Topic: Ignition table for cb550 ?

[Harald F]

Hey. 

i know there is little adjustability on the stock ignition system.. but what ignition values are the more modern electronic systems running on a cb550? 
What is the ignition advance at idle? what is it at higher rpms? 

Are any of the systems so advanced that they adjust for load? or just rpm? 

Soon to be running a cb550 using a fully adjustable fuel / ignition system and have no idea what ignition advance to aim for to get it running as most of my experience is with 16v turbo 4 syl car engines.

[scottly]

This is a very complex question. As far as I know, none of the "modern" systems accommodate a Map sensor, although some may have an input for a pressure switch, which toggles on and off at certain levels?
The initial timing (idle) depends on the compression ratio of the engine; a lower compression ratio can use more initial timing. The amount of RPM induced advance depends on how much boost the engine makes at a particular RPM.
With a positive displacement blower, the boost is more directly related to RPM, while a turbo's boost increases with load.

[Harald F]

A good starting point for me would be to figure out what range of ignition advance is normally used on these engines when tuned in a naturally aspirated situation. we will do dynotuning with knock monitoring, and from experience with boosted car engines lower the advance a bit depending on boost and rpm + throttle position.

I think i found that the dyna s 2000 ?   has a 20 or 25 degree span of timing, with a selectable rpm for "full advance" .
It would then be 15 degrees advance at idle(seems normal to me coming from cars too)  and increase to 35, or 40 degrees advance at high rpm.

Does this seem to agree with timing numbers used by people on here?

If so, i will start with a base map, running 10-15 degrees at idle, and 30-35 degrees up top, and gradually decrease the timing a bit depending on boost(load). 

Im guessing there is a bit of power to be had for NA engines too if you could control ignition like this?

With the blower boost also varies a lot with throttle opening, so having throttle sensor, and map sensor will give me the best possible chance of having the correct timing for any situation (read as..  preventing melted pistons)

[kmb69]

The Honda CB500-550 shop manual states 5°-30° for the stock ignition timing.

[Ilja]

I have an ignitech ignition with map sensor on my turbo..
I pull timing according to rpm and boost pressure... this way I can tune out ping in the range where its necessary.

Its from czech rep.. fully programmable with laptop.
Pictures are somewhere in my topic.

Base is 10 degrees. Then rising to 30 at 5000rpm and 33 at 9000 rpm.
I pull to 27 degrees at 10psi, 25 at 12psi and 22 at 15psi.
5000-7000rpm is sensitive.

(Cost around 160-190 euros with all cables and map sensor.
You need to retrofit pickup sensor and wheel from a newer bike..)