Can someone provide OEM cam specs?


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Syscrush
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Can someone provide OEM cam specs?

Post by Syscrush »

Hey all. I've seen the lift info for the different years of intake and exhaust cams, but I'm having trouble coming up with the following specs (needed for both intake and exhaust):
  1. Duration (advertised or @1mm or @0.050")
  2. Lobe centerline
  3. Open and close time in crank degrees
Is this documented somewhere? Any info or pointers would be much appreciated.
Phil in Toronto
A cool guy deserves a cool bike, a dork needs a cool bike...
Pics of Perry, my '79.

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bobcat
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Re: Can someone provide OEM cam specs?

Post by bobcat »

Phil, if I was at home I could send you all that but I don't have it here on this computer.
Surely someone on this site has it. IMO the best cams to use are 81-82. Better yet degreed
to 103in.- 105ex.
Bob
82 CBX, 81 CBX, CB1100F, 79/82 CB900F (avatar)

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Syscrush
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Re: Can someone provide OEM cam specs?

Post by Syscrush »

Thanks a lot, Bob.

I'm not actually concerned with comparing or finding the best - I'm trying to find the necessary parameters to put into some modeling software to get some insight about my awful midrange. I'm pretty sure it's due to the very short primaries and the 6-2-1 design of the pipe, but some analysis would help to confirm or deny that hunch.
Phil in Toronto
A cool guy deserves a cool bike, a dork needs a cool bike...
Pics of Perry, my '79.

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Jeff Bennetts
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Re: Can someone provide OEM cam specs?

Post by Jeff Bennetts »

From my notes, the specs should be here in the forum somewhere, search and verify, this is all I have.

'79 Lobe Height
Intake - 37.30mm-37.46mm
Exhaust - 37.50mm-37.66mm

'80 Lobe Height
Intake - 36.80mm - 37.06mm
Exhaust - 37.00mm - 37.16mm

'81-'82 Lobe Height
Intake - 37.00mm - 37.16mm
Exhaust - 37.50mm - 37.66mm

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Syscrush
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Re: Can someone provide OEM cam specs?

Post by Syscrush »

Thanks, Jeff. Any ideas on how/where to find the duration and timing info?
Last edited by Syscrush on Mon Feb 19, 2024 1:45 pm, edited 1 time in total.
Phil in Toronto
A cool guy deserves a cool bike, a dork needs a cool bike...
Pics of Perry, my '79.

JoeInTUS
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Re: Can someone provide OEM cam specs?

Post by JoeInTUS »

Is this what you are looking for? Shop manual chapter 1.
IMG_0301.jpeg
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Joe S
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Syscrush
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Re: Can someone provide OEM cam specs?

Post by Syscrush »

That looks great, thanks!

So, if I understand correctly, duration @1mm lift would be:

5+180+40 = 225 degrees intake
40+180+5 = 225 degrees exhaust

Is that right?
Phil in Toronto
A cool guy deserves a cool bike, a dork needs a cool bike...
Pics of Perry, my '79.

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