Sorry that it took me so long to get the KDX220 back together, but had to keep son's race bikes in tune.
Did an entire top end rebuild this weekend, including a thorough disassembly and cleaning of my gunked up KIPS. Installed my RB Mods carb and head in the process. Bike started on the second kick and idled better than ever. I took off after a 30 second warm up and the bike ran far smoother than ever before. I'm running an FMF rev pipe and PC2 silencer. At first I thought I'd lost low end, but then I realized that stumble while lugging is not real low end. Instead, I have amazing throttle control over a smooth, strong low end that pulls in linear fashion way past the previous sign off.
Serious bang for the buck. Best customer service, too. Thanks, Ron.