My GS is hissing.. yikes!!!

[vtlion]

Hey experts,

This may be a little premature... I haven't really had a chance to inspect the problem in daylight, but I'm concerned, so I'm gonna toss it up on the board for comments.

Today my GS started making a very slight hissing noise, like gas escaping from a crack or a gap.  The noise seems to get louder in proportion to RPM's...  if I clutch it, (and RPM's fall while speed stays the same) the noise seems to go away.  The bike runs/performs perfectly except for the noise... no noticeable loss of compression or anything like that.  The best estimate that I can give for the location of the sound is somewhere up in front of the combustion chambers, but being that the bike has to be running for me to observe the problem, I can't be sure... its pretty noisy up there by the engine.  But I can hear it best while moving when I lean my head down near the instruments.

My first thought is an exhaust leak.

any ideas or advice on how to proceed?

thanks in advance to the experts for savin' my bacon yet again!!!     THIS BOARD RULES!!

peace

[glenn9171]

I got a nickel that says it's loose header bolts.

[yamahonkawazuki]

i second the header bolts, mine leaks, (and occ. fouls plugs on 1 side), i tightened it up, it also hissed,  and the tightening up, got rid of the noticeable hissing

[vtlion]

I don't have a manual (maybe now would be a good time to buy one ) and I'm about the least engine-savvy person I know... spell it out for me guys...

where exactly are the header bolts?

[Lars]

It's the bolts that hold the exhaust pipe on the engine. There are four of them, they are generally rusty and if  you're lucky they're not seized.  

On my engine they vibrate loose after some time.  check if there's one or more missing or if they are loose.

Good luck  

[Briliu]

i completly lost one of those bolts about 3 days ago. I get home and i notice its ALOT louder than it was before. So i look down there and i see that 1 side has 2 bolts and the other has 2, UH OH.

Before it completly came out i noticed a wierd sound. I guess you could describe it as hissing, it wasnt constant though, then when the bolt came out it sounded like a freakin monster when i reved up.

All fixed now!! Good luck with fixing that!

[vtlion]

anybody know off hand what size hex-key those header bolts take?  I think I need to make a run to Lowes for some tools.

I gave them a look-see this morning and they were hand-tight at least.  I guess it wouldn't take much of a leak to make that sound though.  

peace

[Rashad]

Either a 5or 6... or was it 7?

i think 6...

[vtlion]

hey folks... I totally lucked out and had the right sized hex-key at the house.

All 4 bolts turned fine and all of them were tight.  The noise is just loud enough that I'm convinced I'm not imagining it.. what's next?

seals?  hairline cracks?  I'm really confused, and afraid to go road trippin' with this condition, but the weather is PRIMO!! the clock is ticking... what should I do?

peace

[tmc008]

it's a six

go to sears and get a 6mm hex socket, it makes it a hell of a lot easier

just a suggestion, of course

and if you lose these go to a bolt, screw, type store with one, and they'll sell you some nice ones that are only about .53 a piece. and i also suggest changing them once every few years. i work on hmmwv's and in my shop it is standard to replace them anytime we touch them. just another suggestion. enough.