Saw your question in the jibber box. Take the cover off - Spark Plug out See the small motor sprocket? Find the socket that fits that big nut, spool your chain up from the underside turning that big nut clockwise. WATCH YOUR FINGERS! Once you get it up over the top you should be able to pull the chain thru. Try to meet both ends on the backside of your wheel sprocket. Link the chain there. You got a chain breaker? By removing your spark plug you take the compression resistance out of the equation. Always turn the big nut spool chain up from bottom clockwise to prevent loosening the nut. I don't use a tensioner but the procedure is the same. be glad to answer other questions you may have. check out my albums, good luck!