Motorcycle Repair: pinging, ngk spark plugs, modual

Question
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Followup To
Question -
hello..& thanks
my 98 flht with 1340cc eng, a screemin eagle kit.(dealer installed)..ie heads, se 57 cam, adj se ingition mod.
coil ect. 0-3k rpm goes well, but under load
it pings considerably and hi octane fuel helps
but the problem still is there...the moduel
settings are...1-off,2on-3-on,4-on,5-off, 6-off
is there a easy way to set the  ingition moduel.settings?
rather than trial & error...
Answer -
It is not the ignition modual that is the problem.it is the final drive gearing. It needs to be changed. the cam was not a very good choise. and I do not know what exhaust system you are running?. I never use Screaming beagle ignition moduals. I use only Compu-fire ignition moduals. Johnny 602-705-7474
"ok"...johnny thanks!..please explain...changing the final drive gearing?..I have open mufflers...but the
rest up to the heads is stock..exhaust...The..final drive gear..?..please explain in detail and make a reck-o-mendation..and your reasoning to the cause the need..do you mean the rear belt sprocket? and the small sprocket in the engine case...mine are stock
the pinging is at 2500k at 35 mph under load ..(up-hill) recomend a set up...part#s or at least some specs I'll do the rest! thanks!again! wind at ya back!

Answer
Change ot the motor sprocket. You have a 25 tooth motor sprocket. Harley Davidson sell a Primary gear change kit for 135.00   it comes with a 21 tooth engine sprocket and a primary chain. Takes about 1.1/2 hours to change out. this will put the bike in a lot beeter rpm and will talk the load off the motor and will stop the pinging. also go with some NGK spark plugs # BPR8 gaped at .040" and torqued to 18 ft lbs. You have a 3.15 final drive and you will now have a 3.78 final drive. You will love this kit. Your bike should be riding at 3,000 rpm to 4,000 rps at all times on the free ways. Johnny  602-705-7474