Bicycles and motorcycles of all types are an important element in a model scene of Tokyo. This post is going to be limited to bicycles. Look at almost any random Google Street view scene of Tokyo and you are likely to see some bicycles. Fortunately there are several options available for N scale bicycles. I have not tried them all but here are the ones I have used.
TomyTec offers two sets which include both bicycles and motorcycles with riders. They are well detailed and painted. The riders are separate pieces if you want to use the bicycles as parked. Several of the other TomyTec building or scene sets also have bicycles included as part of a scene but they are separate pieces and can be used by themselves.
For bicycles without riders Gold Medal Models offers a set of 10 etched metal bicycles and a couple of parking racks. These have been around for quite a few years and are widely used in the US to model bicycles. Being etched metal they are quite thin and it can be a challenge to place a rider on one and have it look right. Also I felt that while they are the same overall size as the Tomytec models because of the thinness they just did not look right when placed together with the Tomytec models. I used them as parked bicycles in separate scenes as shown in the post Finishing the Green Max houses.
Sanki offers a set of 4 riderless bicycles that are of a paper stock. The handle bars are separate and I found quite difficult to attach to the frame and then very delicate. These models are undercoated black but can be painted. At 280 yen for a set of 4, these were the least expensive N scale bicycles I've tried.
What I've had good results with for parked bikes are these plastic models from Tomix. They come in two different styles and are unpainted except for the tires, seats, and baskets.
Because I don't really like the molded colors of these bikes, I end up repainting them starting with the frames. I've hand painted the ones shown in this photo but they could be airbrushed as well. After the frames are painted, I go back and touch up the tires with Floquil grimy black.
Here are two of my completed bicycles with some details added, mostly by painting. I do all this painting and detailing before removing them from the spue. By adding details like this, it is possible to make each one unique even if they are the same color.
I found that the sport model bike is quite delicate at the front and had best results by cutting that first, then the back, and last the bottom.
When compared side by side there is quite a difference in the sizes of the Tomix and TomyTec bikes. What I have been doing is using the Tomix ones as parked and the TomyTec ones as being ridden since those come with some riders that seem to fit OK.