Topic: Timing....question for Dave500 and others...

[fendersrule]

So I timed my CB750 a few months ago using a strobe light (after setting the dwell on the points). When I timed it by strobe, I did it at idle.

So today I hook the strobe up to it, and 1-4, and 2-3 are perfectly dead on the F mark at idle (1100 RPM). Yay, no change.

When I advance:

1-4 is dead on the last advance line.

2-3 is a little bit after the advance last line.

Put the tools away and ride?

[fendersrule]

Playing away a little more:

The 1-4 plate (the large one) is all the way justified, and when advanced it's directly on the last advance mark. There's no more adjustment that I can do.

I changed the position of the 2-3 plate (small one) to where it hits in the center of the advance marks.

I guess now is the time to put the tools away. This is the first time I strobed it to the advance marks and disregarded the idle "F" mark.

Time to go out for a ride,

[Nic]

C'mon Dave, I'd love to hear the answer to whatever the question is

[dave500]

just strobe them both to the full advance marks and forget about the idle,itll be on full advance all the time anyway,make sure the mechanism is clean and smooth.

[fendersrule]

Dave,

When you say advance marks, there are two. Are you saying anywhere in between them is where it's correct, or do you try to get them to the very last mark? Is having both sides exactly the same important?

The mechanism is very clean and smooth. It doesn't bounce at idle, nor does it bounce around at advance.

[dave500]

having them the same is ideal,run as much advance as you can without pinging.

[fendersrule]

Ah ok....I can probably "tweak" the right plate a little bit more to get it a tad bit more advanced so that it will match up with the left side, which is directly on the second line.

No pinging yet...though I use premium fuel.

I'm not really experiencing or feeling and performance gains doing this, but it's fun to be nitpicky!

[lucky]

My opinion is different.

Static time the engine and forget using the strobe light.
If you do use the strobe, the mark should fall between the two lines.

Dynamic timing is when the engine is over about 2,000 rpm.
BUT you want it to idle correctly too.
Most of the time you are not revving it over 2000 rpm around town.
And even on the freeway it only goes over 2000 rpm when you then shift into the next gear anyway.
As long as the advance mechanism is not frozen up, just do not worry about it.

[dave500]

if your not over 2000 rpm around town your not riding it correctly!

[fendersrule]

My opinion is different.

Static time the engine and forget using the strobe light.
If you do use the strobe, the mark should fall between the two lines.

Dynamic timing is when the engine is over about 2,000 rpm.
BUT you want it to idle correctly too.
Most of the time you are not revving it over 2000 rpm around town.
And even on the freeway it only goes over 2000 rpm when you then shift into the next gear anyway.
As long as the advance mechanism is not frozen up, just do not worry about it.

Not really sure I agree Lucky. A CB750 pushing highway speeds is going cruising if not easily surpassing 3,500 RPM easily. On the interstate it's going to be 4,500, or around.

Around town I am definitely reving it over 2000 RPM quite a lot. Even my "cruising" RPM when I am done with shifting is probably over 2000 RPM. Hypothetically, let's say that my cruising speed is just at 2,000 RPM. That would mean that I'm definitelly in 5th gear doing 35-40MPH. If I'm cruising at such a low RPM, then I wouldn't expect performance to be on hand without down shifting a couple gears.

Timing it to the advance marks didn't create any difference in idle for me....

My LH plate (1-4) is already maxed out in movement, so I probably need to adjust the points dwell if I wanted some more adjustment to back it off between the lines. Right now it's on the last advance mark. The RH plate (2-3) is pretty much in between the lines right now. It's probably good enough for now, but I'll play around with it some more...

That is until more people chime in and say between the lines IS BETTER....

[Deltarider]

Dave is right. Advance as much as can without pinging. I have best driveability when a bit more advanced than the right line of the two. Bear in mind in those years Honda had to take into account the poor quality gasoline in some markets and therefore had to be conservative on the advance. Dave is right again when he states that driving around town near 2000 rpm you're not riding it properly. Your motor will not be happy and I find Lucky's suggestions a bit silly. Make sure yo have the right timing at full advance and accept whatever the timing at idle is.

[fendersrule]

Cool! I'll move 2-3 closer to the right advance line.

Then it should be perfect!