by xrongor » Mon Jul 21, 2008 4:57 pm
as to cleaning out the port in the cylinder, pull the cylinder. scrape it with wood or plastic so you dont scratch the metal. an old toothbrush can be filed to a chisel and works well. replace the cylinder base and head gaskets when you get done (less than 10 bucks from a yamaha dealer).
as for the yt60 swap, i did a full compare for myself when i upgraded. the only different parts you need are the piston, rings, cylinder, and head gasket. the rest are exact matches with the QT50. (base gasket, bearing, rod, pin, clips, etc..) and i think some people are still using the QT head gasket although imho its better to get the YT one. same price for both...
as for oil, 1 cc = 1 mL (mililiter) and most measuring cups have mL markings right on them. no need to convert to ounces. 300 mL will do it.
as for jets, youll just have to do plug chops. somewhere between 60 and 75 will likely be the correct size (lower altitudes require higher numbered jets). from what ive seen you should expect to go up 5 in size if you switch to a 60 from a perfectly jetted 50. but again, chops are the only way to be sure.
randy
"In this world there's two kinds of people... Those with loaded guns, and those who dig." -- Blondie to Tuco