Pentium II overclock

I have a P-II 400 Mhz (100x4) and a MSI MS-6119 Mainboard.
The multiplier on the CPU is fixed, the mainboard supports busspeeds of 100, 103, 112 and 133 Mhz (and some lower).

I tried to overclock the CPU by ajusting the busspeed, but on every other speed then 100 Mhz (or lower) the system is very unstable and windows won't load, even on 103 Mhz (so CPU on 412 Mhz). I do this in the bios (Plug 'n play CPU)

I thought overclocking from 400 to 412 Mhz wouldn't be a problem at all, and had expected 448 Mhz would do fine too. Does anyone know why such a small speed-up causes instability? Could it have to do with the fact I didn't adjust the voltage (which I couldn't manage)?