I have a 95 GSR and I have been burning a moderate amount of oil (1qt/500kms) for the last year but recently I have noticed my rear bumper getting a black build up..... Is this because I'm blowing oil or do you guys think I am running rich... If I'm running rich, what things should I look at? Thanks for your help.

 

you could have black residue from a worn out cat. do a compression test to see if your piston rings are worn (would burn oil). running rich usually doesnt leave that much black stuff on bumper. your motor runs rich from the factory and if your fuel management is stock i wouldnt worry about it. new splark plugs, cap and rotor will help to burn off more of the excess fuel.

 

black is rich
blue is compression(rings or valves not sealing). there you go