Thru Camshaft Breathing

robs ss

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During an idle moment I decided to check if the internal bore of the drive side of the camshaft of my 650SS in case it might be partially obscured with build-up, etc.
First I tried blowing into it, from the drive end - no luck, it seemed to be totally blocked
No problem I thought so I tried digging into it with bamboo cooking sticks but found it was still blocked
"Well I'll drill that crap out" I thought and started with a 3/16" bit
I was concerned when metal swarf came out so shone a torch down it only to find... it was completely blocked with solid metal - never was hollow from the DS lobes to the "breathing" holes
No wonder "cam breathing" Nortons have such a bad reputation for leaking oil!
I wonder how many other 88s, 99s, Manxmen, 650ss, Atlas and Mercuries out there are suffering from leaks thinking their breathers are working???
I am going to fit a breather (a la Jim Comstock) at the lower rear of the crankcase but thought I'd let others know what I'd found
Photo of the cam ID below
Cheers
Rob
 

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Were any of them hollow for the full length? I thought they breathed through radial holes near the breather end.

Ed
 
You're correct Ed
Mine is not hollow, however, from those radial holes to the breather (LH) end, as it should be - so could not have ever breathed
Cheers
Rob
 
Ed
Re-reading my original post, by "drive end" I meant engine drive side not cam drive.
Sorry if I caused confusion
Cheers
Rob
 
Hi Rob,
That is what threw me off. No problem. I'll need to check the new camshaft for my G15 build. This info is definitely a good heads up.

Ed
 
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