I bought a KB 100 model of 1987 good power and a decent pick up. It runs on and on for kilometers without any trouble. I always ride it at a decent speed of 50-60 kms per hour in the city as well as on highways. It has very nice stability compared to other 100 CC bikes.
One shortfall is the seat is to small so it becomes a bit uncomfortable for the pillion rider. Overall a good machine and avery good bike. My personal driving experience is very satisfactory as it has never breakdown but for once while on the highway.
I have been on my KB 100 travelling to Lonavla and Poona very frequently. It does become slow while driving on the ghats as it is an old machine but it has never faltered on the ghats .
On a fine road it can easily touch the speed of 80 kmph with the pillion rider but normally to keep my vehicle in good condition I always maintain a speed of 50 - 60 kmph.