Renovo bike frames are coated in 4 to 6 layers of clear coat finish. This is the same top coat product that goes on your car at the factory. We use Sherwin William Products called "Finish One". It keeps the wood and the environment completely separate. You no longer have to treat the wood bike as something different. You aren't riding around on a piece of furniture. Consider the wood completely protected in an acrylic coat.
Four different components make up the finish. First, we put on a vinyl sealer, made up of two components. After drying, this sealer coat is flattened. Then the decals are put on. On top of the decals, we toughen them by putting on a few coats of cyanoacrylate, directly over the decals only. This is like putting a glass protector over the decals. There is nothing worse than a scratch that takes off a piece of the decal, and this coating protects them from almost any abuse.
Then 2 to 4 coats of protective clear coat go on. We aim for a semi-gloss finish, but can buff to full gloss, or flatten to satin or matte. In fact, you can do this too with a little instruction.
Repair is very easy, but does take some practice and skill. Any scratches, dings, dents, or gouges can be filled with the same cyanoacrylate that we use to harden the decals. If you aren't familiar with this type of adhesive, Krazy glue and Supper glue are cyanoacrylates. But don't use those unless you have to. There are many good ones, and you can find them at the woodworker superstores Rockler and Woodcraft. The very best I've used, and the one I use in-house is Glu-Boost. Get the "flexible fill and finish" product. And get a can of activator. You can get a perfect finish repair with Glu-Boost. Glu-Boost was designed for guitar repair. I've found it to be perfect for wood bike frames too. I'd suggest you watch the videos on the companies website before you start, and then practice on a scratch on your desk or chair. For small spots, put a drop of the product directly on the scratch, and spary with activator. For broad flat finish touch ups, spread the Glu-Boost on with a paper towel or cotton rag. Use only a few drops, and spread it very thin. Spray, and then flatten with fine sandpaper. Repeat, repeat, repeat. For the last coat, do not sand and it will stay glossy. Or sand with something very fine (steel wool, scotch brite pads (kitchen sink)), to take off a little of the gloss.
If you have put on too much, use a safety razor to scrape it down. Cyanoacrylate glue is so hard, that if you put too much on, you'll have something like rock or glass to sand. Scrape it instead until you get close to your final level, then sand before recoating. Each coat can be done in a matter of a few seconds when you get good at it. Get the glue the way you want it before you spray with the activator, to keep the finish thin. And an important tip. Keep the area you are working on level or the glue will run.
If you have had success on practice wood, move on to the bike. Again, keep the area level that you are working on. Put it on very thin so you don't have to work the surface back down.
You could refinish your whole bike with cyanoacrylate, but it would be difficult to get a good even surface with even sheen. Use it mostly for repair.
For a full refinish, you should remove all of the original finish. Then rather than using our clear coat products, you can finish with anything you are familiar with. Even oil. Consider anything used in marine environments. But don't use oil if you might put a clear coat or acrylic coat on top of it.