right out of it instantly and was great until this AM cold start, runs like junk now, bog on acclerate, spikes in idle;

humm.,.

wierd.,,.

im gonna start it up after i drain the bowls and compare fuel volumes from both, and tap on the carbs with metallic object carefully


can a dirt piece in a carb cause wet plug somehow ??

otherwise im lost now,.


thanks for your time and reply info

 

[Anonymous]

Fuel hoses

Fuel hoses

Yes,all it needs is a bit dirt in the float valve to stop it closing properly,but then you'd get gas out the overflow pipe.Really starting to sound like you've got a wrong float height.If it's set too low the float bowl will have too much gas in it and you'll run rich causing a wet plug in extreme circumstances.Too high and there won't be enough gas causing lean running an overheating.Take your carbs off,drain them,remove the float bowls,invert them and,keeping them level,measure from the bowl gasket to the top of the float.Not sure what yours should be but try 22-24 mm.
Make sure they are both equal.If either measurement is less than 22mm with the gasket in you'll be flooding the carb.Haynes do a carb manual which I've found invaluable as carburation really is a black art! :?
http://www.haynes.com/na401.html#anchor1228398
Once again,good luck!

 

[Anonymous]

cool thanks


welp i started the bike up and my RH exhaust pipe is not getting hot and every now and then the RH cylinder will KABOOM bang out the exhaust pipe, the plug is wet and top of piston is too,.

this happened out of the blue it always ran perfectly fine til now, a good clean stock bike, the plugs i just bought two weeks ago, i replaced them for no reason really, with same number brand plugs as what was in it, in which showed to be correct at the parts store.



what do i do ?
i really hate to have to remove the carbs it is a PITA to remove them,

my RH fuel bowl had less fuel in the bowl than the LH one, the LH cylinder runs great.

also do the idle air mix screws richen or lean mix when they are screwed in or out ? do you adjust for max idle with them by turning them inwards or outwards ?


thanks

 

[bgmart450]

Ummmmm.... I have my hoses reversed, I think they been like that since I got it. I never would have noticed except my wife's 450 is identical and it stands out when they aren't exactly the same, any reason it would matter? As far as I can tell my bike is running pretty good, any reason I should worry?

 

[Anonymous]

ok originally RH exhaust was not anywhere near even close ot as hot as the LH pipe so i swapped the two spark plugs and now the LH pipe is not getting hot, the plugs are like three weeks old

faulty denso plug ?? the bike idles ok and revs ok not under load but damn when you try to evne take off in first it dies splat, no power at all i think my 3.5 horse push mower could take off better than that if it were mounted in the bike chassis

im like 75% sure im running only one cylinder since one pipe is barely just warm and other is damn hot.

the plug thats making cold pipe is the one thats been wet as heck


i tried heating it dry over the stove..


what do you think ?
be something as reta4r5ded as a faulty plug ??
is Denso brand POS or something ?
maybe the plugs are not hot enough heat range ??

is that bad or something ?

 

[Anonymous]

Fuel hoses........

Fuel hoses........

It could be something as simple as a duff plug.If you've still got the old ones put them back in and see what happens.I've had probs with Densos
in the past,and I use NGKs now.I tried Splitfires and my 550 hated them,wouldn't run worth a sh*t. Put the NGKs in and off she went.Definitely try a new plug.

 

[Anonymous]

so Denso have issues ?

hmm i hope i still have the old ones around,,

humm..

thanks

 

[Anonymous]

WD24ESR-U is what was in it
and WD27ES-U is whats in it now, i replaced the 27ES thats wet with a 24ESR i still had,

it is still not burnign fuel with the old plug that it ran fine with before i bought new plugs a few weeks back

which plug number is correct for 80 gs450L ??

the RH cylinder now doesnt wet up, now its the LH one doing it, and evne no mnatter which plug number i put in it what gives ??


is this just a denso plug thing ??

 

[earlfor]

When a cylinder is running wet and you can swap plugs around and the cylinder runs normal, then the plugs are the immediate problem. However, if the mixtures and float heights were correct in the first place, you wouldnt have the problem at all. To tune the bike properly and accurately, all cylinders must be firing. You will have to remove the carbs and set the floats to the correct heights. You have already said you bowls have different amounts of fuel, so you know they are set up wrong. Fix it. You dont have a choice. 1980 should be CV carbs (constant vacuum) and those do not have separate air and fuel pilot adjustments. The adjustment you have is a mixture screw. Pilot fuel and air is already combined and the screw regulates how much mixture you get. Turning the screw out richens and turning it in leans. However, you cannot set mixture precisely without knowing what the intake vacuum level is because idle rpm requires a specific intake velocity for the jets to meter the correct amount of fuel.
This is also contingent on the float height. Everything is inter-related, so you must tune the system, not just change an adjustment here and there by guess..............if you want the bike to run right.

There is nothing wrong with NGK plugs, they are not the cause of your problems. Set the float height. Install new plugs. Start the bike and let it warm up until it will idle without choke. Set the throttle plate position so that you have 10 in Hg @ 1200 idle rpm. Then set the mixture screw to allow the highest rpm. Then turn the idle adjustment knob so the engine is again running at 1200 rpm. Reset the throttle plates to 10 in Hg vacuum at that rpm.


Earl

so Denso have issues ?

hmm i hope i still have the old ones around,,

humm..

thanks

 

[Anonymous]

yeah im having problem of one cylinder not burnign fuel with one plug but burning fine with another,

this bike ALWAYS ran perfect every day no matter what just til last couple few days, just all of a sudden poof it started backfiring now and then and has half the power it used ot have and makes looooong delay in throttlew response, dies when trying to take off just in first even, just wont do it,.

this was a great running reliable daily driver

i dont know how to do this carb stuff, i dont knwo why it needs it out of the blue for no reason, i dont know why.,

i cant do carb stuff not on bikes and i cantg afford ot pay to have it done, i can do a 4bbl rochester and carter quadrajet 4MV and 4GC and so forth and and rochester dual jet 2MV's and so forth and rochester and carter 1 bbl carbs but not any bike carbs, i dont have the tools or know anything about how they work ?

so ami toast ?

if so then im parting the bike i guess

apparently it doesnt want to be ridden ever again

it was a great looking running bike not a single issue ever,


hum

thanks for your time i appreciate

its over now, i cant do anything for the bike cept part it and scrap whats left, i dont have the resources to do whatever it needs now,

i guess i got my $600 worth out of it by having and riding it for a year now

maybe i will just light it on fire after removing the fuel tank again, and say "good riddance" and then scrap it, i dunno,., ill talk to the neighbor, he scraps stuff all the time,

 

[earlfor]

What a waste, when the problem is so simple.

Earl

thanks for your time i appreciate

its over now, i cant do anything for the bike cept part it and scrap whats left, i dont have the resources to do whatever it needs now,

 

[Anonymous]

ok sorry i apologize for my reply, i got frustrated thinking about how it might be a bigger problem than could be possible on a great strong running reliable bike

cuz see now,., the bike runs again like it always ran, and that is the following: damn good and strong!

what did i do in order to have it running back tip top shape again ?

i put in a new unused AC Delco R44XLMS6 plug that i had laying around, same threads, reach, length, seat, and everythng cept that the top is the large style slip on nipple and it needs to be the skinny threaded nipple,

runs GOOD, strong very quick throttle response and rev up all way to red line

going for a ride, bbl with report

if all goes well then i am never buying denso plug in my life again, i wil consider them B.S.
thanks

 

[Anonymous]

all better, no issues at all now, now its all like it never happened, actually seems to have a bit more low end torqe now than it ever had.

hmm..


thanks i appreciate everyones replies and time
r

 

[Anonymous]

update again:

started up the bike for the first time today just now and it started right up and runs strong, not any issues at all.

thanks
randy

 

[Anonymous]

Fuel hoses

Fuel hoses

Glad you got it sorted,bro! :wink: