Motorcycle Repair: Carbon in engine, air fuel mixture, fuel additive

Question
I took off my carbs for cleaning and repair.
I noticed that I could see the inside of the motor of my 1978 honda cb400.  It was black with carbon.  What should I do? Can I spray carburator cleaner inside the cylinder head to get rid of the carbon?

Answer
Hi Terrance,

Leave the carbon there. Do not spray carburetor cleaner into the cylinder because it will contaminate engine oil.

Get the carb's air-fuel mixture adjusted properly to where the spark plugs are burning themselves clean. Use a fuel additive to aid in removing the carbon. With carbs tuned right, the carbon will not continue to build up and may eventually clean away existing carbon. Heavy deposits may require disassembly to clean.


Respectfully,
Mark Shively