jetting/oil mix/spooge

[grease]

i got a 99 rm125. I am running a 170 main jet. I run 40:1 castor 927. my plug seems to be black every time i take it out and fouls often. It smokes a lot. Needing some help on which oil mix to run at which ratio with that jet. I've heard good about CCI and MX2T. What do you suggest. Also what is spooge can you help me out and tell me what i need to do to see if i have any.
Apreciate all help/
thanks

 

[02'Cr Rider]

Do you use castor for the smell?Cause its dirty oil.Use an oil as you mentioned,like mx2t ,yamalube,or golden spectro if you like the smell of some what castor.Try running these jetting specs @32:1 mix.

168 main
55 pilot
stock needle @ 2nd from top
air screw @ 2 turns out

Try it out and see if it work,tune from their.