So I'm nearing having put 1000 miles on my new to me KLR, mileage is nearing 4000 on the bike. The one thing I've noticed is a weird resonant increase in vibration at 4000RPM. The bike seems to have normal linear type thumper vibration from 0 - 3900 RPM, but at 4000 there is an amplified feeling. I have read over quite a bit of threads in multiple forums about this, but not 100% sure of the answer. I have not yet installed my Doohick+torsion spring, but I did read in one thread that EagleMike himself noted "flawed balancer weights" in some models. What's the overall opinion here? I can put up with the vibe if it's a healthy vibe, but it seems odd to me that the vibe is almost increased 1.5X at the 4000RPM level. Its definitely a rotational vibration specific to the engine. But why this "surge" at 4000?