My Shiny Exhaust (s) are becoming Discoloured and What about cleaning the Exhaust?
For Performance-Related Items with Exhaust and Opinions on Exhausts see the Performance Mods FAQ
For Exhaust Gasket Replacement and Exhaust Nuts or Studs see that FAQ
What about that little Cylinder in the Airbox – What’s that ?
Flash #412 & Marty #436
December ‘01
The colour of the smoke tells you what the source of a problem with your Engine could be.
Crude oil is comprised of ALL fractions cracked by the distillation process. If you burn highway or roof asphalt, does the smoke it gives of as it burns the same color as lamp oil? Both fractions are contained in crude.
Over-rich mixtures burn black. Ever look at a spark plug from a motor jetted way too-rich?
A motor with bad valve guides and/or rings gives off blue.
White is indicative of water loose in the system. What color is the tailpipe emission from a car when it is first started on a cold day, as the condensation exits?
Assuming that you are using antifreeze in the radiator (and not straight water), the glycol in it has a distinctive sweet smell after it passes out through the exhaust pipe (same smell as when an engine overheats and "spews" coolant).
As others have said, the water/condensation makes "white" (scent-less) smoke, rich fuel mixture makes "black" smoke, and oil makes "blue" smoke. I had the head gasket on a Mitsubishi pickup fail, making the white, sweet smoke. Disassembly showed the head gasket had failed between the cooling jacket and a cylinder. Other modes of head gasket failure can also allow oil passages to leak into the cooling jacket (or vice-versa?) or the oil passages to leak into cylinder.
Bob#550, David#476
Occasionally the Foil Heatshield protecting the Side Cover from the Exhaust Peels off.
The foil heat shield should not be glued back to the bike's frame.
It should be glued back onto the plastic cover where it fell off.
3M makes a weather-stripping adhesive that works well for this purpose, sometimes referred to as "gorilla snot."
Another 3M heavy duty spray adhesive worked pretty well, too.
3M Spray 77 is the product Bob refers too. If it's N/A where you are, any adhesive that is applied by putting it on BOTH surfaces, allowing it to become tacky, then reapplying and sticking it together will work. The point being no adhesive (e.g. the one they use at the factory!) will stick the fiber to the plastic, you need to use one that the adhesive sticks to itself.
Other ways of getting rid of the Heat
David#476, Harl #380, XXX, Randy #478
December '01
The exhaust heatshield got me to thinking about exhaust heat and its effects on the motorcycle and rider's "parts". Besides the stock heatshield foil that prevent the body panels from melting, has anyone tried an exhaust wrap or any other heat management devices? (heatshieldproducts.com) The exhaust pipe snakes near the shock, airbox, etc. radiates a large amount of heat that gets absorbed by these parts. Of course this heat has no beneficial effects except maybe in winter. I'm curious if anyone has any experience with wrapping the exhaust from past the header under the tank to where it/they hit the can/s, in other words, the section directly under the rider. According to the info on the webpage above, wrapping the pipe/s will increase exhaust gas velocity (maybe more power) and decrease radiant heat in the area that is wrapped but wouldn't that also redirect some of that heat to the can/s and heat up the tail-section?
My experience is limited with the wrap and it's on sportbikes. However, a section near the battery would certainly help keep the electrolyte from evaporating, a problem on the pre-GS versions of the bike.
Your best alternative is an aftermarket muffler, which will eliminate a ton of the heat. The stock cat/muffler arrangement on the older 650's is a real heat sink! I put the Staintune on and heat problems were solved.
No personal experience, but from what I've read, wraps do everything mentioned here AND wear the pipes out faster. Supposedly "JetHot Coating" has all the benefits as well as EXTENDING the life of header pipes, and has the added benefit of trick colors. One fellow who JHCed his Triumph header pipes noted a 10°-15° drop in external temp. From what I gathered, the excess heat (that the wrap hold in) heats the metal of the pipe higher each time it's run. Bottom line is that it fatigues the metal faster causing it to become brittle sooner. Keep in mind, too that we're talking about racing headers which, for weight reasons, use minimal wall thickness. On the metal of our pipes it may be a moot point. The JHC, OTOH, puts a thin ceramic coating on the INSIDE as well as the outside, so it insulates the PIPE as well as the surrounding components. The excess heat goes out the exhaust.
Dunno how much cooler the battery with the wrap would be. The wrap would probably need periodic replacement, as road splash would take its toll. I've heard of the wrap shortening the life on titanium pipes, but not stainless. BTW, it stinks for a while after it's put on the pipes.
My Shiny Exhaust (s) are becoming Discoloured
For the GS you should first read the Exhaust Modifications GS FAQ (General Questions) to see how the Two Canisters Work and what is inside them!
Rusty Exhausts
Bryan #179, Flash #412
Typical Question: My 2001 F650GS exhaust cannister's look awful! They are badly discoloured. My dealer says that BMW will not warranty this defect in materials? The stainless steel apparently discolours when the bike is ridden hard. Has anyone else had a similar problem and has your BMW dealer been able to replace the discoloured cannister with new ones?
The discoloured cannisters are signs of hard riding. Wear them with PRIDE!
Or you can get SS100 Color Restorer and spend 1-2 hours a week polishing them back to the original color. Like the ad says: "I just wash mine!"
A short metallurgy lesson: The chromium and nickel in stainless steel oxidizes when exposed to oxygen at high temperatures. This oxide coating is continuous, and protects the underlying metal from corrosion. In some steels, the oxide coating takes on a characteristic color, often gold, often blue - it depends on the alloy, the temperature the oxide was formed at, and a few other things. I find it odd that you consider this a defect in materials. It isn't. It's how stainless steel works. You can polish off the oxide, but it will just come back. I certainly can't see BMW replacing the muffler - the pipe operates properly. You'd only get one made of the same material, and it would do exactly the same thing.
The process by which the exterior surface atoms combine with oxygen from the air to form an impermeable barrier is called "passivation." Passivation is a specific form of oxidation. Aluminum passivates. You can rub the "dull" off of aluminum and it will passivate to a depth of two or three atoms. You can repeat forever. Or you can get used to it. Stainless steel does the same sort of thing, as Bryan pointed out. Part of what makes the difference in "color" is the depth of penetration of the oxidation. I've got a chart somewhere of the number of angstroms various passivation depths have to produce corresponding wavelengths (colors) of light. Stainless pipes that are chrome colored indicate you either rub more than you ride or else don't hardly ride worth a damn when you do. Back in the airhead[1] days, I once heard from some young German fellows that the ladies in the clubs there would not consider going for a ride with a guy unless his pipes were blued past the footpegs.
Stainless steel is made in grades, 314 grade is more prone to its appearance looking corroded/rusted etc than say 316 marine grade stainless. There are many other grades. So......not sure what grade the exhaust is made from on the bikes. I would say its only a cosmetic thing, it will not physically corrode or rust through.......at least for a very long time. Jack F650GS, Australia.
So don't worry about it.
For Cleaning your Exhausts, see What about cleaning the Exhaust.
For the GS you should first read the Exhaust Modifications GS FAQ (General Questions) to see how the Two Canisters Work and what is inside them!
Just became a member as I have purchased my first BMW; an 02 titanium blue GS (new to me with 5750km on the odometer). I am now waiting for the snow and salt to clear so I can take it out of the garage (believe me, snow in Southern Ontario in April is not the norm!). One reason this bike made it to the top of my short list is because of this forum. Very useful and often entertaining. My first message here has to do with the exhaust canisters: the left canister still has that new silvery look to it, while the right one is taking on an antique brassy glow. Is this normal? I also notice that while idling most exhaust fumes exit the right (hence the colouration?). Will the difference between the colour of the two canisters continue to grow? '02 F650GS, Ontario, Canada.
Discoloration of one is normal. Don't worry about it, enjoy the ride(s). Ted in TO, 01 GS
If the cannisters are not exhausting somewhat equally I believe there is a problem or potential problem. Those cannisters (or more specifically the one on the right) is not there purely for cosmetics cause exhaust comes out of it. The exhaust gas from the left cannister doesn't just make a right angle turn when it gets to the crossover so it was engineered. The exhaust and coloration are symptoms. I still don't understand a dual exhaust on a single cylinder M/C. My 01 GS has over 7000 miles on it and both exhaust canisters are "shiny silver" - no discoloration. Also, early on I stuck my hand behind the exhaust's while running just to see if they were close to equal and they were. county '01 F650GSA. Memphis, TN.
Me either! Shiny......, equal. No problems. Art 884
Chrome turns blue, stainless steel turns "antique brass". It can be polished off, but I prefer riding to shining. David #476, '99 F650.
I
know they both kick out exhaust - there's some kind of closed loop thing that
opens up above 4500RPM, and I believe that's when the left (as you're behind the
bike looking at them) can starts spewing largest quantities of exhaust. When I
have the bike idling, the right can kicks out what seems to be about 80% of the
exhaust, while the right can kicks out the remaining 20%. I haven't studied the
exhaust system too much so I can't intelligently speak to the purpose of the
dual cans, but I'm thinking (which is usually a dangerous thing for me to do)
that they could have done the whole job with 1 exhaust pipe/can, they just
thought it looked cooler if they had 2 cans.
Seacuke, #1214, F650GS, California, East of the Bay Area.
Sept. '01, I sold my 1400 Intruder to a friend. I did not see the bike again
until last summer
and was amazed that the first 3rd of the chrome pipes were dark blue. They were
never blue for the 5 years I rode it. He said he runs up the revs before each
shift which must be what made the difference. So....., different riding styles =
different colored pipes. Art 884
The left can is the catalytic converter. Some exhaust exits there, most crosses over from there to the right can which is the muffler. Look underneath and you'll see the crossover pipe. It is a single exhaust system, not dual. The entire exhaust system will discolor over time, it is nothing to be concerned about. My Japanese bikes came with dual-walled pipes so the outer wall never discolors, technology lost with BMW, just like self-cancelling turn signals. '01 Dakar -- Nashville. SScratch
Very Few
Problems with this. The Exhaust is Stainless.
I've got an '03
Dakar. Bought it at the end of September and have put about 9k miles on it. I
expected the exhaust to blue and bronze some, but my pipes are rusting. All
around the manifold is rusting, and the underside of the pipes and cans are
rusting. I do not live near the ocean, and I have been pretty good about rinsing
dirt and crud off the bike.
The mechanic at my dealer just told me that:
a) the pipes should NOT be rusting like that and they look like $#!t
b) BMW would not cover it under warranty since it is "ENVIRONMENTAL"
c) I need to call an 800 number to get a warranty rep to look at it.
So, I was wondering - how many of you have or have seen rusting 'stainless
steel" pipes on their f650? I do understand that stainless CAN rust. But I
thought that they'd last a little longer than 7 months (I've been living with it
for about a month or so).
The header pipes on my made-in-1996, 1997 model have never rusted and I live near the Pacific Ocean and ride in fog and salt air every day. Richard #230
Just wrap the pipes with heat protective exhaust wrap. David H. Park
What about that little Cylinder in the Airbox – What’s that ?
It's the vacuum actuated valve for the Catalytic Converter Air Injection system. For more detail refer the Canisterectomy FAQ.
Typical Question
A while back when I installed my Laser muffler on my '97 F650, I removed the secondary air line hose that comes out of the airbox and connects to the exhaust header. I plugged the hole in the airbox with a piece of rubber hose and a bolt. Today I removed the air filter and took a peek inside the airbox to see where the hole leads, and there is a round metal cylinder with another small hose that routs through, and out of the airbox and into the RHS of the carbs. The other side of the cylinder comes out of the airbox to where I plugged it up (if you've seen it, you know what I'm talking about).
Here is my question: Can I remove that entire cylinder and plug up the hose going to the carb, or does that cylinder serve any other purpose? I could just leave it well enough alone, but the part of the cylinder that comes out of the airbox (the part I already plugged up) brushes up against the exhaust pipe, and I'm concerned that eventually it will wear a hole in the exhaust.”
Answer:
The item (cylinder) in the airbox is a vacuum actuated valve. It's opened by the carb vacuum when the bike is running. When it's open, it allows the Venturi at the very front of the header pipe to suck fresh air into one exhaust to feed the Catalytic converter.
If you are never going to use the OEM cat muffler again, you can remove the valve assembly from inside the airbox, but since this opening is on the clean side of the air filter, you MUST seal off any openings in the airbox, or you will suck dirt and water directly into the engine intake. You could possibly leave the valve assembly inside the airbox and just remove the external fitting if that will give you clearance.
I don't think you need to fully seal the vacuum side of the valve if you leave it in place, but a plug or duct tape would be nice to keep dirt from inside the valve. Just as a reminder, make sure the carb vacuum port is properly sealed. Also many people seal the metal air injection line by inserting the proper size ball bearing under the nut or you can just cut it off bout two inches long and thread the inside of the pipe for an 8mm bolt.
Plugging or removing the vacuum actuated valve, or plugging the metal air injection line assumes that you have removed the OEM muffler that has the Catalytic converter. Otherwise, if you remove the air injection system you will most likely clog the catalyst with carbon, eventually killing it. If you have installed an aftermarket Staintune/Remus/Arrow you have no cat, so go ahead. Some early Euro models with the Cat have no air injector. It's possible that the Cat can survive with no air injector with the lean OEM jets, but if you have re-jetted richer for your new exhaust system and decide to reinstall the OEM Cat exhaust, you should reinstall the OEM jets and the air injector system.
What is that little Bolt on the the muffler ?
Do you mean the plug in the pipe before the CAT? It is a test port to measure exhaust gas (CO) before CAT. For use with a Exhaust Gas Analyzer. DWM #365
The exhaust gas sampling port is pictured on page 00.10 of the factory manual, figure 00.030. Bryan #179
The Exhaust System section of page 18.1 of the Manual, doesn't show the bolt.
What is that Exhaust Extension Thingy I got with my Bike?
It's provided by some Side Pannier Manufacturers, so the exhaust doesn't heat/melt or dirty your Soft Side cases.
What about cleaning
the Exhaust?
Haakon # 626, Norway
Some time ago some CG members asked how to clean the exhaust system. I then suggested to use a chemical used to clean up stainless steel after welding or heat-treatment. I just did a small test to show how well it works.
I have just finished "cleaning" part of the left hand exhaust.
As I had to do it in the shower, instead of outdoors (due to low temperatures outside), I just covered part of the "can" and pipe. The more you use of the chemical, the more poisonous gas is produced.
I washed the exhaust with hot water and soft a brush.
-picture: "Before1, 2 and 3".
Wait until it is dry and apply the liquid/ gel. -picture:
"Just applied".
After 1 hour.- picture "1 Hour" - here you
can see some lightening in the yellow/ blue/ brown.
After 2.5 hour I washed the parts with hot water and soft brush and let it dry.
End result, -picture "After1, 2, 3 and 4".
Here is a word document with what is IN that stuff. Pretty dangerous looking mix.
Why
is my Exhaust Glowing?
Q. Went down to fill up the coolant on my bike. It was dark and cold out.
After I filled it up, I turned the bike on to idle. After two or three minutes I
looked over and noticed that the large metal pipe that comes out of the top of
the engine and heads to the exhaust was bright red at the top!! Is that normal?
I rode around a little to see if it was something that needed wind on it to keep
it from happening. But it was still there. IS something wrong with my bike? The
overheating light does not come on. Just called my dealer. They said that
it is totally normal...that in the dark every f650 header pipe will glow "cherry
red" after a few minutes. Basically what the guy at the dealership said
there should be NO warm up time with the f650 bikes. Get on and go. Seems
strange to me, but when in Rome...
Normally:
I assume you are referring to the header pipe. They often glow red,
particularly in the dark. That's why they change from "chrome" looking stainless
steel to yellow or blue looking stainless steel. Heat does that. Flash 412 (CO)
But sometimes, especially if you have a GS or CS:
Sorry to be the
bearer of bad news, but this is not what you want to happen. The same thing
happened to me, it turns out the sensor (oxygen or fuel, sorry I can't be more
specific than that) needed to be reset. To do that you will need to disconnect
the battery. Just remove one of the terminals and then reconnect it. That
should take care of it. If this does not correct the problem, the sensor could
be bad. What is likely happening is the bike is running too rich and the
excess fuel is being burnt inside the exhaust, not good.
When I went through this, I called 3 different dealers and got three different
answers, basically it boils down to this:
1: "I dunno, never seen that happen before"
2: "They all do that, I have seen them glow white-hot before"
3: "Most likely the oxygen sensor, try resetting. . ."
The reason I made the 3rd call was because my bike had not glowed prior to my
letting the battery run down. Once I made the reset, it has not glowed again.
I don't believe it is "normal" and I am glad I found a dealer/tech who was
able to help me solve the problem. Whether you think it is normal or not, what
can doing the reset hurt? It takes very little time and costs nothing.
I do remember the dealer giving me some instructions after reconnecting the
battery, they were very simple, but I don't remember exactly what was
included. I think it basically was turn the key on, wait for the abs/oil
lights to go out then start the bike without using the throttle!
Again, this worked for me and stopped the glow!
Tim.
Since disconnecting the battery will also reset the FI, you need to follow the "init" procedure described in the FAQ to have a nice functional bike after. NLS
That is apparently the primary reason BMW wants you to ride off immediately upon starting the bike up in the morning. The FI fast idle/starting mixture on their engines (including the twins) apparently is a regular blow-torch and they want you to get moving to cool it off. Richard #230
What about Jet-Hot Ceramic Coatings?
A lot of the K1200RS and R1100S riders have their headers, etc. coated and most have reported very positive results. I've seen their promotional video and considered it before selling my K12. I personally don't plan to coat my Dakar. Kind of like it as it. YMMV. RogerN#827
Supposedly "JetHot Coating" has all the benefits as well as EXTENDING the life of header pipes, and has the added benefit of trick colors. One fellow who JHCed his Triumph header pipes noted a 10°-15° drop in external temp. The JHC, OTOH, puts a thin ceramic coating on the INSIDE as well as the outside, so it insulates the PIPE as well as the surrounding components. The excess heat goes out the exhaust.
I had the horribly rusty exhaust flange thingies on my Guzzi jet-hot coated; 30,000 miles, four years and millions of toasted bugs later the coating is still holding up just fine. If I had lots of money I'd have them coat the aftermarket mufflers I purchased for the bike which came pre-rusted from the factory in Italy. Shank
Well worth the money had the head pies done 3 years go. No more blue just silver back to the Staintune cross over pipe. Peter Jensen #233
What about Spark Arrestors for Forest Roads?
by Bill & DHP#711
Short answer. We don't know for sure. (Can anyone help?)
I have tried the coat-hanger-into-the-muffler test and the hanger butts up against a barrier at the forward end of the primary muffler (left) So it should pass a trail test performed by a Forest Service official. But does the bike have an USDA Forest Service Approved spark arrestor?
The F650GS Dakar is a fully qualified road bike and as such doesn't have a spark arrestor (as far as I know). It's exhaust includes a catalytic converter and therefore is in a different qualification from a "normal" off-road or dirt bike. Any Forest Service person who asks for this test, green or red sticker should just be shown your license plate which is for a normal motorcycle (i.e. no restrictions). DHP #711
How bad is leaded fuel for the cat?
Q. I am going on a trip and in some of the countries I'll visit it could be possible that I will have to use leaded fuel in remote areas. I know that leaded fuel is bad for the cat and that it will block it, but would it be ok to fill up the bike a couple of times without destroying the cat? How much leaded gas will it take to destroy the cat? Since I hopefully won't have this problem I don't want to remove the cat. However if it is very bad for the cat to be exposed to leaded fuel and I notice that there is a problem finding unleaded gas in remote areas, I'll just let a local welder in that specific country remove the cat. Regards, Spakur #1117, Icelander in Malmö, Sweden, 1995 Classic Red F650 with 65.000+ KM
All I know for sure is that leaded fuel will (eventually) kill the cat. And, if I'm not mistaken, the deceased feline will clog the pipe to the extent that the engine will die too, and you'll turn around expecting to see Eddie Murphy stuffing bananas up the tailpipe. Now, I have no idea how long it actually takes, but I wouldn't risk filling up with leaded gas a couple of times only to have a blocking cat kill the engine in the middle of nowhere. Perhaps you could find a cheap, used exhaust system somewhere and remove the cat from that one? If you don't want to screw with your own, that is? Emil '94 F650 -- Malmö, Sweden
From what I have
heard a few tanks of leaded fuel may reduce the efficiency of dat cat, but
should not put it out of business. I think it will take a lot of leaded fuel
to actually clog it. My neighbor managed to clog the cat on his car and bring
the thing to a stop on a freeway hill, but he was using leaded fuel for
several years before that happened.
Richard #230: 1997 Funduro.
I asked this question (indirectly) to a senior guy at BMW America a couple of years back (before heading to South America), and the reply was 1: the cat gets irreparably damaged very quickly but 2: apart from the exhaust running hotter (and dirtier than normal their would be no lasting damage to the rest of the bike. Lance, #1303, '01 F650GS, '96 G650ST.
Its also my understanding that leaded fuel will very quickly cause the converter not to function. The lead will coat the surfaces of the catalyst preventing the conversion from taking place. I also agree that there should be no other damage to the bike. If you need this converter to work so your bike is legal in your home country my guess is buy a non cat pipe for these exotic trips so you don't end up paying $$$ to keep your bike legal at home. echo