Motorcycle Repair: i need help, bikebandit com, crankcase pressure

Question
i recently changed my air filter on my 93 gsxr 750 and found there was oil & gas in the air filter compartment. what causes that and how can i fix it? and the Trans casings on the left side witch holds the shifter in place is broken. is there another way to fix it besides replacing and what caused it to brake? thanks allot i really appreciate your time,though and effort in helping me solve this problem. what can i do?

Answer
Gary, these are not the kinds of questions that I really enjoy.. not Honda and not enough info.  The mileage, condition and history of the bike, as far as crashes, maintenance etc. are all useful pieces of the picture.

http://houseofmotorcycles.bikebandit.com/suzuki-motorcycle-gsxr750wp-1993/o/m623...
see GEARSHIFTING, CRANKCASE COVER, AIR CLEANER sections.

Oil in the air filter case could mean that the drain hose on the bottom of air filter case hasn't been drained for awhile OR there was too much oil in the engine and the overflow fumes/solids got pumped up into the air filter breather system OR the piston rings are worn out and the excess crankcase pressure is being routed into the air filter where it is suppose to be re-burned back into the motor again.. at least the fumes are.

Gas vapors could be there from blow-back through the carbs on acceleration. If you run the engine at various speeds the pressure waves from the exhaust system can push the fuel charge backwards at certain phases of throttle settings and rpms. To a certain extent that is normal, unless you have a carb with a high float level or perhaps a sticking float.

If I understand your question about the engine case, it appears to be full of holes to lighten the part and let heat out. If the transmission is hard to shift and/or the bike has gone down on that side, it would be easy to damage that casting part. If it is aluminum and in good condition, you can get a good welder to repair the cracks and reinforce the cover, where it is weak. If it is magnesium, it will melt down under a welding torch, but they may be able to TIG weld it, carefully. Parts break due to crashes, severe use, binding, poor design and neglect.

www.gixxer.com probably has more precise answers that this guy who specializes in old Hondas from the 1960-80s... Dive in here: http://www.gixxer.com/forums/

Bill MrHonda Silver