Idling rpm's all over the place

[Hoges]

My idle won't hold steady rpm's and needs a constant blip of the throttle to stop it from dying at idle. When I do this but, it goes up to about 2000rpm's for a sec or two before dropping back to less than 1000rpm's and then falling away to stall. Its a GSX750SE and am thinking it's an air leak maybe. All the boots are snug and tight with nothing visible being wrong. I've been playing around with the mixture screws and at the moment seems best at 2 turns out. Any help or advice would be welcome, cause it's making city riding a nightmare.

[almarconi]

Get a can of carb cleaner or WD40 and spray the carb boots. If you get a change in RPM then you have a leak.

When was the last time you cleaned the carbs?

Also check your throttle cable, if it is binding or not adjusted properly the engine RPM's will be all over the place.

[Hoges]

Sprayed WD40 onto the carb inlets and no change in rpm's. Have cleaned carbs 500 miles ago so should be okay. I've just taken the air filter out to see if that makes a difference, so will give it a run. Plugs all look okay as well.

[chef1366]

Is it the sixteen valve?

[Hoges]

Yeh Chef, it's a 16valve motor, and I only did the valve clearances last month. I know its not much, but its bloody annoying. Little bit of a miss at low revs (2000rpm) as well, so I'm thinking its a mix problem. Its good this site for new ideas when tracing similar probs.

[psyguy]

Is it the sixteen valve?

hey chef, a gsX always indicates a 16v engine - as marketed outside the usa

[Hoges]

I didn't know that either actually...

[psyguy]

for me it was actually the other way around...
i never knew that the usa 16v models were NOT called gsX until i joined this forum - lol
europe, the uk, and "down under" - all have the gsx denomination


oh, btw, id say you have a very lean condition and/or an intake leak

[Suzuki_Don]

get your idle mixture screws right. They are too lean.

[chef1366]

Dirty pilot air jets, pilot jets, idle mixture screw o-ring bad or maladjusted.

[Hoges]

Thanks for the replies on this one. Mixture screws std at 2 and 1/4 turns out,so to richen it out do I turn it out??

[chef1366]

Yes, out to richen.

[Hoges]

Thanks again chef, hard when you look at life from upside down hehehehe.

Rob.

[chef1366]

Depends on where you're at when viewing it.

[Smokinapankake]

Is this the Pop Up headlight GSX 750 SE (otherwise known as a Katana 2)?