I am going to use this thread to document a step by step procedure for the installation of this Athena 290 Big Bore into my Yamaha WR250R. Lots of folks have asked me for a detailed pictorial and explanation. So, here you go! I'll take you through my very own "discovery process" as I disassemble my stock engine, and replace it with this bad boy. I'll also include my tuning procedures all the way through completion.

You will notice I perform all of these procedures in my little 'ol cramped & messy garage floor. Nothing fancy about it. But someday, I hope to improve on that.

Fill your popcorn and get a big drink....then kick back and enjoy the show. I will share some of my own little tricks along the way, which might make your wrenching efforts a little easier too. I've never dug so deep into this bike before, so we are bound to learn some interesting things together.

Here we go....let's find out if this box of goodies is worth the expense.

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