Motorcycle Repair: timing, degree timing, spark advance

Question
QUESTION: Hi Mike.  I've got a 91 FLHS that's started pinging when pulling under load, like going up a hill.  It also doesn't seem to have the power pulling a hill as it did before.  I checked the timing.  It was off, so I adjusted it, but it didn't help with the timing.  I finally adjusted the timing by trial and error until I got the pinging out.  It had good power pulling the hill, and didn't ping. Now, though, it coughs out of the carb at idle and sometimes when I take off.  I don't know what all you need to know, but it has an EV3030 cam, S&S heads, S&S carb, and Dyna S electronic ignition with mechanical spark advance.  Got any ideas?  thanks Bill

ANSWER: What octane fuel are you running? What degree timing are you running? What is your compression?
Mike

---------- FOLLOW-UP ----------

QUESTION: I'm using premium fuel, I think 92 octane.  When I set the timing with the timing mark on the flywheel, it would be 35 BTDC, but it pings there.  I'm not sure about the compression, but it had a top end job done about 2,000 miles ago, and I'm sure it's fine.

Answer
To stop the pinging you can retard the timing a little, which should help. Since you stated that you seem to be losing power, that wouldnt have anything to do with the timing, unless it was way off. Sine the timing is direct drive off the cam, it should change over time, unless it is manually changed. Even though you had a top end done 2000 miles ago, I would still do a compression test. You might have a scored piston or cylinder, which would cause the loss of power.
Good luck and happy riding
Mike