How long do I need to ride to get a proper spark plug reading

So I'm in the last stages of tuning my carbs - the bike is running great and I'm just optimizing at this point. Valve clearances are set, carbs are in sync and I've adjusted the idle mixture using Houghmade's post. Now my spark plugs were showing a bit of richness in the mixture after my exhaust holes got fixed, because I set my idle mixture screws to a richer setting when I still had a holy exhaust

so that's set back to normal, but I'd like to go a little further in fine tuning my carbs. Now I'd like to just read my plugs and adjust my mixture ever so slightly from those readings, but I don't always have the time to go on a few hour rides every time I make an adjustment.

Besides a few minutes warm up, does the engine have to be at full-scale operating temperature to get a good spark plug reading (i.e. to reflect properly how it's running) or can I just run it for a minute, perhaps a quick 5 minute zip around the block and that's enough?

I would take it for a good 50 mile run at all rpms. Then park it and let it cool down before taking the plugs out. I use a IR temp gun to check head temps to see if it's running to hot/lean but that's just me.

The engine has to be at proper operating temp - the OIL has to be hot. This typically take 15 - 20 minutes of spirited riding, depending on ambient temperature.

Keep in mind that the Pilot screws are for adjusting the idle mixture and have less effect as the throttle is opened. By 1/8th throttle they are no longer having an effect and you are completely on the Pilot Jet. By 1/4 throttle you are operating on the Needle. At about 2/3rd throttle the Needle Jet is controlling fueling. The main jet is primarily for full throttle. BUT, every jet overlaps with the others. So all tuning MUST be started at full throttle with the main jets, working down to Pilot screw and float level adjustment. Any attempt to start with the Pilot screw adjustment and finish with the main jet sizing will result in failure.

As I've posted numerous times, the best instructions for carb tuning are found here.

I should also point out that carb tuning is the very LAST tuning to be performed, after all intake and exhaust changes have been made. Even valve adjustment will effect the carb tuning.

As for reading spark plugs, if you are running long reach, or extended spark plugs (you should be), you won't be able to use the ceramic insulator of the center electrode as an indicator. Rather, look at the spark plug body that is exposed to the combustion chamber, where the ground electrode is attached. Also keep in mind that the fuel being used has a great impact on spark plug colouring. Additives in the fuel will change the colour of the spark plugs, with ethanol making the plugs appear to be running lean. The excessive moisture carried by the ethanol and created during combustion, will literally steam clean the plugs. Thus making it much more difficult to establish the mixture visually.

? If your bike won't idle because of the pilot jets are not correct, the mid range is way rich and the bike falls on it's face at 1/2 throttle how can you adjust the mains first? Would it not be the other way around? This it how I have been told to do it and have myself done it for the last 25 years

This procedure is for fine tuning, not for getting the bike running. I found it weird at first as well, but I've spoken to a couple old school mechanics and they have agreed. It has to do with how the jets overlap in use. Obviously the bike has to be running somewhat decently to be able to get the engine to WOT and high RPM.

For most people, this process is too complicated and they will be satisfied with just getting the bike tuned close enough that it runs. Even if it isn't running as well as it could be.

And I should add, this process is similar to how I was trained to tune aircraft carbs, and they are as stupid simple as a carb can be...

Thanks guys - I'll get on that Sounds like a little more work will need to go into it than I had hoped but that's cool I don't mind fiddling around with the bike. Should probably get a set of jets though.. I'll see if I can find a nice source on this continent

I know when I changed my plugs to the iridium its very difficult reading the plugs.Its more work but by removing the pipes and looking in the exhaust ports I can tell if Im running lean or rich.