Dan, I wouldn't try and lap that cylinder if its not necessary. The steel wool 0000 is what Cox recommended in their instructions. It stated to use a little light weight oil in addition. The Davis diesel brush is available on Ebay for about $6.95. Its not a needed item just a valuable maintenance tool just like the piston reset tool. Keep in mind that Xenalook is providing high compression plugs now. If the engine is gummed up like you've stated, hows the crankshaft? I've needed to seperate the drive plate off the crank and polish the crank up. I've had the castor gum act as a brake and wouldn't let the engine come up to rpm's . This can also lead to overheating. That stuff is a great preservative but can really dampen engine performance. After I have the crank out I chuck it in my drill press and use 2000 grit and oil followed by metal polish. Its probably more than adequate just to remove the castor varnish for good performance but I take it another step. Ken