Good morning. Here is the good news. I assert with the greatest respect that PekingDuck and PeterBaron are phenomenal mechanics. I read posts from them and treat those posts like a master mechanics' class. I strongly encourage you to explore their recommendations without deviation.
More good news: you own one of the very best engineered motorcycles that Honda has ever built. Many of the members of this Forum wished they had a CB1100RS because it leans a couple of clicks toward a sport bike relative to other CB1100 Models. Regrettably, we cannot import it into the United States because Honda did not complete the registration process with the United States government to enable it to be licensed. If they had, people on this Forum would be offering to purchase it from you! Hence, have faith and be patient. You have a great motorcycle, and it will in time get to where you want it to be.
I believe you have already received some great coaching. I encourage you to do only one thing at a time and put enough miles on the motorcycle to make a determination about is it right or is it not. Your CB1100 RS should have a smooth, sport ride courtesy of the inline 4 and suspension. It should handle brilliantly courtesy of the weight distribution and braking system. It is already beautiful motorcycle in its current forum.
Let me offer these additions to this thread:
Vibrations: I own a 2017 CB1100EX. it is a more refined, less sport version of your motorcycle. They share many of the same parts and the same engineering. I have absolutely no vibration. However, that was not the case when I purchased the motorcycle. The prior owner had removed the OEM bar weights from the handlebars because he preferred a different aesthetic. I ordered the entire bar-weight assembly from
WeBike Japan and installed them to spec. I also checked the torque for every bolt associated with steering and adjusted accordingly. Most of the vibration disappeared instantly. I would also encourage you to check tire pressure and possibly have the wheels re-balanced.
I did still have two issues left following the bar-end replacement. When I came to a stop or accelerated quickly, I felt minor vibrations. While stopping, I experienced a brake squeal from the front disc brakes. In a move that is incredibly unusual for me, I re-installed a fork brace I had taken off the motorcycle. That non-OEM brace appears to help stabilize the front forks which handle a tremendous amount of weight in those situations. That brace coupled with my natural tendencies to keep everything very clean has eliminated the noise and the vibration I experienced. I am not naturally inclined to move away from OEM designs, but this particularly addition (inexpensive and easy to install) has made a difference on my CB1100EX. I cannot recommend it for your RS, but I can encourage you to consider exploring that option.
Valve-Lid Gasket: It surprises me that you have a leak. It suggests that an inexperienced mechanic worked on your motorcycle. I encourage you or someone you trust to purchase a replacement gasket and install it to spec. I cannot over emphasize the importance of cleaning everything prior to install and using a torque wrench.
Hope my contributions to this Thread help. If my input conflicts with the wise counsel of Lord Popgun, Cormanus, PekingDuck, and PeterBaron, I would defer to them. They have a much longer history than me with a CB1100. My only claim to fame is that I love the CB1100 more than anyone else on this Forum.
