I have joined just to contribute to this thread have had 3 XL600R's over a span of 23 years. They are great bikes . My current one is a 1984 model with a dyno jet kit and a super trap muffller it has 16000 miles on it and runs great. In fact I just purchased a 2008 KLR and the old Xl will out torque it out accelarate it and is just a lot more fun to ride and fun is what it's all about.
Does anyone have a dyno graph on the old Xl,s I would like to compare it to a KLR?