It started off so simply…..

737captain · Feb 17, 2015

….but then it grew and grew and grew.

I was having a problem getting my Mk3 to run properly and it was suggested that the carbs may be in need of replacing. I bought a new set and when we removed the old ones we saw a thick black plastic like tar residue in the inlet manifolds, we assume was a result of ethanol in the fuel. Long story short I removed the head, stripped it, cleaned it and decided to reassemble using ss fasteners. I sent the head to Colorado to have the recommended studs fitted and the head tumbled. While it was there Matt noticed the exhausts had bronze inserts fitted and one was pulling out. He sent it off to have it fixed. (See the posts that were done around Christmas time). All in all they did fantastic job.

I stripped the cam followers out to properly clean an repaint the barrels and have just started to put it all back together. I am usually very careful to keep parts together and in their original position, I replaced the followers and then afterwards read that they are machined pairs and cannot be mixed. I don't think mine are but they have been moved so many times over the last few weeks it could be possible. The question is IF they got swapped what is the consequence? Is it worth dropping $400 for a new set just to be sure?

Also, the article said that the beveled side must face forward to allow proper oil distribution, mine seem to have bevels on both sides. Is this mod or later version perhaps?

Thanks in advance for you comments.

mschmitz57 · Feb 17, 2015

You can usually spot wear patterns when parts have been moving against each other. The retainers usually leave an obvious wear pattern on the follower. Look for witness marks where the retainers rub on the followers and also in the bores. Also check for wear patterns on the cam lobes and see if they match-up on the follower faces. If unsure about the matched pairs, I wouldn't loose sleep about it as long as the followers are a nice sliding fit in the bores and against each other, and there aren't any unusual wear patterns. In a perfect world you'd want to keep the matched pair together in the original bore, but they were all machined to the same dimension when new, and were probably all in a big box at the Norton assembly line. I've probably mixed-up a set at least once in my life and the world didn't come to an end.

737captain · Feb 17, 2015

Thanks Mark

Hobot · Feb 17, 2015

This happened on pre Peel as magic marker labled the plasitc bags R & L but oily handling smeared the lables so assembled cases put ink on lifters then held them against cam [sans head] a few turns to see which combo wiped the lifter most evenly. I now drop a labled note in bags or mask tape on containers. I've handled a few sets of 750 lifters and all had only the front facing edges beveled but MK3 may be toubling different there too.

mike996 · Feb 17, 2015

Well...I admit that I have no experience re mismatched followers on a Norton Commando but I have a LOT of it on car motors. I would never put a cam follower/lifter in a position that I wasn't sure it was in previously. I have seen cams destroyed in 1500 miles this way. Obviously, if you can somehow be sure the followers go back in the original location by looking at the wear markings, that's great. But if not...IN MY OPINION/experience...I would purchase new lifters/followers, unless:

IF you can check the lifter/follower mating surface (where it rides on the camshaft) with a machinist straight edge and the surface is convex all the way around, it's PROBABLY going to be fine. As lifters/followers wear, they lose the initial convex surface and become flat or even concave. This doesn't matter at all if they stay mated to the same cam lobe but it will destroy a different lobe if they are moved.

Hobot · Feb 17, 2015

so risk is lobe wiped away in a few tanks of gas Ugh. With this in mind On Trixie that did have damaged lifter faces from rod bolt pop, I sent em to comnoz to renew/true and then did the normal new cam break in over 2000 rpm and try not to go below 2000 rpm long once started and have looked in twice now over 7000 miles enjoying 2S cam Combat rpm to find them better burnished even than when newer. Send lifters off seems most mind, effort, wallet relief choice. Btw Trixie was only coasting at 50ish when siezed in its new to me era so was babying her till I got my grimy hands on her behind. I'd sure lay some organic natural fiber thread in the case seams for the longer term sealing. If was mine I'd also have the cam/lifters cyro tempered and maybe the cam nitride polished for the longest peace of mind flying away form home. Might as well send the piston rings to freeze too.

dave M · Feb 17, 2015

You can have the followers surface ground if you are worried about this. I always do ths if fitting a new cam, you generally only have to skim a small amount off.

The followers are not all the same, they are in two pairs and have a specific orientation in their bores to facilitate oil draining, you can generally see the witness marks where they have rubbed against the keeper plates.

Biscuit · Feb 17, 2015

737captain said:
….

I replaced the followers and then afterwards read that they are machined pairs and cannot be mixed. I don't think mine are but they have been moved so many times over the last few weeks it could be possible. The question is IF they got swapped what is the consequence? Is it worth dropping $400 for a new set just to be sure?

Answers have mostly been addressing any consequences of switching followers in relation to cam lobe. The statement in the manual is in regard to the followers themselves sliding against different partners and in different bores. Since the right follower is the right follower and left is left for either cylinder you have a 25% chance of getting it right on guess alone and like others have mentioned witness marks may give you a clue. When I worked on these bikes in the past, often I'd get a box o' parts with a frame. Pair the follower to each other in a manner that allows them to slide nicely with each other and you'll be good unless of course the stellite tips are obviously bad which is a whole other issue.I certainly would not spend $400 unless I had money dropping out of my a...

737captain · Feb 17, 2015

hobot said:
so risk is lobe wiped away in a few tanks of gas Ugh. With this in mind On Trixie that did have damaged lifter faces from rod bolt pop, I sent em to comnoz to renew/true and then did the normal new cam break in over 2000 rpm and try not to go below 2000 rpm long once started and have looked in twice now over 7000 miles enjoying 2S cam Combat rpm to find them better burnished even than when newer. Send lifters off seems most mind, effort, wallet relief choice. Btw Trixie was only coasting at 50ish when siezed in its new to me era so was babying her till I got my grimy hands on her behind. I'd sure lay some organic natural fiber thread in the case seams for the longer term sealing. If was mine I'd also have the cam/lifters cyro tempered and maybe the cam nitride polished for the longest peace of mind flying away form home. Might as well send the piston rings to freeze too.

What does "cryogenic tempering" do ?

Hobot · Feb 17, 2015

Generally its not the lifter in bores that bother but for sure that can so must check when two put in they slide nice enough. Of all the item to have super froozen toughed tempered cam and lifters tops my list. Cheap to have done so shipping is main cost and 'puter controlled not human skill dependent so might find shop ya can ride the item to. https://www.google.com/?gws_rd=ssl#q=be ... +tempering

I got like 3x's longer sawchains staying sharp and holding tension in 6+ hp 2 ft bar logger saw which sold me completely. Saw chains cost $6 last time I had some done a few year ago. Chains cost me ~30 bux new so like getting an 2nd one free even with shipped cost.

mschmitz57 · Feb 17, 2015

hobot said:
so assembled cases put ink on lifters then held them against cam [sans head] a few turns to see which combo wiped the lifter most evenly.

now that's an excellent idea.

mike996 · Feb 17, 2015

Well...wiping the lobe/follower most completely does not mean it's the proper match. In fact, if you do that with a new cam/lifter, you won't find a very complete "rub" at all. A complete rub could just as easily mean the lifter/follower is going to "rub" the lobe right off the cam!

dave M · Feb 17, 2015

The critical point is to keep the correct lifter face with it's respective cam lobe, this is where most wear occurs as the components are both rubbing metal to metal and under tension. If the engine has been run for a while the wear pattern between the cam and lifter becomes matched and if the lifters are swapped one or other will wear until it seats nicely again - or wears out.

The matching of the lifters to the bores of the lifter tunnels is of little consequence, unless there is a huge amount of wear within the tunnel - unusual except in high mileage examples.

Biscuit · Feb 17, 2015

dave M said:
The critical point is to keep the correct lifter face with it's respective cam lobe, this is where most wear occurs as the components are both rubbing metal to metal and under tension. If the engine has been run for a while the wear pattern between the cam and lifter becomes matched and if the lifters are swapped one or other will wear until it seats nicely again - or wears out.

The matching of the lifters to the bores of the lifter tunnels is of little consequence, unless there is a huge amount of wear within the tunnel - unusual except in high mileage examples.

I agree with this 100% but it's interesting that lifter are a "matched set" and replacements are sold like this too and in fact the only way to get replacements are in a matched set. No mention of the bores they ride in being an issue at all. I can only surmise that rights and lefts are individuals until they are lapped to each other becoming a "set".
If a set needs to be replaced you would then have a brand new stellite surface running on a cam lobe that already has a ware pattern from the original follower. Seems as though this would be only a little bit better than not worrying about where the followers were in the first place. Or maybe only half as bad.
Always something to keep one awake at night. :wink:

Hobot · Feb 17, 2015

I've replaced single lifters but lucked out they fit the bore and slid against its mate fine and still does in Trixie, [uhg wil agian once resealed]. No short cuts with a Commando for peace of mind like my leaker rebuild again. W/o rings and lifters so long the bores arn't high wear but being a Commando some are so best wishes yours is. Hm I better take my own advice to freeze Trixie cam and lifters while exposed and still in good shape along with saw chains. Didn't cryo last few and sucks how fast they get dull and loose. Might allow a few more sets of rings and a rebore to 60 over and a few more rings sets and maybe bearing before cam starts to get dull. Magical thinking of course.

acotrel · Feb 18, 2015

If the cam lobe never reaches the edge of the lifter, how does it get destroyed ? Surely a lifter rearrangement only alters the lift rate or timing slightly, even if the ramps are reversed ?

dave M · Feb 18, 2015

They are a matched pair because the two lifters in one tunnel are not the same, there is a left and a right per tunnel with a chanfer machined at one edge per lifter to facilitate the oil from the cylinder head draining out of the lifter tunnels. In a set of four lifters there are two right and two left lifters. The shiny witness marks on a used set near the bottom of the lifters where the keepers hold them in place indicates which is left and which is right and which is front and back. You can still mix them up from one tunnel to the next, but if they are surface ground this will be of no consequence.

Biscuit · Feb 18, 2015

dave M said:
They are a matched pair because the two lifters in one tunnel are not the same, there is a left and a right per tunnel with a chanfer machined at one edge per lifter to facilitate the oil from the cylinder head draining out of the lifter tunnels. In a set of four lifters there are two right and two left lifters. The shiny witness marks on a used set near the bottom of the lifters where the keepers hold them in place indicates which is left and which is right and which is front and back. You can still mix them up from one tunnel to the next, but if they are surface ground this will be of no consequence.

Respectfully, none of what you say here defines a left and a right follower, merely paired together as a "matched" set. If this was true we could just buy a left or a right to replace a damaged one and once paired with it's original mate...voila, matched set. Not so.
In an earlier post I said I thought rights and lefts were lapped together to match them. In thinking this over though I think you are right is saying they are surface ground. I think this final finishing of two selected followers was needed to ensure the correct clearance in their common bore and to each other and this is what makes them a "matched set".

dave M · Feb 18, 2015

Biscuit, they are right and left because the oil drain slot provided by the chamfers is in the front, if you fit them rotated the other way round then the drain will be in the wrong place, if you fit two of the same type there will be an oil slot at both front and rear but with half the capacity. If you look at a pair it is self evident that they are not the same, although they are symetrical. You can in practice replace a single follower - as long as it is the correct replacement in terms of it's orientation - although you have to be careful if you pick one up at random because different years or models of Norton have a deeper or shallower stop where the follower buts up against the keeper at full droop.

As long as the two sets of followers can slide nicely up and down the tunnel - they should drop down under their own weight when the barrel is inverted - without being too tght or loose then that function is taken care of. The surface grinding of the faces of an unknown or unmatched follower or followers is simply to ensure that there is less chamce of premature wear occuring between previously unmated surfaces of follower and camshaft.

Biscuit · Feb 18, 2015

Holy Smokes dave, I think we're kind of talking about the same thing,,, kind of.
I know that a set is a left, and a right. I know they are different. I know that when assembled the chamfer is toward the front. And I also feel as you do that if a set made up of a left and a right, matched or otherwise, slides up and down in the bore smoothly, it will more than likely be fine. Please re-read my posts and you will see I've been trying to say this all along.
What we are getting hung up on is, exactly what the followers are matched to. I'm convinced the new left and the new right are only matched to each other without regard to any camshaft wear patterns. While I whole heartedly agree it's good practice to label used followers so they get back to playing with their same old cam lobe pals. That is not what the book is talking about with "matched set".

It started off so simply…..

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