weird backfiring all of a sudden

[defwack]

As of today, my 1980 GS850G is making a wierd backfiring noise. It sounds high-pitched, almost like it's got a bit of a whistle to it. I just changed the oil and filter yesterday, so could that be causing this? It seems to be coming out of the left side only.

[carlosjc401]

air

sounds like an air leak

[83'GK]

Headgasket letting go....

[defwack]

The head gasket looks good, and there's not even any seepage coming from it. I don't know much about the mechanical stuff though, so it could be that and I can't see it.

I just went and took it around the block, and the sound only seems to happen when I'm slowing down or idling. It sounds like a backfire, but not quite. It's not as deep or booming as that, and actually it's quite high-pitched and sudden.

If you ever listen to mp3 music, it sounds like when an mp3 "skips" and that's the best way I can describe it.

As for the air leak... what is that and is there anything I can do to fix it?

[katoranger]

Check the exhuast over for holes. He is referring to an airleak on the exhuast system. It may be at the header gasket. An air leak will cause a backfire on decel.

Allen

[defwack]

What about a hole in the exhaust under the bike? I did notice a small hole right around where the H-shaped exhaust connector is under there. That's also kind of where it sounds like the noise is coming from.

Can I repair that easily, and will it cause damage to the bike when it pops like that?

[RotaryRodder]

mine has popped before, I have holes in the exhaust. Since the weather has gotten warm it has gotten worse. I think its just something ill have to deal with untill I fix my exhaust and adjust the valves.

[katoranger]

That could be your problem. If they are small you may be able to seal it with JB weld or exhaust putty. JB Weld runs about $6 at Walmart.

My old virago had straight pipes that would make it pop on decel. With the holes down there that is essentially what you have.

Allen

[defwack]

Thanks for the input. I'm going to clean it all up and take a good look down there tomorrow. It just surprized me how sharp and loud that noise was... sounds like a bottle-rocket firecracker going off. I thought a piston was about to come shooting up through the gas tank the first time I heard it!

[katoranger]

That is an exhaust leak for sure. Take a good look and try to seal it all up. I have made patches from tin cans and used JB weld to glue them on. Some tape to hold it while it sets up it a must. There is also JB Quick which is 5 minute weld. The other stuffs needs 24 hours to cure.

You may find that the entire crossover is rusted out.

Allen

[katoranger]

This thread may apply to your bike condition.

http://www.thegsresources.com/_forum/showthread.php?t=89837

[defwack]

Just out of curiosity, what causes the noise when it backfires like that? I mean, how does a hole in the pipe cause it to do that?