So I replaced my spark plugs yesterday and cylinder no.3 and no.4 had a little oily thick black sludge above and around them. No.2 and no.1 cylinder had normal wear and tear. Is this something to worry about and is there an additive that works really well for you guys bg44K etc.. Thanks

 

Run a compression check on the suspected cylinders, could be a leaking valve stem seal or your rings are starting to go.

Ignore it and ride on!