Motorcycle Repair: Engine, octane gasoline, cylinder compression

Question
I just acquired a 1983 hondacb750sc nighthawk with 30,000 miles. I had some help from someone with more knowledge of bikes get it running. Cleaned out the carbs, instaled new plugs and got it to run but he says that he hears what he calls a knock when the bike is revved up is this bad engine or is it something simple. This is first bike so looking to get it up and running .Any help would be greatly appreciated.

Answer
Hi Richard,

I cannot diagnose sounds via the internet.

I suspect the knocking sounds are pre-ignition detonation. If so, the problem may be simply using higher octane gasoline.

It should be known that this model should run well on regular unleaded gas.

Check cylinder compression to learn the condition of the engine.

I return tech information files by email. There was no email address with your question as requested and explained in my instructions.

Respectfully,
Mark Shively