I need to buy a cam

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Well, it's now time for the dreaded cam replacment.
Where is the best place to get one? Which cam is best? The bike is a 75 mkIII. I would just as soon get everything that I am going to need from the same guys(cam, seals, gaskets, etc.)
Also, does anyone know if they ever made an interstate with the JPN colors on it?
 
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I won't try to give someone in the US advice on cam sources. Most of us have long despaired over the options on the UK market.

Nortons never catalogued an Interstate in "Flying Fag Packet" colours. I always had the impression that the "classic" silver with red and black striping was the Interstate alternative to the No. 10 colours on the Roadster.
 
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Why not quell the fellows' querry?....

JPS naturally refers to John Player Specials...a famous, but not really enjoyable way of killing yourself, and fags...not that it doesn't bring up visions of "oral fixation" and such....is a queer way the Birts have for refering to JPS's.
Not that we would pretend to assume there is any connection between the act of placing a JPN in the mouth and assorted activities usually asociated with the word fag in the US....but it makes perfect sense if you think about it. :wink:
 

ntst8

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On the CNW suggestion, I enquired about cams from CNW about a year back, below is Matts reply from then.

"I now only use WEB cam, especially the 12A grind. These are regrinds on your existing camshaft and WEB does a great job. One of the leaders in the industry. If you wanted to shorten your down time you could source another 'donor' cam and have it done, then just install when your engine comes down."
 
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just a quick question...
you speak of regrinding cams, is it posible to "regrind" transmission gears too? Can they be fixed once they start to howl, or is it a throw-away situation?
Thanks...
 
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hewhoistoolazytologin said:
Why not quell the fellows' querry?....

JPS naturally refers to John Player Specials...a famous, but not really enjoyable way of killing yourself, and fags...not that it doesn't bring up visions of "oral fixation" and such....is a queer way the Birts have for refering to JPS's.
Not that we would pretend to assume there is any connection between the act of placing a JPN in the mouth and assorted activities usually asociated with the word fag in the US....but it makes perfect sense if you think about it. :wink:

Hewho, I don't want to be to picky about the history of tobacco sponsorship in the UK (I was going to say "anal" but in this context, it doesn't seem appropriate :) )

JPS (John Player Specials) were the John Player brand in the black and gold packets used in the 1970s for formula 1 car sponsorship (Lotus to start with, I think). The brand was later used for sponsorship of the black rotary stinkwheel things so they were "JPS" Nortons.

The Red / White / Blue colour scheme which looked so good on the Monocoque and Space Frame works bikes was as a result of using the "No.10" brand. That was a bit down-market compared with the "Specials" Nothing like as down-market though as the pale blue and white colour scheme of Players No.6 which they used on the 1972 works bikes.

No.6s were probably responsible for me never becoming a smoker. One drag of those behind the bicycle sheds and I was an anti for life :)
 
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camshaft

Are we all done with the tobacco issue?. A good choice of camshaft is the PW3, designed by Peter Williams -- ex Norton engineer / racer, and supplied by Mick Hemming,talk to Mick and he will be more than happy to give advice on camshaft choices -- unlike some other Norton parts suppliers -- discussed previously on this site,Mick does not have a WEB site,phone # is 01604 638505, FAX # 01604 631838. Good luck. James
 
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The latest NORVIL cams are Chilled White Iron (I'm sure that's the correct material name) They are as hard as hell right through and hard wearing. Do not over tighten the rotor as you will crack the cam through the taper/seal spigot.
Been there got the lighter wallet etc.
Cash
 
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I put in an RGM stock cam 4 yrs ago (reputedly chilled CI but not sure) and made sure it and the lifters were well covered with both the red cam lube Norvil sells and some thick Crane Cams grease left over from my American car days. It was run in at 2500 rpm for 20 mins and after a strip this winter to do the mains there is little wear. That's with 11,600 miles on it and using Mobil 1 15/50 or Amsoil 20/50 synthetics which I am converted to. Not a big mileage I know but you read about cams going earlier than that. The break-in is one of the most important things you have to do, not that it will make a soft cam good but it limits initial wear.
I had the lifters ground which is a must. What you often find with the lower cost cams is inaccuracy. My RGM needed advancing 5 deg to get the intake opening right which puts the exhaust even further out (late) than it was with stock timing. The original "2S" cam the bike came with was a Fred Barlow (now deceased) special which had the timing of a stock cam with 2S lift. They do seem to vary. The PW3 cam is not known for it's low down torque, does need big clearances (noise) and as someone mentioned a while back made his Commando not sound like a Commando!
I was tempted myself.
 
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Here's a bit of lateral thought, (I'm full of rubbish like this).
I wonder if cam wear is caused by starting up on a dry sump (is wet sumping good?) and rubber covered cam chain adjusters keeping the chain quiet but allowing slack?
 
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Keith1069 said
made his Commando not sound like a Commando!

What exactly do you mean by this? Are you referring to the clatter of the valves that have a larger than standard clearance?

I have just put a 4s cam in mine, and had conflicting advice as to whether or not to put heat insulating washers under the exhaust valves. On consulting three experts, two said yes and one said no, so I have put a heat insulating washer in place and of course being an 850 washers under the inlet as well. I just hope it doesn't cause the exhaust lobes to wear out too quickly. I did also check the clearance from coil bound which was acceptable.
 
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Can't remember who said this. 79x100 rings a bell but I could be wrong?
Not sure if he meant the 016" valve clatter or exhaust but I think the words were "didn't sound like a Commando any more". Tried to find the reference but no luck.
 
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Keith1069 said:
Can't remember who said this. 79x100 rings a bell but I could be wrong?
Not sure if he meant the 016" valve clatter or exhaust but I think the words were "didn't sound like a Commando any more". Tried to find the reference but no luck.

No, it wasn't me mate ! (do remember reading it though) I've got a Norman White supplied PW3 in my 750 but it still sounds like a Commando to me. I rather rate the low down pulling as well. Don't ask me to go out and check it because I changed plans for it some time ago and rather got sidetracked. It was going to be a works style PR with both pipes down one side and clip-ons somewhere near the front wheel spindle but I've got too many screws in my knees now (Bottle's gone as well, I suspect :( )

I don't think that the increased clearances cause lots of tappet noise, the cam flanks are much broader than standard. The actual lift is not all that high.
 
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cash said:
I wonder if cam wear is caused by starting up on a dry sump (is wet sumping good?) ...
Cam wear is caused by starting on a dry cam :lol:
Wet sumping isn't any good and doesn't lube your cam :(

cash said:
.... and rubber covered cam chain adjusters keeping the chain quiet but allowing slack?
Rubber covered cam chain adjusters keep the chain quiete as long as they are rubber covered; afterwards, they allow for lots of slack and noise :lol:
 

L.A.B.

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brittwin said:
Wet sumping isn't any good and doesn't lube your cam

Can you be totally sure of that?

Having a large quantity of oil in the sump must result in it being thrown about inside the crankcase immediately the engine starts I would have thought?
One symptom of an overfilled sump being smoking on start-up,-so the oil is obviously being thrown against the cylinder bores, so why would this oil not help to initially lubricate the cam lobes as well?
 
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I found the message....... from Snakehips, in reply to me asking why he removed the PW3

Good question keith, I think I must like taking my commando motor apart. There were two reasons really the first may sound a bit daft but it didn't really sound like a commando anymore. Like you I have bigger ports 32mm carbs and black diamond valves and it was really blatty with the PW3 sounded good but not like a commando. Other reason I knew I would probably blow it up big time as it really breathed well and on several occasions had it well over 7,000 rpm and it kept wanting more and as it has standard crank rods cases etc I felt I was courting disaster. Still sounds sharper than your average commando with its standard cam I guess thats down to the head. Nice cam the PW3 but if you fit one you will have to open the cam tunnel out a bit to clear its big lobes and also make sure it clears the lifter tunnels ok, also check for coil bind on full lift, you will probably have to remove the heat insulators under the valve springs. Other thing that always worried me a bit was that I have 20 thou oversize exhaust valves and when the inlet and exhaust valves were on the rock passing each other you could just about get a fag paper between them (well a little bit more but not much) and I was a bit concerned they might get tangled up with each other on a missed gear. Other minor niggle is PW3 runs 11 thou clearances inlet and exhaust so does sound a little more rattley.
So those were the main reasons but I think the best solution would have been to buy another commando and have one with the PW3 etc and the other stock
Regards
Snakehips
 
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L.A.B. said:
brittwin said:
Wet sumping isn't any good and doesn't lube your cam
Can you be totally sure of that? Having a large quantity of oil in the sump must result in it being thrown about inside the crankcase immediately the engine starts I would have thought?
One symptom of an overfilled sump being smoking on start-up,-so the oil is obviously being thrown against the cylinder bores, so why would this oil not help to initially lubricate the cam lobes as well?
"Wet sumping" means that the crankshaft's big-ends & flywheel whip up the oil in the crankcase, providing a rather "random" splash pattern and "oil foam". That kind of unwanted excess "lubrication" may (more or less reliably) help to initially lube the cams at start-up, but it's negative effects are far more signiificant. If most of the oil in the tank has drained into the sump, the oil pump's scavenging side can't pump sufficient quantities of the foamy oil back into the tank, and it's pressure-feed side can't supply the engine's bearings & cylinder head appropriately - thus causing damages elsewhere.
The best way to avoid "dry cam" problems at start-up - particularly when starting the engine after some weeks in the garage - is to remove the rocker covers and to pour a tea-cup of oil into each one of the head openings. That oil can be taken from the engine's sump if it is really "wet sumping". Doing that some hours before kicking her back into life will ensure that enough oil will will have found it's way down the pushrod tunnels to the cam followers and cam lobes at start-up. That's a method you can trust - "wet sumping" isn't.
 
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