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Author Topic: Cam Shaft shells scored/marked  (Read 698 times)

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Offline Roadrage23

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Cam Shaft shells scored/marked
« on: September 29, 2014, 02:09:25 PM »
Hi Everyone,

I'm currently restoring the engine on my CB750F1 and have noticed scoring on my camshaft shells. The camshaft is in good condition and the engine has done 37'000 miles on the clock.

What do you guys think? Is this acceptable?

Regards,
Roadrage23
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Offline flybox1

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Re: Cam Shaft shells scored/marked
« Reply #1 on: September 29, 2014, 02:49:19 PM »
I'd reuse those...
just be sure to put the caps back on the same location they came off.
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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

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"Knowledge without mileage equals bullsh!t" - Henry Rollins

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Offline Roadrage23

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Re: Cam Shaft shells scored/marked
« Reply #2 on: September 29, 2014, 02:53:04 PM »
Hi Flybox1,

Thanks for the quick reply... I was hoping for that answer  ;D!

Regards,
Roadrage23
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Offline iron_worker

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Re: Cam Shaft shells scored/marked
« Reply #3 on: September 29, 2014, 03:01:57 PM »
Ya they look decent to me too. The bearings are just aluminum so they can get marked up pretty easily.

IW
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Cam Shaft shells scored/marked
« Reply #4 on: September 29, 2014, 06:48:36 PM »
Those are fine. Keep the oil and filter changed to keep the microscopic buggers from heading up top.
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As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Don R

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Re: Cam Shaft shells scored/marked
« Reply #5 on: September 29, 2014, 09:13:27 PM »
I like to use a little assembly lube so they are good until the oil gets there.
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Offline martin99

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Re: Cam Shaft shells scored/marked
« Reply #6 on: September 29, 2014, 10:59:11 PM »
Quote from: Don R on September 29, 2014, 09:13:27 PM
I like to use a little assembly lube so they are good until the oil gets there.

Top tip.

+1 on re-installing, I've put worse than that back in!
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Build threads:
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TRIBSA http://forums.sohc4.net/index.php/topic,160296.0.html

1977 CB750 F2
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Offline trueblue

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Re: Cam Shaft shells scored/marked
« Reply #7 on: September 30, 2014, 05:40:46 AM »
A groove or score is acceptable, it will only hold more oil. What you have to look for is a lump, these cause clearance  issues. What you have there looks fit for service. ;D
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Offline garyS-NJ

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Re: Cam Shaft shells scored/marked
« Reply #8 on: September 30, 2014, 10:19:30 AM »
mechanical failure resulted in one trashed rocker holder (and a trashed cam & caps) in my 1978750F3 but luckily I have a basket motor with a nice cam and rocker towers but no cam journal caps...  UGH, everywhere I read the caps must be matched to the tower.  Is this because of the smaller inner journals and is there anything I can do besides buy new/used towers??
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Offline flybox1

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Re: Cam Shaft shells scored/marked
« Reply #9 on: September 30, 2014, 10:50:37 AM »
ideally you want them matched so they continue to wear at the same rate.  new caps, or the same caps put in a different location, will see accelerated wear on the cap and the cam.
My F3 valve train was in buckets when i got it.  My journals and caps were all just lightly worn.  I fit them properly to the towers (look for the tapered end of the cap), and lubed them up well during assembly and break-in. 
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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline Roadrage23

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Re: Cam Shaft shells scored/marked
« Reply #10 on: October 01, 2014, 11:12:33 AM »
Hi Guys,

Thanks for all the replies, I will reuse them and use the appropriate assembly lube  ;D.

Regards,
Roadrage23
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