Topic: Pamco timing cb550

[Kevino]

What marks do I use when setting the timing and at what ram?

[Scott S]

 Set it at the 30 degree mark, between the blue and green lines, at ~2500-2800 RPM. Don't worry too much about what you see at idle.

[gwallis]

I don't get it???

Are you not supposed to time the CB550, with any electronic ignition, at the 'F' mark at around 1,500 RPM's?

[flatlander]

no, at full advance as scott says. the instructions for your ignition should also describe this, at least mine did for a boyer.

[gwallis]

Does this apply to other bikes with Pamco ignitions?  I also have a 1973 CB750 with a Pamco that has some timing problems...this might be the thing that helps.

[Scott S]

 IMO, it applies to all the SOHC4's and any ignition. You spend most of your time riding with the timing at full advance. Set the timing to be proper there and just "live with" whatever it is at idle. It's not just a Pamco thing.

[gwallis]

10-4

[Kevino]

i must not be doing something right because my bike will idle fine but under a load it runs like poop! spitting, sputtering, and almost like a back fire. i've got a 650 cam, delkavic full exhaust, pod filters and the carbs are jetted with 110 mains and 40 slow. i just rejetted yesterday afternoon, thinking that was maybe part of the problem, but no change at all. any ideas?

[gwallis]

Kevino,

I am not an expert on this subject, but I just went through get my 1973 CB750 running properly with Delkevic Headers and an air box from Cognito Moto.  The bike was so lean that I needed to up the main jet to a #132 and have the air screws turned 1/4 out from being seated.  Reset the timing via full advance and now it runs great.

The best way to see if the bike is running lean is, when it starts to stumble, engage the choke and see if the engine regains power.  If so the bike is lean and needs to have a larger main added.

Just my thoughts on the subject.... I am not an expert!

[PeWe]

Full advance at specified rpm does not rule out correct at idle. My CB750 got full advance way too early. I searched here and understood the advancer springs were too sloppy. Followed Hondamans description, cut 1/2 wound on each spring and reshaped the springs looking good with a plier.
No problem with F  aligning to case mark at idle (1200-1400rrpm, not lower to ensure oil on cam and rockers) AND full advance at 2600-2700 rpm. This was with a Pamco ignition. Later tried Dyna-S and finally TEC OEM points with Hondaman ign module. All OK.
I adjust at idle and see when full advance will happen. OK for me not before 2500 rpm

Correct ignition setting at idle and full advance when it shall is  not impossible.
Wrong responce at 2000-2500 will cause problems when taking off and in the city.... at least for me