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I ordered my aftermarket exhaust just in time! On a ride yesterday my "quick fix" blew off the holes and cracks in my 23 year old mufflers. I should get the parts in a few days.

I really didn't want fancy or a racing look. I ordered simple slash-cut side-draft mufflers with removeable/repackable fiberglass packed reducers.

I'm hoping to avoid a nightmare with the possibility of having to rejet. I'm assuming that if the bike runs a little lean or rich I'll be able to adjust the amount of fiberglass material in the mufflers.

So, what to look for in the plugs and pipes? Yellow/tan good in the plugs and sooty or white ash bad? What about blueing or yellowing of the headers? I don't want it too lean and damage my engine!

I'm going to get a baseline check before the change yet the holes in the mufflers concern me about the current accuracy. Then periodic checks.

What a pain in the rear but the stock exhaust are no longer available and too expensive in any case. The two mufflers cost me less than $50; the pipe and labor should be less than $100.

OK, so this is what I understand from your post - You will be getting the pipes custom made for your ride??

If this is the case, I would install something like this http://www.knfilters.com/airfuelmonitors.htm

You need to have your pipe maker weld in a bung for the o2 sensor where the pipes come together - For your bike, it's best to have this done at a collector box or an H-tube - somewhere the exhaust all comes together.

Note that an 02 sensor needs to be warmed up before it will give accurate readings, but once you have everything back together and the bike is running well, this will provide an Excellent way for you to get the proper tuning set - and to maintain it!

Even is you don't want the extra gauge on your dash, you can just plug it in occasionally when you think you might need a little tuning and go from there. Also keep in mind that this (K&N) gauge may not be weathertight. I'm sure there are bike-specific gauges made, but not sure who sells em. At any rate, all 02 sensors are the same, so the voltage they put out should be measurable with any gauge. If you want to go the cheaper route, put the o2 sensor in, and just use a Multimeter to test the voltage off the sensor - The bung should only cost a few bucks for the guy to weld in, and a normal one-wire o2 sensor is only about $20 at a local auto parts store.

It should be noted that o2 sensors put out less than 1 volt, so you need a sensitive digital meter to read it properly.

Bluing of the pipe headers will accur regardless of the mixture you are running, running rich may help reduce the CHT slightly, but the bike will run rough before making any appreciable difference.

The only way to prevent getting blued headers that I know of is to have double skinned pipes.

I'd set the mixture for the light grey/tan colour, and if the headers go blue, console yourself with the thought that loads of people pay good money to have blued pipes.... yours came for free!

S.

The idea of an O2 sensor really is fantastic!

The K&N kit is like $250. Nice but too pricey at this time. I wonder if there is another manufacturer but they all want money, hmm? But... an O2 sensor in the crossover or each pipe or a bung in each pipe would work too. Multimeter should be no prob.

What ranges of voltages? The higher the voltage the leaner? "Monitors have red, yellow and green lights that require 100 millivolts per light for a total of 1.0 volt" according to K&N. This still raises questions for me. This really is a great idea and the dyi'er geek that I am will probably go this route.

I'm not replacing the full 4-2 system of exhaust- just the Mufflers back to the exhaust pipe with some extending to make it look right. You can see in the picture below where it tapers down below the foot-peg. This is where the cancer is. The new mufflers are half the length of the old. I think I could put a fitting on the inner side of the replacement pipe and insert a sensor when I need a reading. Then go to the other and compare.

Another flash of inspiration! Run the wire through some tubing with the sensor on the end and insert in the end of the exhaust a ways for periodic checking. Would this work too?

I just found tis on the web:

How does an O2 sensor work?
"An Oxygen sensor is a chemical generator. It is constantly making a comparison between the Oxygen inside the exhaust manifold and air outside the engine. If this comparison shows little or no Oxygen in the exhaust manifold, a voltage is generated. The output of the sensor is usually between 0 and 1.1 volts. All spark combustion engines need the proper air fuel ratio to operate correctly. For gasoline this is 14.7 parts of air to one part of fuel. When the engine has more fuel than needed, all available Oxygen is consumed in the cylinder and gasses leaving through the exhaust contain almost no Oxygen. This sends out a voltage greater than 0.45 volts. If the engine is running lean, all fuel is burned, and the extra Oxygen leaves the cylinder and flows into the exhaust. In this case, the sensor voltage goes lower than 0.45 volts. Usually the output range seen seen is 0.2 to 0.7 volts. The sensor does not begin to generate it's full output until it reaches about 600 degrees F. Prior to this time the sensor is not conductive. It is as if the circuit between the sensor and computer is not complete. The mid point is about 0.45 volts. This is neither rich nor lean. A fully warm O2 sensor *will not spend any time at 0.45 volts*. In many cars, the computer sends out a bias voltage of 0.45 through the O2 sensor wire. If the sensor is not warm, or if the circuit is not complete, the computer picks up a steady 0.45 volts. Since the computer knows this is an "illegal" value, it judges the sensor to not be ready. It remains in open loop operation, and uses all sensors except the O2 to determine fuel delivery. Any time an engine is operated in open loop, it runs somewhat rich and makes more exhaust emissions. This translates into lost power, poor fuel economy and air pollution. The O2 sensor is constantly in a state of transition between high and low voltage. Manfucturers call this crossing of the 0.45 volt mark O2 cross counts. The higher the number of O2 cross counts, the better the sensor and other parts of the computer control system are working. It is important to remember that the O2 sensor is comparing the amount of Oxygen inside and outside the engine. If the outside of the sensor should become blocked, or coated with oil, sound insulation, undercoating or antifreeze, (among other things), this comparison is not possible."

If you are just changing mufflers, your A/F ratio probably wont be affected very much.

I have found that it is possible to fine tune with muffler packing.

I put a 2 into 1 exhaust system with all steel baffles on my Hawk. I found it to be too loud and the engine was running a bit lean. I fastened some long strand fibregalss muffler packing around the baffle, and after a little trial and error, I got it right. The raspiness is gone and it seems to be running closer to the ideal air/fuel ratio.

I like the O2 sensor idea. Not sure I want to permanently mount one in my exhaust though.

If you are handy with a soldering iron, you can make an airfuel ratio gauge for a few dollars. I am planning to make one for my Saab turbo. I can post a link to the instructions later if anyone is interested. They are on my home computer.

Yes please... that would be ideal. I'd like to have a air fuel sensor handy, possibly one that can be fitted on while tuning and syncing carbs... and then removed

I've looked at the web page. Interesting.

http://www.scirocco.org/tech/misc/afgauge/af.html

I think If you were Handy and able to mount the O2 sensor out of the way you could get by with leaving it in. They are designed to be left in cars and routinely get 50k plus before wearing out. With a little trickery and cusomization with the guage you could monitor your mixture all the time if you wanted.

My only concern is that they need to be 600 F before they work. I'm worried that by the time the gases get to where I could put it on my bike they will have cooled down too much. On cars they are right after the header if they aren't self heating. So maybe a three wire (self heating) would be necessary.

BTW- Bosch universal single wire O2 sensor at Autozone is $16.99

yeah its the heating thing that I was worried about. having a self-heated probe kinda thingy that you could stick into the exhaust while tuning would be handy. I'd rather not drill any holes right next to the flanges on the headpipes.

Picked the bike up this afternoon between reading posts on this forum, Hee, Hee.

Looks great! Sounds fantastic! Just checked the plugs after it cooled down enough to get after it. They looked perfect really. I had to regap them since the fool who I bought the bike from obviously didn't gap them at all. They were quite off. Then I raised the Idle since it had dropped after the gapping.

Just waiting for the clamps to arrive and it will be ready for a picture to post.

I'm gonna give her a run in a few minutes. Any advice as to how often I should check the plugs? I normally don't ride it too hard (as in redlining) but I'm not shy either. I've been led to believe that "granny" driving will foul the plugs eventually.