Plug burn with Expansion Chamber>?

[geebt48cc]

:helmet: The 48cc Skyhawk is running good with new SBP Expansion Chamber. I've done nothing but bolting it on the bike (someone said I should lengthen copper pipe on stock kit 1/2"? Stock is 2.5 length, right off manifold, first piece that's copper. Top end is stronger, Mid's/Low's are about the same as it was with stock muffler? It still isn't wanting to run with choke in the total down position (about mid-way) I did a plug chop and 1/4 of it is a strange almost darker gray, but the rest light tan.

I guess still some air working in somewhere?

Thanks Glen

 

[GearNut]

It could be that you have an intake leak. The grey color is most likely from the pre-mix that you run. Different additives can leave different colors on a plug.
I know that my plug is charcoal grey in color, but the air/ fuel ratio is spot on.