My research has shown me that the best way to build a YZ144 is to change the stroke and bore. There is currently a kit on ebay. I'm just wondering if anybody has some feedback that has done it. The new KTM 150SX is a very impressive machine, especially with the new linkage suspension. The Athena big bore kit only produces only a modest power increase that is insufficient against the KTM. I'm curious if it can be done.