It is a well known fact among us dirt bike riders that you stay away from Optimax because it leaves deposits and fouls plugs. For that reason I use Techron Gold in my KTM and have no problems. In fact when I bought the bike the dealer expressly told me not to use Optimax in it.
BA'1.5' Pursuit 290
Lightning Strike / Reflective Orange Stripes
'General' Dog - AP's German Shepherd and Best Mate - 02Dec1998-15Dec2003.
'Pepper' Dog - General's and My Little German Shepherd Sweetie - 1996?-02Apr2006.
'Sako' Dog - My Beautiful and Pretty German Shepherd - 2001?-23Aug2006.