Hello everyone.
I'm currently on my first big project. a 1990 limited edition bandit 400-Z (the top faired one). The main issue is that I found the oil sump to be full of fuel, an issue I this can be put down to the fact that the bike has been converted to gravity fed fuel system and the tap has been left on potentially allowing the fuel to get into the chambers. So I'm gonna service the carbs and maybe replace piston rings. The issue I'm having is that all the manuals I can find only cover the bike made after 1992 (when the engine was downrated). Does any one know the physical differences between the 90 an 92 engines? e.g. same carb jets and servincing specifications etc...
Thanks for any help offered.

There is a manual on this site that covers the early bikes.
Service date is the same as only a few parts, cam, ignition are different.

Forgot to mention we had it running - before we found the fuel in the oil and the engine maked one hell of a rattle (enough to drown out the yoshi can) Could simply be down to the oil being the wrong viscosity or is it morelikley that the fuel/oil mixture has wrecked the engine/ caused excesive wear etc...?