Plug color?

Bike is running great but the jug has a boost port and on the plug one side is black the other half is a deep brown.Wondering could this be from boost port?Running a 68 main needle in 2nd from top.Gonna try needle clip in first position and read the plug.What do you true tuners think?Maybe I can get a tad more out of this engine.(jetting)

Make sure you start with a fresh plug to get an good reading. Dark brown is a tad rich.

Thats the reading I got with 3 new plugs on plug chops.One side deep brown the other side black.

No that is lean

This is not a bad thing because you are on the border. This can be caused by the fuel mixture or type of oil your using. What mixture are you running and what type of 2moke oil? If your air filter is really dirty it can cause inconsistant reading also.

Running yamalube synthetic 40:1 airfilter is in good shape.Thanks for the reply

Hope this helps.. Dry black with somewhat fluffy browning.

Common causes for a rich air/fuel mixture are:

dirty air filter.
air mixture screw or carburetor needs adjusting.
choke is sticking.
carburetor float height is out of adjustment or float is sticking open.

I made a 3 stage reed with 2 sponsors reed parts.I ran the bike pretty hard and low and behold did a plug chop plug nice and brown all the way around.The reed that I used was a tad stiffer than the original that came with the kit.Mid and top pulls harder and longer.I think the reed that came with the kit flow too little at one point and to much at another due to the 3 stage affect.I must say the orginal kit was ok till the reed failed.Now bike runs great plug is nice brown.On my way out now for more testing on the coustom reed.

I can say now this combo is graet for my combo.With the b/w kit on the straights it would tach out.Now on the same lot where it would tach out it pulls harder and is still reving out where befor it was tached out.(more power and speed)Still got a few hundred rpms left.I made a great 3 stage reed.Thanks to ada and pbu and some knowledge how these engines perform.Got more ideas on reeds.Once you learn how a reed effects an engine you can coustomize your own for your ridding style.Pretty much where you want your pipe to hit.Earlier than the .3 and later than the.5's with a coustom peedle to do what I stated.As (Sam) boosted306 would say stay tuned guys.I wil be ordering material for fg and cf to do some testing and get us all the bang for the buck.