Primary Oil Level

[olympus]

Happy New Year to one and all... Can i ask what is the purpose of the level plug in the primary cover, with 200cc of ATF in it as per the manual, the level comes no where near the hole..
Was the cover designed for another model or after having them cast it was decided the level was too high, leaking etc. ??

 

[kommando]

It is a level plug for the Commando, how much use it is depends on its accuracy which on a thick casting will vary. I just peep in and stop pouring oil in when the bottom of the chain touches the oil plus a bit.

 

[L.A.B.]

I use my Mk3's primary level plug and that takes approximately 370cc (of 20W/50) but causes no problems (the Mk3 primary needs a little more oil in the case due to the hydraulic tensioner in my opinion).

 

[concours]

The lower chain run being covered is my requirement...

 

[MexicoMike]

I add oil to the chain case with the level plug removed. I stop adding oil when it begins to drip from the level plug fitting. I re-install the plug when oil quits dripping from the fitting.

 

[Mart UK]

I use my Mk3's primary level plug and that takes approximately 370cc (of 20W/50) but causes no problems (the Mk3 primary needs a little more oil in the case due to the hydraulic tensioner in my opinion).

Guess this is another one of those mk3 'experience' items! The first time, I'd had to completely clean and strip the contents of the primary case, so it was dry. I just filled and waited until the level plug stopped dripping. The recent service I gave the bike, I emptied from the drain and followed the manual just adding 200cc. The manual is pretty explicit about not overfilling IIRC. From recollection, it was at the level plug, but now I'm doubting, can't remember how I checked that!

If there's one bike the level plug should be in the right place, it's the mk3, with its unique cover. I will check with the level plug and use that in future.

 

[chaztuna]

I use my Mk3's primary level plug and that takes approximately 370cc (of 20W/50) but causes no problems (the Mk3 primary needs a little more oil in the case due to the hydraulic tensioner in my opinion).

This has been discussed before. As Les points out, the Mk III chain-case holds more oil. The real issue is that you want the lower run of the primary chain covered with oil, but keep the level below the bottom of the clutch plates. It is suspected that the 200cc amount of oil for 1968 to 74 Commandos is a typo [not like there are ANY of those ] in the earlier workshop manuals. Others report that 300 cc brings the level close to the desired level on 1968 to 1974 models.

 

[concours]

 

[Mart UK]

View attachment 83907

The teeth on that last plate look well used?

 

[chaztuna]

The teeth on that last plate look well used?

Better that the teeth on the clutch plates wear, as opposed to wearing notches into the clutch center section. To my way of thinking, that is a 2nd advantage of using the Barnett clutch plates. 1st advantage is they weigh 1/3rd as much, per TimeWarp.

 

[chaztuna]

I use my Mk3's primary level plug and that takes approximately 370cc (of 20W/50) but causes no problems (the Mk3 primary needs a little more oil in the case due to the hydraulic tensioner in my opinion).

The Mk III chain-case is also wider than on earlier models, to accommodate the electric start components. That also increases the volume of oil needed.

 

[concours]

The teeth on that last plate look well used?

yup. new plate in the same image for example. Cheap as chips.

 

[chaztuna]

Guess this is another one of those mk3 'experience' items! The first time, I'd had to completely clean and strip the contents of the primary case, so it was dry. I just filled and waited until the level plug stopped dripping. The recent service I gave the bike, I emptied from the drain and followed the manual just adding 200cc. The manual is pretty explicit about not overfilling IIRC. From recollection, it was at the level plug, but now I'm doubting, can't remember how I checked that!

If there's one bike the level plug should be in the right place, it's the mk3, with its unique cover. I will check with the level plug and use that in future.

Martin, this [Section K8 for the Mk III] is one of hundreds of errors in all the manuals. It's amplified for the Mk III, due to reasons already explained above. There are MANY places where they simply copied and pasted info from the earlier workshop manuals. Section D12 & C38 are two of the worst examples. Thanks for pointing that one out. I've now corrected that in my edit.

 

[SteveA]

Way back in '75 I met Dave Rawlins, Norton works tester....

I met him at the former RAF Gaydon, then being used as a race circuit. I was having clutch slip problems with my very standard production race 1970 Fastback Commando, and he was close by, I had no idea who he was.

He told me to take out the fibre clutch plates and clean them with a bit of petrol, and he would come back. When he did, I had the cover back on, we put some standard 20w50 engine oil in but left the level plug out. He had me put a drip tray under the case and took the bike from me and leant it over until the footpeg was on the ground. I looked at him, clearly puzzled. He looked at me and said, 'the level plug is in the wrong place, it should be fine now, just do that every time'.

Never had another clutch slip problem with that bike, racing or road.

And it is still being discussed 47 years later!

 

[ashman]

7 floz is all that I use no more, I never use the level plug I use a messure cup and the chain does not have to run through the oil the vibrations and the motor moving splashes the oil onto the chain, the only time I have had slipping clutch was when new and using to recommended motor oil in the primary, with over 46 years of owning and riding my Norton I have only replace the primary chain once, I ran a belt drive for 2 years but went back to the chain so replaced the triple row chain with a new one then, I have always got long life out of my primary chain but soon will be replaced with a twin chain from Jason the chainman, I found the lighter the oil the better for you clutch and ATF F is the best its design for the old Ford transmission that had clutch plates, since using the ATF F I have never had clutch slippage or stuck clutch plates and have been using it for well over 35 years now and my Norton was a everyday rider till about 7 years now, but I still ride it regularly.
The worst thing you can do is to over fill your primary as well your gearbox, never had gearbox oil in my primary as I don't over fill it.

Ashley

 

[concours]

Way back in '75 I met Dave Rawlins, Norton works tester....

I met him at the former RAF Gaydon, then being used as a race circuit. I was having clutch slip problems with my very standard production race 1970 Fastback Commando, and he was close by, I had no idea who he was.

He told me to take out the fibre clutch plates and clean them with a bit of petrol, and he would come back. When he did, I had the cover back on, we put some standard 20w50 engine oil in but left the level plug out. He had me put a drip tray under the case and took the bike from me and leant it over until the footpeg was on the ground. I looked at him, clearly puzzled. He looked at me and said, 'the level plug is in the wrong place, it should be fine now, just do that every time'.

Never had another clutch slip problem with that bike, racing or road.

And it is still being discussed 47 years later!

I continue to offer that starving the chain, sprockets, clutch basket bearing of proper lubrication is not the correct answer to remedy the malfunctioning clutch.
The answer lies here: https://atlanticgreen.com/ndnsclutch.htm
Perfect no slip, no grab, progressive smooth clutch the first time.

 

[robs ss]

I continue to offer that starving the chain, sprockets, clutch basket bearing of proper lubrication is not the correct answer to remedy the malfunctioning clutch.
The answer lies here: https://atlanticgreen.com/ndnsclutch.htm
Perfect no slip, no grab, progressive smooth clutch the first time.

I must be blind!
Where on that page does it mention anything about oil level in the primary? (topic of thread)

 

[Time Warp]

Happy New Year to one and all... Can i ask what is the purpose of the level plug in the primary cover, with 200cc of ATF in it as per the manual, the level comes no where near the hole..
Was the cover designed for another model or after having them cast it was decided the level was too high, leaking etc. ??

I think the factory was making things up on a daily basis which could change the next day or shift.

Even if filled to the lower level of the plug hole it is still below the lower chain run.
How much oil does it need, enough for the lower chain run at the larger diameter (clutch drum) to pick it up sparingly (perhaps)
That could be sight guessimated when the clutch pack height is attended to.

 

[Mart UK]

I must be blind!
Where on that page does it mention anything about oil level in the primary? (topic of thread)

With respect and don't want to offend, I thought it was on topic. It does say: "Overfilling the primary is sometimes a contributing factor to a slipping/dragging clutch." I found it interesting, in response to the earlier comment from Ashman, which introduced clutch slip.

There's been a bit of policing 'off-topic' lately. Fair enough in some cases. But, we're having a conversation around the topic here and sharing experience, which I'm finding helpful. Keen to learn from the forum.

 

[marinatlas]

Way back in '75 I met Dave Rawlins, Norton works tester....

I met him at the former RAF Gaydon, then being used as a race circuit. I was having clutch slip problems with my very standard production race 1970 Fastback Commando, and he was close by, I had no idea who he was.

He told me to take out the fibre clutch plates and clean them with a bit of petrol, and he would come back. When he did, I had the cover back on, we put some standard 20w50 engine oil in but left the level plug out. He had me put a drip tray under the case and took the bike from me and leant it over until the footpeg was on the ground. I looked at him, clearly puzzled. He looked at me and said, 'the level plug is in the wrong place, it should be fine now, just do that every time'.

Never had another clutch slip problem with that bike, racing or road.

And it is still being discussed 47 years later!

Yes Steve , in the french manual it is said to lean the bike till the side stand nearly touch the ground ........