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Discussion Starter #1
I started my bike up this morning and noticed that, as well as exhaust fumes coming out of the back of the exhaust (as they should), they were also coming out of a hole on the underside of the exhaust, in exactly the same place, on each.

Is this normal, or am I about to foot a rather expensive bill for new exhausts?
 

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I've never heard of any type of forward hole or fresh air intake for an exhaust. That doesn't mean much though, I haven't heard of a lot of things :?

You say the holes are in exactly the same postion on each pipe. Do they look drilled or like they are suposed to be there? If they do I'd say not to worry aout it. If they are rough edged, then it may just be a common spot for condensation to rest and be rusting from the inside out.

Do you have exhaust restrictions or inspections there in the UK? Someone may have tried to be sneaky and add a touch of fresh air to them to lower the CO2 levels at the rear to pass?
Just guessing here??
 

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Discussion Starter #3
I doubt that the previous owner would have worried about emission tests, as it had its first MOT in March (I bought it in November).

The holes don't have rough edges, although that kind of thing is difficult to see when its wet, and I never noticed them before.

I'll have a look at the weekend when its light.
 

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vorlon24 said:
I doubt that the previous owner would have worried about emission tests, as it had its first MOT in March (I bought it in November).

The holes don't have rough edges, although that kind of thing is difficult to see when its wet, and I never noticed them before.

I'll have a look at the weekend when its light.
the GPZ500 is the non-US version of the EX500, which is what I have. I just replaced the factory pipes with some aftermarket full exhaust, if you are needing a replacement I'm sure I can make you a very sweet deal on the whole thing or just pieces of it. the right muffler is kinda scratched up, but if you just need the header/midpiece and no muffler then I've got what you need. e-mail is [email protected]
 

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Hi

Here in Germany lot of bikes have such a small hole (2-3mm ) at the beginning of the mufflers at the underside.

Has to do with "extra air" to let the exahust burn completely for better exahaust-gas limit or so.

Hands-on-experience:
If to much smoke comes out of these little hole, the mufflers are rust out inside or nearly blocked up.
If You block these holes You get backfires ( "bang, puff") if You close the throttle abruptly from higher engine-speed.

Sorry about my english, don't know the exact phrases.
Hope You understand what I am telling about.
 

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Yeah, there are drain holes on the bottom of the cans

Hi Vorlon24

There are holes in the bottom of mine just back from the start of the shiny steel (well it was once). I presume they are to allow condensation to drain out.

So unless they look really big and rusty (or make the exhaust a lot louder) I would chalk them down to it being cold and you had not noticed before.

I have been told that there is no emissions test as part of the MOT for bikes in the UK. Guess if I am in a bad mood next time mine fails you may find out I know different ;-)
 

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I have a GPZ550 and that was the first thing to rust out, was the lowest part in the exhaust on both sides, it sounds like we are talking about the same area.[/url]
 

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The holes just let condensation water out, that's all!! There are systems, that let air into the exhaust (newer bikes). The extra air allows any unspent fuel to be burned reducing emissions. There are certain reed valves that allows air to pass into the exhaust on deceleration. The air comes into the exhaust right after exhaust valve, not at the rear end of exhaust.

If you fill these holes at muffler you described, you will have problems with rust because of the water staying at the bottom of the exhaust. Eliminate this by keeping those holes open or drive longer trips to condensate that water out from the muffler.
 

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Exhaust difficulty GPZ500/84

Have a problem with my 84. Its a museum quality piece, 6000 original miles, never been wet. Stored in humidity controlled environment(family room). My exhaust cracked on both sides at the weld at pipe to megaphone. Same time. Seemed bizzare.

Oddly enough, the centerstand wacks the pipes by design....... So the welds on each side eventually gave way. A shame, since the machine was never choked above 1200 RPM and the pipes are as new today as they were when she rolled off the production line.

Am seeking an exhaust, factory stock, but have been un-succesfull in locating a set. Any help appreciated to keep her stock for life.
 

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PIPES

Check out OZ Cycle Salvage, Ottawa,KS. 785-242-0600 or their website...(only good for emails right now)...and tell Brad Peterson that Lindsey Angell from Gardner, KS said to give you the Kawasaki Forum Discount.
 

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Hi nelsonstansbury

Doesn't seem bizarre to me.
I assume You let the engine run from time to time for a short periode ( some minutes) ?

If You burn gasoline in an engine, You got water, Co2, some aromatic polycyclic hydrocarbon and sulphur as exhaust.

If the engine (and exhaust pipe) is cold, this mixture is condensing inside. Together with sulphur You got an agressive sulphur acid (H2SO4) which let rust every exhaust-pipe from inside, even those made of stainless steel (although stainless steel resists very much longer) ! :shock:
The only way to avoid such problems is always to let the engine run until the exhaust pipe is really hot till the end, so water and acid inside can evaporate completely.
If You start the engine only for some minutes or You go on short shopping-tours the exhaust pipe oxidize much quicker than if You take the bike on long tours !
Another drawback is that You got these exhaust-gas not only in the exhaust-pipe, also a small amount is bypassing the piston and accumulating in the engine oil! There You got the same problems (acid) after some time as with Your exhaust-pipe.
:arrow: Always avoid short distances, especially if You try to conserve Your bike. On the contrary: long tours and moderate revs will conserve !
Or You put the spark plugs out, put some motor-oil in and turn the back-wheel by hand from time to time (2nd gear) or kick (if kickstarter is existing) if You have the bike staying in a storage or so
 

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Hi Nelsonstansbury.

You don't say where you are in the world.

I seem to remember that the GT550 was in production until a few years ago.

If they are the same exhaust you should be able to get a GT550 one. I don't know if they are though.

Does anyone know if they are the same bike?
 

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