Topic: Advancer marks explained please

[Chuck Hahn]

So this Ebay add shows the same advancer this 79 CB 750K has in it.  I assume the indicator points between the 2 close double lines with the timing light being used to set timing???   There is the letter "S" to the left of the double lines and the "F" to the right side..but the online manuals diagram is fuzzy at best to see how they say to set thngs up.  Thanks.

https://www.ebay.ca/itm/Vtg-1979-1983-Honda-CB750-Spark-Advance-Advancer-Assembly-A95/202077936027?hash=item2f0cc8999b:g:d7gAAOSwcFNZ0pRe&vxp=mtr

[MikeSimon]

I have the exact same problem with the marks on my CB1100R (essentially the same as on all other DOHC-4s)
Asked the question in several forums and no-one is willing or able to answer.

[Bodi]

Not sure what the little letters mean. With a timing light the spark should be at/near the F marks at low rpm, and between the advance marks at full advance (3000+RPM?). Advance timing is more important - over advance can cause pinging and not enough robs power - but unless something is worn they should both be right.