Ok, this may not be related or all, I profess complete ignorance and just want to know. Does retarding or advancing timing make the engine run richer or leaner? If so, which way does what?

 

The actual Air Fuel ratio of mixing air & fuel happens before the spark plug is fired. The Air/Fuel Ratio does not change when changing the spark timing. More COMPLETE or INCOMPLETE combustion can occur from changing the spark timing, but don't mix that up with the A/F ratio because that will remain the same.

 

I'm glad you asked TT. I'm no sexpert on this either but was told and can agree with this.

Spark can't lean or enrichen fuel mixture. It doesn't make an engine run more or less rich yet spark and fuel must work together in tandem.

When you retard timing you are pulling power and increasing the heat your motor.

When you advance your timing you are increasing your pulling power and decreasing the heat in your motor.

The issue is... the fine line you walk in between the proper retard and advance for power, heat and without knock.

Then there are different areas of your calibration that need more or less depending on the RPM range or what the bike is doing... WOT or idle, decel or temperature range adjustments.

Knock can be cause by timing as well as fuel. Once timing is properly set you must readjust your fuel. (VE's)

What I do know for sure... setting the proper timing is a royal pain in the butt and without a dyno it will take a very long time to get right.

 

I am trying to understand how the closed throttle spark table in the TTS would work. I think I understand that when you let go of the throttle or the bike idles that it goes into that spark for that particular RPM range. I just don't know what this does for a closed throttle event. I can understand what it does for an idle event, but not sure how the closed throttle benefits from adjusting this. This is a new table to me (I have previous SERT experience) and just can't get my mind right to understand this concept.

 

Closed Throttle is Idle. When the throttle is closed or the throttle body butterfly is at Zero, the IDAC is still bleeding air PAST the closed butterfly in order to allow the engine to run. You still need spark timing at Zero throttle position because the engine is still running.

(maybe I don't understand your question?)

 

Look at the JPG I attached. I am trying to understand how 1500-4000 RPM range matters. The bike is not in idle at that range.

 

So, my question is; Is optimum timing the highest degree of timing with out knock?

 

TT... remember this table uses a temperature range. 48*C = about 115*F. So, that would only make this table effective at cold idle or cold climate decel. The range on the table is about 3*F to 140*F.

I rarely use the closed throttle spark table. What I do know is, it can be used to reduce decel pop but this will also affect your spark at idle which could create heat at idle or could cause a rough idle to roll on, hesitation maybe the term I'm looking for. Again within that temp range only.

 

I've had many sleepless hours thinking about this. Again, I am no expert on timing but...

I believe many think so.

To me the optimum timing is a scale that makes your bike preform as you like, smooths your power ranges and rideability. If your timing doesn't create knock or will not cause the motor to run overly hot then you should leave it alone.

To continue to push the timing up degree after degree just to rely on the ION system to tell you there is knock is a crude method of discovery. A Dyno run with visible TQ and HP charts is the only "true" way to create a proper spark table to your build. I'm also a firm believer in leaving the "Adaptive Knock Table" alone.

 

Strange, because if operation temperature is greater than 200F, then I don't see much benefit in adjusting this table for decel popping. Am I wrong in this thinking?