Camshaft running in procedure confusion

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Very few bikes of any brand were broken in by owners using cam break in methods. So I don't use that as a reason in most cases
I resemble that remark. I think my Norton was broken in using the old hot rodder method. Beat the hell out of it from the get go. If it's going to break, it's going to break right away. They sure run good when they are fresh. I don't know how well that method works for longevity.

I have an 80's batch 2S cam, might even be a 2X cam, damn memory is failing me. Only thing I did was shim it off the timing side case. I essentially did everything wrong, but the motor is still running, and doesn't seem to lack for much. The followers are ringy ding dinging now, so I don't know what's happening down below. Oil doesn't come out clear on oil changes, but it doesn't have metal flakes in it either. 7500 miles. Will see what happens when I hit 8000.

I should invest in a bigger garage heater. I have a feeling a winter rebuild is in my future, if anything said in this thread pans out. :)
 
Yes

Another observation/surprise came after opening the crankcases. Both outer race's Superblend dropped right away from the cases!!! No heat applied to the cases, nothing!! Upon inspection, I can't confirm a lot of bearing spinning in the case. May be a little bit, but no big shinning surface in the case. Is this situation common?
More common than you realise.
Dunstall was the first to use a pegged bearing, it was a relieved outer bearing that took a drilled and tapped washer.
 
Yes, but I am guessing that any motor that has one of those cams in hasn't just completed 102,000Miles?

Those cams were around over 40 years ago, if you have one it will have been sitting in a low mileage bike just waiting to bite someone.

Not saying you can't have bad cams today, but cam problems I and most others have had since 2015 are not down to these cams, something else is at play!
Mine has back in the early 80s I got my stock 850 cam built up and regrind to 2S profile and I am still running the same cam today with about 160k mile on it, Ivan Tighe here in Brisbane did the work all them years ago and my lifters were reground at my work when working in maintenance and in the machine shop.

Ashley
 
Don't confuse cam break in with engine break in; they are totally different.
When one rebuilds an engine and installs a new cam at the same time, both can be done without the 2500rpm for 30 minutes routine. That is what my example was about. I've never had a cam go flat doing it. I've only changed the cam in a Norton once though, so small Norton sampling. Other vehicles with flat tappet cams many times.

Not recommending my method by any means. It could result in an out of bounds penalty.
 
Mine has back in the early 80s I got my stock 850 cam built up and regrind to 2S profile and I am still running the same cam today with about 160k mile on it, Ivan Tighe here in Brisbane did the work all them years ago and my lifters were reground at my work when working in maintenance and in the machine shop.

Ashley
So you have the original cam core, but not the lobes!! Which were the problem. You fixed it!
 
Like I said, I had the all my problems with the 1975 cams, but I do have an early 2S cam that came in a parts bike I brought that suffered a worn lobe. I have worked on a few customers MK3 bikes that had full lifts so it can be hit or miss.

You can see the rocker arms do not move to full travel and the engine sounds like a bucket of bolts rattling in a can.

But when my MK3 ate it's second one, It was time for a full re work and a Web Cam #12. But even a mild Web Cam out performs the Combat cam with lower lifts and a better designed lobes.

To help the situation, I run oils with zinc in it, now.

Your experiences may be different. Your lucky.
 
'Micrometer Blue' is known to most of us and 'Engineers Blue' Dykem may well be a trade name, never heard it called that. It is simply a dye you put on metal parts for marking out ( coat a surface in it and make scribe marks as required for the part you are making, and you will be able to see them easily 'in negative' as the Blue is removed by the scribe.

Or it can be used for checking surface contact as in the case you are looking at, i.e. you put it on one part and check it is evenly transferred to the other when assembled and rotated. Carl is right to suggest that even if you do this test you may not see 200 contact between the tappet and the lobe, the contact track may reduce in width around the cam lobe, this can sometimes be seen in the wear patterns, most of us can ignore it as long as contact does not stop at some point because if it is the tappet is being held away from the cam! I have only seen this happen when the tappets are too tight in the tunnels or against the retainers (ref the fettling I mention later to correct this condition). But you don't need to do any trial assembly beyond tappets and barrels to confirm correct fit here, just make sure the tappets free fall to the point they are stopped by the retainers.

102,000 miles, quite something, but, what you haven't said is:

Is the motor now stripped and inspected?

Did the motor cover all of those miles with no impact between cam and tunnels etc? If so why suspect a problem now?

Is the cam you are fitting to the same spec as the one you are removing? If it will be a standard cam, why suspect a problem?

(Of course if it is high lift it is your responsibility to make sure there is no impact now, and if it is say a PW3 or 4S, or similar, expect a problem. You will need to create clearance at the mouth of the tappet tunnels through grinding. But this is nothing to do with the barrels meeting spec, it is due to modification from standard spec.)

Are you having the barrels rebored and fitting new pistons? Does the measured wear actually demand that? If not done yet, can the borer check the 'radial' position of the bores? Before and after boring!

(As an aside, why does 'radially out of position' sound like bullshit? Particularly without a drawing to indicate which radial we are talking about!! Which surface has been machined wrong?)

Have you confirmed the need for +0.020" tappets/followers through inspection and measurement?

(The last standard size ones I had from AN were actually several thou oversize and might well fit without the fettling I had to do on them to put them into the barrels, there have been discussions on here about that. AN will surely tell you exactly what they are supplying as a standard follower now, check out the discussions!!)

Are you in any way boring the tappet tunnels to suit the new tappets?

Rumour has it that at some point in the past, a certain supplier has allegedly provided customers with barrels that were scrapped by the manufacturer for not meeting spec. Guess which supplier that was? Don't be surprised if it is the one that is telling you that barrels can be out of spec!

Rest assured, again rumour has it, allegedly, whatever happens, in that supplier's opinion, it will be your fault!!
Steve, I have answered to your questions further in this thread.My new cam shows wider lobes than my original one. I'll check how the contact is done with the lifters. I'm afraid of having the lobes grooved like on Carl's photos...scaring for nothing???Also what is the ideal end play for the cam? Found nothing about it and how to shim as the only part showed in the part book is the chamfred washer
 
So you have the original cam core, but not the lobes!! Which were the problem. You fixed it!
No my stock cam lobs were still good and nothing wrong with them, I had the profile of the lobs built up and the 2S cam grind, I built my 850 motor to the Stage one high performance for road use when I built my motor for the Featherbed frame back in 1980, my workshop manual has the high performance section at the end of the book, remember this was back in 1979 when I planned this project so no internet in them days and was easier to get my stock cam built up and grind for my hot motor, Ivan Tighe was the best high performance cam build in AUS at the time, this took me 3 years of planning and building my hotrod Norton back then as for a year or more I wasn't working so money was tight.
I am still running the same cam after 41 years since it was build up and grind.

Ashley
 
Steve, I have answered to your questions further in this thread.My new cam shows wider lobes than my original one. I'll check how the contact is done with the lifters. I'm afraid of having the lobes grooved like on Carl's photos...scaring for nothing???Also what is the ideal end play for the cam? Found nothing about it and how to shim as the only part showed in the part book is the chamfred washer
I have only shimmed cam end play once! That was done to install an ex works Luca Rita ignition with a very early pick up that required the timing cover to be machined away. You had to be sure the steel reluctor piece fitted to the cam end did not hit the ignition pick up that it passed through, so you were concerned both with absolute position and float. I used shims from a John Deere tractor steering box, which coincidentally fitted! Shimmed central in the pick up and to about 0.015" movement was good to control the issue. Some other electronic ignitions may be sensitive to this, but most aren't.

Normally you would not expect an issue and I think cams are very rarely shimmed for end float. That is why there is nothing to refer to on the subject, mostly it's a non problem. The camshaft thrust washer (as you say the chamfered washer) and the cam bushes are the only parts that affects camshaft end float, it isn't that big of a deal for most installations.

Some people have left the thrust washer out on assembly, (or one of the 2 thrust washers used on 200,000 series 750s, which originally also had a tanged washer). That should show up quickly, but you would have to pull it all down again to rectify. But as long as you have the thrust washer in place and the sprocket is properly seated, the play you have is the play you have.

Yes, Carl's photo are scary, and I think you are going to have little risk of this happening unless the cam itself, or the tappets/followers are defective.

Mild cam profile suggests you won't be revving over 7000, maybe not much over 6000, that helps life hugely and trick stuff like lightweight valve train parts is not an issue, a good set of standard AN springs should keep everything in order.

Whatever you do, use a break in paste as has been said. Personally I use Graphogen, colloidal graphite, which is old school but great stuff. I have been using it since the '80s but more recently discovered Norman White uses it. But I am sure the Webcam product is good too. And make sure you use one of the oils that came out well in Jim Comstock's testing and change it regularly.

It has been well covered here to always keep the revs up when breaking in, but do it generally when warming up. If after break in it is taking a while to set up carb mixture screws, don't just keep it running around 1000rpm, blip to oil the cam regularly. Care, but don't scare!

I think it is great that you are able to retain the standard bore with 100,000 miles on it. Norman White told me some time ago that he thinks a huge number of barrels have been bored that didn't need it, and specifically he thought they were good for 100,000 or more.

I am not a professional, so don't have the equipment and spent a day fettling each pair of tappets, by hand! The bores were standard, and I kept them that way, thinking of the future! You now still have 3 oversize opportunities for your bores, but possibly none for the tappet bores! Don't let that worry you, I'm sure it isn't an issue.
 
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