MKIII Primary chain noise

Had him leave the clean up (drilling/sanding/polishing,etc.) for me to complete. Exactly what I asked for.

CR125Honda said:

Update time..

No spring behind the ball.

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Is there an echo in here?

What I am not hearing is posters who were wrong apologising, and conceding they were, in fact, wrong. But apparently the good news is some of them at least are going to teach others, even though they clearly have no correct knowledge on the matter. What lucky ones who get to hear that.

Their ego is such that they would rather others were deceived than admit their error. True enthusiasts.

Of course, I am not even close to surprised.

As a Newbie here, I really don't want to do this... but I'll try..
Seems to me there has been a failure to communicate (Strother Martin)
You two both obviously have great mechanical know how.
I think it's nomenclature that's throwing a wrench in the works.

10,000 hour Corporate pilot with an A&P here.
The Gulfstream I flew had check valves and shuttle valves.

In general...
Check valves ~ spring load regulates pressure
Shuttle Valve ~ Pressure, or lack there of, regulates position of valve

As I see it..
This system is a pseudo combination of the two.
Assume new, oil primed assembly - oil reservoir (plate to tensioner body) full, chambers in top and bottom tensioners full.
Springs keep the top and bottom tensioners pressed against the chain. Think check valve only spring is in another component. This keeps the ball seated until the chain stretches and allows the tensioners to expand.
The negative pressure as the tensioners expand (Think shuttle valve) moves the ball open, allowing oil to fill the tensioner chambers.
Any bleeding, age, wear also need to be accounted for.
My thought is that the small hole in the tensioner halves keep the shafts lubricated as they move up and down (in somewhat "unison" due to the thru hole in the body) .
Could there be a minute' ball movement with each power pulse on the engine or change in throttle? Certainly possible. Oil viscosity make a difference? Any more variables? Do I care? It works! Could be way off but there's my two cents.

I'm sure Bernoulli, Newton and Einstein would like to get involved here.... but they can't. I'm smarter anyway. Believe me. Take my word for it.. Not

Diplomatic enough? Easier to play nice. Everyone here wants the same thing.
Really don't want to quote Rodney King..

Did I mention I've had the same Triumph 650 for 41 years and CT70 for 46!

Life's a Journey, Enjoy the travel.

Ken

CR125Honda said:

I think it's nomenclature that's throwing a wrench in the works.

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The norton, agreed, does not have a "spring" check valve.https://www.youtube.com/watch?v=Sj1vJkhc5XE&app=desktop
Is a "shuttle" valve the same as a "swing" check valve per above video? (obliviously yes?)
It seems to be all about specific terminology rather than function.
The flow function and time response of the system components are key.
I prefer to focus on the function and speed of hydraulic response rather than selection of a specific name like swing check valve.

dynodave said:

It seems to be all about specific terminology rather than function.

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No, it has absolutely nothing at all to do with terminology, but rather it is all about the function. You mistakenly thought that the valve is a "one way check valve", intended to only allow oil into the plungers, and not out. That is incorrect. When either of the plungers is compressed, the force that is initiated against the other plunger is initially reduced by the exit flow of oil back out of the shuttle valve. The ball is not held by a spring, so anytime oil is drawn into the plungers, the ball has moved inwards and remains there until flow causes it to move back out, at which point exit flow ceases. This is essential to avoid over-tensioning of the chain, particularly in respect of any loose spots in the chain which would cause oil to be drawn in, and any tight spots would subsequently be over-tensioned. That does not occur of course, as the valve is designed specifically to be "two-way" to address such a dynamic.

Cover cleaned up nicely..

CR125Honda said:

Cover cleaned up nicely..

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nice job!

Weird “crack” in the cage on the starter sprag. Can someone confirm this is toast before I order a new one? It’s the original 14 T. Understand the new ones are 18 T.
Ken

Mine came to me that way new. Why is a mystery.

Very strange. The edges (where it’s separated) look smooth, like it was made that way. Had to post the pic and question to find out if this is ok. Starter worked fine prior to disassembly. Suppose I’ll reinstall unless there’s a good reason to buy the new version.

CR125Honda said:

The edges (where it’s separated) look smooth, like it was made that way.

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It is normal, but it must weaken the cage.

Later sprags have a separate sheet metal clip (or clips) attached to the outer cage instead of the cuts and can be seen at the 6 o'clock position in the image below.

Thanks,
Happy to get confirmation this is normal.
The starter had operated normally prior to disassembly.
Got in to this because of a noise coming from the primary.
After seeing what I thought was an "abnormality" on the cage, I wanted to be sure it couldn't be part of the noise issue.
Ken

CR125Honda said:

Very strange. The edges (where it’s separated) look smooth, like it was made that way. Had to post the pic and question to find out if this is ok. Starter worked fine prior to disassembly. Suppose I’ll reinstall unless there’s a good reason to buy the new version.

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Mine was the same and like you I was unsure if it was a crack or as per the manufactured item. I replaced it for the 18 sprag version in any event as was claimed to be a stronger unit and the sprag seemed to be notoriously temperamental. I was struggling with some starter/anti-backfire issues so I just went for and it seems to work OK.

Just watch out though as the Andover Norton web site notes that the drive gear and the engine sprocket need to be 06-4731 and 06-4681 respectively if you go with the 18 sprag they're supplying (06-4733). I only became aware of this after I had bought and installed mine, seems to be Ok but it hasn't backfired yet, so who knows.

Balmain Bill said:

Mine was the same and like you I was unsure if it was a crack or as per the manufactured item. I replaced it for the 18 sprag version in any event as was claimed to be a stronger unit and the sprag seemed to be notoriously temperamental. I was struggling with some starter/anti-backfire issues so I just went for and it seems to work OK.

Just watch out though as the Andover Norton web site notes that the drive gear and the engine sprocket need to be 06-4731 and 06-4681 respectively if you go with the 18 sprag they're supplying (06-4733). I only became aware of this after I had bought and installed mine, seems to be Ok but it hasn't backfired yet, so who knows.

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Thanks for that heads up. Good info.
After confirmation the 14T wasn’t damaged, I decided to re-install it.
Starter was working fine before. hopefully, that will continue.

New primary chain installed.



Tensioner is working great. Primed prior to installation. Reservoir is holding oil.

For info https://www.accessnorton.com/NortonCommando/dc-4127-sprag-from-aliexpress.27655/

CR125Honda said:

New primary chain installed.

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The stator is installed the wrong way round. The wire must exit outwards, and then loop inwards. There is inadequate room for the wire installed as it is.

Thanks for looking out CCR. That has me concerned.
Here’s a pic taken just before disassembly the other day.
Just assumed it was installed correctly so that’s how I re-installed it.
The chain had excess slack and the tensioner’s weren’t working.
Would assume the chain would have rubbed the statorwire back then if it was going to be an issue?
Now it has a new chain and working tensioner’s.

Just pushed up on the chain. Closest point leaves about 1/4” gap. At rest the gap is appx. 1/2”.

Yea, I know. I’m trying to talk myself into not redoing this.

CR125Honda said:

Just pushed up on the chain. Closest point leaves about 1/4” gap. At rest the gap is appx. 1/2”.

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The chain can not reach the cable, as the tensioners cannot travel that far.

But that is not the issue. The cable must exit outwards to avoid being trapped between the stator body and the mounting bracket.

You have the inner side of the stator facing out. The side with the cable exiting faces out.

You should be able to just draw the cable through somewhat, and flip the stator.

Are the washers behind those stator nuts? I cannot tell from the pic if they are the correct "7/16 af" type.

Classic Cycle Repair said:

The chain can not reach the cable, as the tensioners cannot travel that far.

But that is not the issue. The cable must exit outwards to avoid being trapped between the stator body and the mounting bracket.

You have the inner side of the stator facing out. The side with the cable exiting faces out.

You should be able to just draw the cable through somewhat, and flip the stator.

Are the washers behind those stator nuts? I cannot tell from the pic if they are the correct "7/16 af" type.

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Thanks CCR,
Will take a look at that. Would think I’d have noticed if the wire was getting pinched while tightening the stator. Need to order some washers, there weren’t any there. Taking a lil time off but I’ll flip it around when I get back at this.
Ken