Which vacuum hoses to plug when using a timing light?

[batever]

I have in my possession an old old timing light whose directions say to plug the vacuum hose to the carburetor when checking the timing with the timing light.

Well obviously the CB7 has no carburetor.

So do I need to plug up a vacuum hose, and if so, which one?

Thanks

[C91BLX7]

No just jump the blue service connector under the dash.

Thats so you get base timing with no advance.

[batever]

No just jump the blue service connector under the dash.

Thats so you get base timing with no advance.

Thanks, C91BLX7.

So when you jump the service connector, the ECU doesn't modify the timing according to RPM?

BTW, does anyone know why you had to block the vacuum hose to the carburetor in a carbureted engine when checking the timing with a timing light? I'm curious.

[N9netwoAccord]

Thanks, C91BLX7.

So when you jump the service connector, the ECU doesn't modify the timing according to RPM?

BTW, does anyone know why you had to block the vacuum hose to the carburetor in a carbureted engine when checking the timing with a timing light? I'm curious.

probably because they had vacuum advance back then

[C91BLX7]

probably because they had vacuum advance back then

Yup, his light says to disconnect the vacuum advance to the distributor, since we have electronic ignition, we do not have vacuum advance, its all computer controlled.

[accordztech]

probably because they had vacuum advance back then

your right!