400banshee Posted February 20, 2011 Author Report Posted February 20, 2011 Never running a 485, my opinion might be void but 145 main and 44 pilot jets on that large of a motor sounds incredibly lean. Most 421cc cubs are running 160+ mains and 50+ pilots. What is your elevation? It could be possible that detonation/heat cracked your insulation? Anyway, carry on... 891 feet a.s.l Quote
pabansheematt Posted February 20, 2011 Report Posted February 20, 2011 I ran my 492 with 35mm carbs for years with 145 mains and a 40 pilot. When I went to 38mm carbs i run 162 main and 45 pilot. Every motors different..I also jetted a couple 421 cubs. There mains were in the 165 range, 45 pilot. Quote
pabansheematt Posted February 20, 2011 Report Posted February 20, 2011 Never running a 485, my opinion might be void but 145 main and 44 pilot jets on that large of a motor sounds incredibly lean. Most 421cc cubs are running 160+ mains and 50+ pilots. What is your elevation? It could be possible that detonation/heat cracked your insulation? Anyway, carry on... Usually when the main is to lean the piston melts. I've seen it happen more then once. This was not the case. Quote
gotta_goatsfast Posted February 20, 2011 Report Posted February 20, 2011 Interesting. I'll never be able to own a powervalve banshee or anything much larger than my little 421 serval so I'll go back into my corner of limited knowledge. lol. Maybe it was just a 1 in a billion messed up plug that somehow made it past quality control? Quote
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