First of all you guys have been great! I learned alot from this site. I recently did the Dave's Mods and it was nothing that threw me off the back of the bike or anything...but have noticed the bike runs really smooth now...NO MORE BACKFIRING. I do alot of off road riding and my buddies have noticed that when I get into the gas white smoke comes out the exhaust. This has been going on for some time...has gotten a little worst. I've been told the likely cause is a blown ring(what ever that means). Here is what I'm thinking I might do....give me your imput. The BRP(learned that from this site) 2003 XR650L 3,400 miles. First off- road bike for a 38 year old rider. Has been great...gets rid of stress. 1. Just replace rings. (is this a do-it-yourself job?) 2. Send the head to Thumper Racing for the 675 cc upgrade? I ride with a guy who has a SXC 625....Wow..what throttle response. A last note.. I go everywhere he goes on that KTM and I don't care if my bike goes 100 mph or not I want low end grunt...HOW CAN I GET IT OUT OF THE BRP?