hello , installed S&S 100" big bore kit on 05 88" twin cam., also 585 ez cams,ss carb,cam plate,oilpump,adj pushrods and dyno tyk programmable ignition mod. Have had pre-ignition noise 1/4 throttle then gos away. i have retarded ig module and rejetted carb.... any ideas where noise coming from and why? compression is 10.5:1 . all S&S says is have it tuned?? Can they do anything on dynometer in my case with carb? thanks Kevin .
Bike is 05 road king 13000 mi

 

Is the pinging occurring during a roll on acceleration in top gear? Does it do this when you down shift when under hard acceleration?

 

roll on acceleration pretty much all gears worse higher gears

 

Sounds like a lean tip-in or too much timing. I'd suggest properly reading plugs and going from there.

 

What octane gasoline are you using? If it's low octane, a higher octane may well take care of it for you.

 

That's top advice, take it. I like S&S stuff so much I bought an entire 107" engine with carb, complete with 585 cam, and have had it dynoed twice - once when new and later after an exhaust change. Get it dyno tuned - you'll be surprised how much different and better it is!

 

S&S and Mr Brown know what they are talking about. Why in the world folks do major engine work and never have it properly tuned in is unbelievable to me.

 

been tuning carbs for 40 yrs figgured could handle it