Sep 04, 2010· Valve lapping DIY without special tools. ScootDawg's Scooter Forum The Dawg Pound. Rules, New Member Introductions, and Forum Information ... 2 Stroke 50cc + Engine and Transmission. 4 Stroke 49cc + Engine and Transmission. ... Go to to the parts store and purchase a tube of valve grinding compound. You will find it in the adhesives section.