goirish,

          Why did valve stick to begin with?   

Even weak springs should not keep valves from working although they might not seal they should still move freely.

Are you using castor as a lubricant?  2 years running is time to gum/glaze an engine, you might consider using synthetic lubricants. Just keep it rich.

Good Luck!
                                                                    Oscar


                                           It's what you learn after you know it all that really counts. (Junior Johnson)


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