Pinholes in exhaust - GS450L

[tthayer]

Once I got the bike idling I noticed something breezy on my toes and looked under the bike for the first time. I noticed a small hole in the cross-over pipe and another in the right-hand pipe just after the join. I realize that these spots will affect backpressure and want to get them repaired if necessary. Is there an easy fix or do I need to bring the pipes to an exhaust shop to get them patched?

[Steve]

Not sure about the crossover pipe, but there SHOULD be a small hole (about 2mm) under the front of each muffler.

It is there to drain any condensation that forms.

As long as the holes are not much larger than that, it will not affect "backpressure".

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[tthayer]

That is good news. The holes sure look like they're caused by rust but they aren't more than 2mm across.

[mike-s]

Steve, that "hole" your talking about is only on the header section of the pipes and is only a hole in the outer chromed layer of the pipe in order for moisture to have a place to drip out of when cold and to evaporate out of when the engine is started up. There is not a hole that goes all the way through the inner tube of the header, so no exhaust gasses should come out anywhere except from the tips at the back of the bike.

Also some exhausts have a similar moisture drain hole at the bottom fromt of the cannister. It doesn't affect the muffling qualities as it is behind various bits of metal and sound deadening materials but again gives a place for condensation to drip/evaporate out of.

That being said, some exhausts just do not have this breather hole whatsoever.

As to the holes, i would check the thickness of the metal. If it has gotten paper thin then that section will have to be either patched over if it is a localised thinning, or replaced in it's entirety if it's a section that has worn through. I have had an auto repair shop replace the mid section from the seam weld at the bottom of the front of the headers right through the mid pipe and right through to the muffler mounts as everything in between was shot. They also took apart my mufflers and cut out the 2 or 3 thinning holed/thinning bits and tigged on a couple of thin sheets of metal and sprayed it with exhaust high temp paint over the repair to seal it inside & out.

Cost me $160Australian about 6 or 7 years ago to have it done on my old bike and i left it with them for about 3 days for them to do as an in-between job when they had some down time from making some performance exhausts. If i had this happen again i would happily get these guys to get the repairs done. Any bandaging is only going to mask and temporarily mask the problem, which is what i did for my registration slip before i got these guys to do the repair.

[Steve]

Steve, that "hole" your talking about is only on the header section of the pipes and is only a hole in the outer chromed layer of the pipe in order for moisture to have a place to drip out of when cold and to evaporate out of when the engine is started up. There is not a hole that goes all the way through the inner tube of the header, so no exhaust gasses should come out anywhere except from the tips at the back of the bike.

Interesting.

The holes in my pipes are at the front of the mufflers, not too far from the weld. They go all the way in. When starting the bike in cold weather, you can see puffs of exhaust coming from the holes.

I have also seen this on more than one bike.

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