Petrol from the Idle Screw breather hole

[cubeblock]

I have an old GSX750F which has been standing for about a year after I bought it. I have just got round to getting it back together. The engine would only run on choke before and I have just replaced the rusted cable. I can't get it to idle. The engine runs ok on the center stand and keeps constant revs with a little bit of throttle but I can't get it to just tick over. Whilst I was adjusting the idle screw I noticed some petrol drippig from the breather hole. Does anyone know whats caused this?

Thanks

[The CyberPoet]

Probably bad O-rings within the carbs (such as the ones in the feeder fuel rail at the connections). When they sit empty too long, esp. on an older bike, they tend to crack and fail.

Cheers,
=-= The CyberPoet

[md86]

And after sitting for a year and not wanting to idle ..... look for the thread about cleaning your carbs . I bet you need it . Now what is the "breather hole" ? Not sure I follow that one .... But I'm GUESSING you mean a part of the airbox . IN which case , I'd say stuck float or worn o-rings in the float assembly . Oil level go up and does it smell like gas ? If it does , don't run the bike until you change the oil .....

[cubeblock]

I have looked in the manual and I can't find out what the right term for the breather hole is either but underneath where the idle speed adjusting screw goes is a small airhole. I guesss as you turn the screw in and out it alters the air mixture. Its from this hole that I have the petrol dripping.

[md86]

Wait , the idle adjuster doesn't control the mixture , but the little screws under the carbs DO , and they could leak if the o-rings in there are worn ..... Any chance you can point out where it's leaking from on the parts diagram ?

http://www.ronayers.com/fiche/300_0057/carburetor/carburetor.cfm?man=su&groupid=5140&parent=5030

[cubeblock]

The picture is taken from the right handside of the bike looking up at the end carb. You should be able to make out the idle screw which is a copper colour at the bottom of the carb. I have circled in red where the hole in the bottom of the carb is and a droplet of petrol can be seen there.

[Court93kat]

Ok... now we're getting somewhere. That is not your idle adjustment screw. That is the carb bowl drain screw. You loosen that to drain the fuel out of the bowls. If you have loosened that.... tighten it back up and let us know if it still drips.

There is an o-ring on that screw, and it might need to be replaced if it still leaks.

[md86]

Or maybe some ape over-tightened the screw and knackered it up . Easy enough to see . Try to tighten it JUST a bit . If it's already tight and still leaking , gotta pull it off and see WHY . Not too hard , really .

[cubeblock]

Thanks, I appreciate the help on this. I bought the bike to learn a bit about basic mechanics on these bikes and as you can tell I have away to go still [/quote]

[md86]

Buy a manual , and get some decent tools .

[cubeblock]

Got a Haynes manual but I didn't read up on this bit. For some reason I got it fixed in my head that it was the idle screw which is on the left handside of the bike I was hoping to get the workshop manual from this site but it doesn't seem to be available at the moment.