DOHC Ignition CB900/1100F


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EMS
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DOHC Ignition CB900/1100F

Post by EMS »

I am working on a friend's CB1100F and I am trying to set the ignition timing. I do not understand the directions in the original service manual. It talks about a "F 1-4" timing mark which I cannot identify.
The marks I see on the pulser/advance plate are: T, I, II and S. Which one do I align with the mark for a static setting?

steve murdoch icoa #5322
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Re: DOHC Ignition CB900/1100F

Post by steve murdoch icoa #5322 »

Mike, are you still an 1100F site member?
http://www.cb1100f.net/modules.php?name ... ming+marks

EMS
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Re: DOHC Ignition CB900/1100F

Post by EMS »

Steve, don't think I ever was and probably will not be. 8)

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SteveG
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Re: DOHC Ignition CB900/1100F

Post by SteveG »

Mike,

The 1-4 and 2-3 marks are hard to see. The are stamped below the "T" marks. You can just see the tops of the 4 and the 3 in the picture. The 4 is red, the yellow 3.

Steve

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82 CBX, 82 CB900F Project, 81 CB900(985)F, 79 CB750(810)F, 06 Wee-Strom

EMS
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Re: DOHC Ignition CB900/1100F

Post by EMS »

Thanks, SteveG. This will tell me which side to use when the pulser is on 1,4 or 2,3.
It still does not anser my question which timing mark - S, II or I - do I lign up for static adjustment. These marks are "before" ( in direction of rotation) the T mark

I am assuming, it is the "I" mark, which is closest to the T mark. The others are further ahead of the T mark, i.e.: more advanced, thus to be used at higher rpm.

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Re: DOHC Ignition CB900/1100F

Post by SteveG »

Mike,

Was reading up at cb1100f.net and stole this pic:

Image

Also learned the "F" mark = Fire, and the "T" mark is for TDC.

Steve
82 CBX, 82 CB900F Project, 81 CB900(985)F, 79 CB750(810)F, 06 Wee-Strom

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Re: DOHC Ignition CB900/1100F

Post by EMS »

Thank you, Steve!

Following that explanation, would the "S" mark be the "1.4 S-F" mark then?

Here is my confusion:
The manual says to set the static ignition timing at the 1.4 S-F mark. This mark is the furthest advanced from the "T" (= top dead center) mark.
When running, the advancer works against the springs and advances the ignition even more...??? or doesn't it??

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Re: DOHC Ignition CB900/1100F

Post by SteveG »

I have never really worried about the exact spot of where the index mark "tip" aligns regarding the advancer. The manual says that "The timing is correct if the narrow projection of "1-4" pulse generator aligns with the rotor tooth."

I do that, and if there is pinging, I slightly retard. If it runs good, leave it.

Steve
82 CBX, 82 CB900F Project, 81 CB900(985)F, 79 CB750(810)F, 06 Wee-Strom

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