Lean-running GS500, all of a sudden?

[ClockworkJesu...]

Hey, so, I've a '98 GS500E with a '94 engine, if that makes any difference.

Anyway, she'd always been great on start-up, firing off the button with full choke whatever the weather. But recently she's been cranking over longer than usual.
So I ignored it for a bit, but today during a few basic checks, I whipped the sparkplugs out and they were white!

Last time I checked they were the sandy-cardboardy colour you'd expect. But for some reason the GS has started running lean?

I've got no idea what it could be. I've had a problem with fuel delivery in the past (Sometimes if I ragged it, usually in 5th, the bike would start to choke and splutter like it was running out of fuel, but, the tank's nowhere near empty. Fuel demand problem?) but it's not a constant, ever-present issue.
Dying sparkplugs not producing a bright enough spark? :S

[J.M.]

I can't comment on the cranking over (my only experiences with this before have been battery related) or the spark plugs.

[_Iain_]

Mine did exactly this.

Air leaks on the intake rubbers & clogged carbs.

Then for my hard work the engine turned itself into a case of metal filings...
____________________
Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340

[ClockworkJesu...]

That's a great bit of news. Thanks, J.M.

Doesn't look like Pingel make a fuel-tap for a GS500, but a 2004+ petcock should be easy enough to source.

[ClockworkJesu...]

[_Iain_]

Totally unrelated engine death - ran sweet as a nut after sorting the carbs/rubbers out.

Dont think it appreciated my attempt at beating paddys 120mph on a GS. Managed just over 110mph. On private roads obviously
____________________
Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340

[orac]

the fastest way to check if you have an intake leak is to get the thing warmed up and idling then spray the rubbers with WD40 or alike, if the revs change then you have a leak, if they stay the same, your rubber are more than likely fine.

after that strip clean and rebuild carbs, if they are both the same (plug colour that is) then it may well be a fuel issue. dont forget that the gs5 has 2 fuel tap, one on the bottom of the tank and a vacumm tap so check thing like vaccum hose.

also another thing to check while you are looking at carbs is float hights, if that are set wrong they will starve the engine of fuel.

alos check you have a strong spark, normally weak spark makes it over rich but it will be worth a check while you are there
____________________
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"

[ClockworkJesu...]

[orac]

doesnt have to be wd40, could be brake cleaner, intake cleaner or anything else that will burn. fuel line could be an issue if they are not the standard bore, dont forget suzuki made them that size for a reason
____________________
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"

[ClockworkJesu...]

Alright, good info.

Thanks. Think I'll make my way through the list before looking for some standard fuel-lines. Which have always alluded me. :S

[_Iain_]

Spray the rubbers with Easy start. Worked a treat to find my leaks - the wd40 wasnt as noticeable & made a mess.

Texaco also sell easy start & its good at cleaning carbs too
____________________
Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340

[ClockworkJesu...]

[ClockworkJesu...]

Well, I got the engine warm and ticking over, a little lumpy but ticking over, and sprayed some chain cleaner between the carbs and the rubbers. Nothing.
Sprayed some chain-cleaner between the rubbers and the head; revs rose for about a second and smoothed out, and then dropped back to their lumpy selves.

Looks like leaky rubbers! Thinking a bit of high-temp silicon behind the rubbers might sort things out.