Don't sell!!! You can get into a capable, travel worthy dual sport fairly inexpensively. Pick up a used dual sport for your off pavement camping and exploring. Just don't get rid of the CB550, what you have there is a nearly perfect Café project.
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If we're honest with ourselves, our ratio between paved miles and dirt miles tips way to the pavement side. Bikes are a segment where specialization is king. No bike can do everything...well. Some flirt with competency in multiple areas but in the end, they are compromises. Bikes really are a tool...pick the best tool for the job. That CB is the right tool for looking cool around town.
I just got back from a couple of month's down in the southwest knocking around. I took my new to me 250 Yamaha WRX 250 in place of the TW200 that has accompanied us for the last eight years. It was much more comfortable with real suspension and enough power to easily keep up with traffic. Much as I loved the old TW I think that this is probably a better bike for what we do. It weighs pretty much the same has 2.5 times the power,a six speed transmission and fuel injection. It gives two people room to stretch out a bit more and the riding position is more comfortable for me. The x is the super moto version and this one has dual sport tires, a 3.8 gallon tank and the same rack system that I used on the TW200. It will knock down 65 miles per gallon if you don't rev it to the 10,000 rpm redline. I think that as a bumper hauled bike it is worth considering over the more common choices.
Before dual sports and adventure bikes, there were companies turning cb's in to scramblers.
I've had dozens of bikes, and they're never the right one.
Back in the early 80s, before there was anything called an adventure bike, we just rode what we had. My 82 Yamaha 650 Maxim took me all over the country, down dirt roads, gravel, trails, camping in the woods, BLM land, etc. Nobody told me I needed knobbies for this, so I just made do with the ****ty street tires we had back then. Looking back, it had no suspension, not much clearance, and not much range. Again, not knowing any better, it did just fine. Amazing how freeing complete ignorance was.
Now that I know better, no bike is right. I currently have an 1150 ADV and a KTM 500 EXC, and neither one seems perfect at any given time. I keep trying to justify a 690. I think I was happier, and richer, when I was dumb.