exhaust gas analyzer for fine tuning

[Stroker Deuce]

The sun came out today and I got the bike out.  The 145 jet is about perfect for my setup and altitude.

[rob f]

Thanks for the info. I am at around 3800 ft and have found  with small engine jetting that is the borderline  altitude for the next jet size. Not sure if I will be messing around with that quite yet but good to know what sizes you have tried.
R

[Stroker Deuce]

I ride at around 5200 ft (1585 meters) and have a K&N air filter with Vance and Hinds long shots.  With this setup I replaced the original 135 main jet that was running lean enough to start coloring the pipe, with a 150 that was too rich.  Just replaced it with a 145 that should be close, but have not yet run it.  I'll keep you posted.

[rob f]

Sounds like specialized equipment but would be the best test for engine performance. Just like us humans. the best way to test for good health is stool samples
A cheaper way but a royal pain  especially on these drifters is a spark plug color check. another would be to thoroughly clean out the end of the exhaust pipes and see how fast they soot up. Trouble with these 2 tests is that a rich idle mix will show up and may give you a false reading of main jets. Been going through this with my Viragos for years. Plus the front cylinder usually runs cooler and has more carbon  showing than the rear. I would do all of fuel adjustments to the rear cylinder as this one runs hotter. Yamaha compensated the Viragos by having one carb per cylinder with different jet sizes. A real finicky system.
Just for curiosity, I see you mentioned that you have been playing with jets. I may start doing this myself but only see 2 different oem sizes that are very close. What sizes have you tried and what is your  riding altitude? Also do you have any air or exhaust mods?
I know that some automotive shops can do it but readings may not applicable to bikes. Muffler shops maybe? Be careful of C.A.R.B ( California Air Regulation Board) especially if you have removed any emission controls. You should be safe in Colorado.
R

[Stroker Deuce]

As I continue to try to find the right jetting for my 800 Drifter, it occurs to me that the right way to do this is analyze the exhaust gasses at different speeds and loads.  I found a good introductory article on this subject http://www.enginebuildermag.com/2008/07/carburetor-tuning-the-airfuel-equation/ , but I'm sure this is just the surface of the subject.

Does any one here have direct knowledge or experience with this subject?  Is this a service offered by shops or builders?