gs450L fuel prob overflow into airbox

[prxbadger]

hi, cool site, hope you can help

i have just bought a gs450l because i liked the look of it and have owned a very heavy bike for a long time

the problems are

the fuel tap allows fuel to pass in res/prime/on positions

after 10 seconds of running fuel begins to pour from the airbox overflow

the plug on one cylinder was very damp

the air filter seemed very oiled up

i assumed it was a fuel problem but as the carb itself wasnt overflowing despite a constant flow of fuel even when the engine was off, i was at a loss

i changed the air filter and plugs and now after 10 seconds the same problem and also gets hot and sluggish eventually dying

this time i noticed the plugs were blackened and dry


any help would be appreciated, the exhaust is the original and i havent touched the carbs yet


thanks

[chronoman]

It must be the needle on the carbs sticking, i bet if you set the fuel tap to prime it will leak even with the bike not running.

Clean the carbs, check your intank fuel filter, change oil.
Mine was doing the same thing when I bought it. again make sure to change the oil once you fix the carbs.

[prxbadger]

hi, i charged the battery and noticed the tap was set to prime, it no longer leaks from the air box but im getting poor performance at high revs

maybe mixture setting after changing the filter

[Dave8338]

the problems are

the fuel tap allows fuel to pass in res/prime/on positions

after 10 seconds of running fuel begins to pour from the airbox overflow

the plug on one cylinder was very damp

any help would be appreciated, the exhaust is the original and i havent touched the carbs yet


thanks

Sounds as though you have a combination of problems. 1st, the petcock with the prime position should be vacuum actuated. It should only flow in the PRIME position. (if the bike is not running) When the bike is running and applying vacuum, it will flow in all positions. Also, It sounds as if you have one needle/seat combo in the carb that corresponds with the wet plug, letting fuel past the seat. New petcock and a good carb cleaning (maybe a new float needle) and you'll be back in business! \\/

[rkubik]

bowl vents

When mine was flooding gas out the airbox, it was because I had incorrectly installed the carb bowl vent hoses. Once I took off the hoses and left the bolws vented to the atmosphere, the problem stopped.

[prxbadger]

hmmm ok, will have a look, mine has mysteriously stopped now, its seems to be running ok, it ticks over cleanly when warm, revs ok when standing

but........

when riding it struggles at 4k rpm, it still accelerates but is pretty lumpy

hoping the previous owner didnt run it with the oil in poor condition

[nabrams]

Your vacuum line may be sucking fuel - see other posts

[prxbadger]

cheers abrahms will check, have looked previously and seen a fine mist coming from the pipe end that the hose attaches to on the carb inlet, while the engine was running

gonna try some redex petrol treatment rather than sync the carbs too as it idles very nicely