multi-colored exhaust - carbs?

I recently made a switch from the colder NGK B8 plug to the hotter B7 after noticing that the B8's got carbon fouled when I started using ethanol free gas. After running a couple of tankfuls on the new plugs I pulled them to see how things looked.

#2 and 4 looked good - insultor had a tan color and the electrodes were clean. #1 and 3 had gleaming white insulators. In addition the exhaust headers on 1 and 3 had blued a bit while 2 and 4 only have a very slight yellowish tinge - all coloring happened after I put in the 7's (I bought the bike with B8's in it and assume the cooler 7's had not been run)

Timing and compression are good, everything is gapped to spec including the valves. I have not synched the carbs since I bought it.

Thoughts? Should I be concerned about the heat levels I'm running on 1 and 3?

7's are a hotter plug.
Tan is a good colour.
White = lean. Enrich mixture.

I find 7's to work best in my bike. # 8 are good for the highway.

Would assure correct floatbowl fuel levels. Carbs #1&3 might be too low.

Imo, it's best to tune for KHI recommended plugs, usually NGKB8ES for large fours, sometimes B7 for 650's. Follow the FSM.

Good Luck!

for this time of year the 7's that you have put in could cause hot spots and cause pre ignition if your timing is advance a bit to much to be onthe safe side stick with the 8's or even 9's if you are running the bike hard.

i don't run the bike hard, I'm not exactly grandma but my days of trying to prove anything are behind me for the most part. i think.

As far as i know FSM says use 7's for around town and 8's for long rides or if you are carrying a lot of weight. A lot of other 650 guys run 7's and have good results.

8's started fouling a lot when I changed to non-oxy fuel and 2 and 4 look exactly like they should - I think floats is the way to go next. I'll keep yall posted.

You are right on the money with the plugs.
The 7's can last for a season, the 8's carbon foul in a few weeks.