Fine tuning the carbs- any good ideas or hints?

[rug_burn]

After a carb cleaning and (mostly) rebuild, I synched my carbs, and it ran pretty good. 
   I noticed however, the carb mixture was off:  some cylinders were running lean and therefore hot, others not.  Mainly the right carbs were the lean ones, the left side were running more normal. 
   So I started adjusting the pilot needle, opening to make the lean cylinders richer, and get them all in synch, mixture-wise.  After a typical half hour ride, I would check exhaust pipe temps with an IR thermometer, not real reliable for many reasons, but my options seem limited.
   Then I've pulled the plugs and checked their color-  the rights were all real light, bordering on yellow, the lefts were mostly med-light brown. 
   So I been playing around with this, dialing in individual cylinders using spark plug color as my main guide and I've got it running a lot better, getting kind of close to the factory setting, but I want to ask all of you:   

 What is the best way to set the mixture correctly without any high tech analytical equipment?   

I've read the manual's suggestion, which seem tedious in the extreme, and still just arrives at the setting of just this one screw-  the pilot needle.

Anybody got any comments or good ways of doing the adjustments?

And what exactly does that pilot jet do?     My theory is that it allows vacuum up into the area above the diaphragm, which pulls up the needle, which then allows the gas to go by adding to the fuel/air mixture.  More pilot screw open=more vacuum=more rich mixture.     Is this right or am I completely full of shite on that?   I admit, I haven't really gotten down to research it.

[WintrSol]

The pilot circuit draws fuel through a calibrated hole (jet) and mixes it with air from another calibrated hole (air jet) in a bubble chamber. The pilot screw controls how much of this bypasses the throttle plate, via a small port downstream of that plate. When at or near idle, the throttle plate is almost closed, but the air flow is too low to draw fuel through the main circuit, so the pilot mixture is added to keep the engine running. The pilot circuit also feeds small ports upstream of the throttle plate, to help with the transition from idle to above idle; these ports are not controlled by the screw.

The only way to get the mixture right is with an accurate tachometer, and follow the procedure in the manual.  With 6 cylinders, this can be tedious. A good ear for 'music', and aiming the exhaust at a wall, can help, as you may hear the cylinder you are adjusting begin to move off optimum by changing the sound of the exhaust; again, with 3 cylinders feeding each pipe, this takes patience.

[rug_burn]

Thanks for the info about the pilot jet-   and using the wall for a sound reflector sounds like a  good idea

It sounds like one of those things that's an art as much as a science

[98valk]

plug reading basically cannot be done with unleaded fuel. insulator will stay basically white.

I dyno'd mine two yrs ago on a FactoryPro dyno with exhaust gas analyzer, was pig rich at 10:1 at WOT and perfect air/fuel everywhere else and the insulators were basically white.

with today's unleaded gas only an O2 sensor or exhaust gas analyzer will let u know for sure if its lean.
As Marc the owner of FactoryPro once told me, it is what the engine wants and not always the numbers.
Meaning use his CV carb tunning instructions and see how it runs per. Just use third gear on the hwy.

[rug_burn]

ON mine, there were also other indications it was lean- for example:
  1.  When I'd pull in from a 20 or 30 minute ride, fairly hard in the final part, it would smell hot, especially above the right exhaust when parked, right after pulling in.  IIRC, it smelled quite a bit different before my carb adventures.   I wish I'd paid better attention before this all happened. 
2.  When I'd be going up some incline, and roll on the power, it'd kind of sag for a little bit, like it's lean, and I'd have to roll on more to get the desired response.   I remember the power was always right there, with only a little crack of the throttle, before.  And the engine makes more noise, and kind of labors.  The throttle response was better before, in other words.   
   So right now, I'm going to run it for a tankful or two, and check these signs, and then maybe adjust it a little more, as needed, using my flawed, somewhat lacking technique.   
  If need be, I'll have to go to the book procedure, but I'm not sure I can even do it with the engine running-  I mean with that tool, and holding it up on the screw while kneeling over?  I ain't that young any more.   
   I gotta say, it is running pretty good right now, seems to me, maybe a little lean all the way around, but fairly close to being right.   I'd like to put it next to somebody else's and compare how it sounds,  I actually forget how it was before.

[98valk]

if u are stock intake and exhaust.
a sag can be too rich until the engine rpm goes up on that rich mixture and the engine sucks in enough air to burn it.

open all mixture screws from lightly seated to 2 1/2 turns open.  front two carbs add one extra washer along with the existing one on needles. This is per FactoryPro and it works, due to the bowl level can be a little lower than the other four carbs, since they get their fuel from the middle carbs, whereas those four get it directly from the tank fuel line.

re-check for any possible vacuum leaks, hoses, intake manifolds and their caps and/or hose connections, carb boots inlet and outlet and needle slide diaphragms installed correctly and no tears.
re-sync carbs. go for a ride......

IR thermometer on pipes works two ways, too lean temp is higher, too rich temp is higher. so other meters are needed to dial an engine in. most racers abandoned temp reading for the temp reasons mentioned when the more advanced O2 sensors became avail.

[h13man]

Level the bike if you can to get a better synche. Remember this is a gravity flow system. This was suggested earlier this season and sounds right to me but haven't done it yet.

[rug_burn]

Yeah, an O2 sensor would be good, wouldn't it?    I remember long ago hearing that what they do is switch indications at the ideal (stochiometric) mixture.  So it would be, for example, a high indication at rich, switching to low at lean.  Or the reverse.   We need to research this.   Actually, it might be possible to make one using a microcontroller...   That's one of my other hobbies, and I know I'm not alone in that.

[rug_burn]

Yeah, that's right;  it tells about it here:
http://www.autotap.com/techlibrary/understanding_oxygen_sensors.asp

so to read one you'd need to rig up a microcontroller, and the simplest way would be to have it switch a 2 color LED from green to red, for example, when it crosses the ideal mixture.