Cams

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lwmcd1

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I've heard that there was a bad batch of cam produced that were improperly heat treated.
Is there a way to determine if the one I have aquired is one of those?
The only markings I see are
T22/9
sa inside circle then a 2.
I believe it came out of a 750 Atlas.
It's going in my 74 850.
Thanks,
Larry
 
lwmcd1 said:
I've heard that there was a bad batch of cam produced that were improperly heat treated.
Is there a way to determine if the one I have aquired is one of those?
The only markings I see are
T22/9
sa inside circle then a 2.
I believe it came out of a 750 Atlas.
It's going in my 74 850.
Thanks,
Larry
Click to expand...
Hi Larry,

The soft cams came in 850 Commandos. By the way an Atlas camshaft will not work in a ‘74 Commando as the tachometer drive is different.
 
Yep,
I just noticed that there is no tac drive on the one I have.
I've never had a tac that worked more than a few 1000 miles
so I don't bother with them anymore.
that being the case, can I use one without the tac drive or are there other issues?
 
lwmcd1 said:
Yep,
I just noticed that there is no tac drive on the one I have.
I've never had a tac that worked more than a few 1000 miles
so I don't bother with them anymore.
that being the case, can I use one without the tac drive or are there other issues?
Click to expand...

No place for an ignition
 
comnoz said:
No place for an ignition
Click to expand...
YooHoo!
I bought a set of 4 for $45 off of eBay.
They looked to be in very good condition.
I only need one.
Anybody needing one should let me know.
I'll be happy to share. the good fortune
 
lwmcd1 said:
All 850s or only certain ones?
Click to expand...

August '74 MKII - about 35,000 miles:

Cams
 
maylar said:
August '74 MKII - about 35,000 miles:

Cams
Click to expand...
I would bet the follower was soft and caused that damage -not the cam.

If you still have it I will buy it and test it for hardness. Jim
 
Last edited:
lwmcd1 said:
I'll let you know.
The photos seemed to indicate they were in good shape.
I'll know for sure when I get them.
Click to expand...

If you would like to sell the extras I will buy them. They can have any amount of lobe damage but the bearing journals need to be good. I will use them as cores for rebuilding. Jim
 
comnoz said:
If you would like to sell the extras I will buy them. They can have any amount of lobe damage but the bearing journals need to be good. I will use them as cores for rebuilding. Jim
Click to expand...
Sure,
I'll look at them when they arrive and let you know the condition.
They look very good in the photos but
I don't trust photos very much.
I would not try to sell anybody junk.
Especially fellow Norton enthusiasts.
They should be in in a couple of more days.
 
Jim,
I also have a boatload of other Norton parts.
Also, 3 sets of BSA cases A10.
And a few Misc Triumph parts.
At's all just taking up space that
I don't have.
I'll try to upload some photos if I can figure out how.
Well shoot, I can't figure out how to upload photos.
 
You would need a photo hosting site to upload photos unless you are a paid member here.
 
comnoz said:
You would need a photo hosting site to upload photos unless you are a paid member here.
Click to expand...
I'll look into a hosting site though it may be beyond my skills with a pc.
By the way, what would it cost to have one of these cams properly hardened for my use?
Also, I have the one from the atlas if you think you can use it also.
 
9
lwmcd1 said:
I've heard that there was a bad batch of cam produced that were improperly heat treated. I believe it came out of a 750 Atlas.
It's going in my 74 850.
Thanks, Larry
Click to expand...

You should have been in Paul Dunstalls shop in Well Hall Rd when he was having a clear out, there were at least race cams there that had the cam lobes completely worn away much worse than in p 9 – they were just scrap.

I would advise you to get the cams hardness treated, but this will not give you any information as to if it has been double hardness treated.
 
 
TBH, I've always attributed cam wear to improper break-in though I admit I've seen plenty of statements about "soft cams," including those from cam suppliers so clearly, it happens. But I still wonder if cam break-in doesn't play the major role, caused by wrong assembly lube and/or incorrect break-in after the engine is running.

I've often wondered what the factory "break-in" method was - if any. ;) If there was none, just engine assembly, then the cam break-in was just 'however' the purchaser first rode the bike! The "break-in" specified in an owners manual is not what is needed for proper cam break-in. :(
 
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