Topic: 1975 CB750FO timing mark

[Dave B]

According to my manual the timing should be set on the F mark just as points are about to open.
The bike is not firing when set up on the mark directly under the F.
I can see two marks prior to the F mark.
Am i on the right one in the photo?
Cheers,
Dave

[david 750f]

T is Top Dead Centre (Center)
F is “fire” for the ignition timing.
The two marks to the right are the full advance (2500rpm+) marks.

[Dave B]

Thank you
Just thought id check myself
running out of ideas
cheers
Dave

[ekpent]

 Set the tappets/valves on the T mark also but I bet you knew that already.

[Dave B]

Thank you
its good to have stuff confirmed as correct when bike won't start
cheers,
Dave

[bryanj]

Points gap needs to be 0.35mm(14thou) before setting timing BUT moving the plate alters the gap and altering the gap moves the timing so you have to "juggle" the two till both gap and timing are spot on

[Dave B]

Thank you
should i check the timing chain tension before or after i check the tappets?

[Bodi]

Doesn't matter. Set in & ex tappet clearances with their piston at TDC compression (there are other ways but going one cyl at a time with each set there is simplest and most foolproof). The cam lobes are far from where they could lift the valves even with way more timing chain slop than is possible.

[Dave B]

thank you
busy day today
cheers,
Dave