Oil tank cap - two different types at hand, which is correct?

Jdub

Jdub

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I have two different oil tank caps based on the location of the upper and lower limits of the oil measurement. One of these is either an aftermarket imposter or possibly a legitimate cap but for a different model? The picture below shows the two, matched at the same point, and the H and L locations. Does anyone have any information on this so that I prep and use the correct cap? Thank you in advance!
 

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Well it's a long standing only fill your oil level in between the high and low level on a stock oil tank so the oil don't blow out the breather so maybe the levels have changed on the second one just to get it to the right level for not overfilling the oil tank.
Just my thinking as I am not running a Commando oil tank or have a dip stick on my cap, with my 3 ltr round alloy oil tank I run 2 ltr of oil and 1 ltr air space and works for me I never do any top ups inbetween oil changes.

Ashley
 
Doesn't look like you could go wrong with either of those two level sticks....difference may be between the cross/sideways tanks vs fore/aft tanks. As long as level stays above the mesh screen at bottom and doesn't burp out the breather at all standard operating angles of the bike, you're OK.
 
Small sidetrack.

Three years ago I gave my 74 Roadster Mk11 a big birthday present. This includeed some cleaning of oil tank and repair of paint etc.

And during that time the original filler cap vanished !!!! Never been seen again over the subsequent years. Clearly taken by Martians.

I bought a new Andover one but in my head my original had oil capacity script engraved on the lid. The replacement does not.

So is my memory right or wrong? Did they have writing on the cap? Or am I confusing it with my old Matchless gone for many years?

I'm going to be 70 end of this year. 🤣🤣🤣🤣🤣. There may be more questions of this nature to come. 🤔
 
johnm said:
Small sidetrack.

Three years ago I gave my 74 Roadster Mk11 a big birthday present. This includeed some cleaning of oil tank and repair of paint etc.

And during that time the original filler cap vanished !!!! Never been seen again over the subsequent years. Clearly taken by Martians.

I bought a new Andover one but in my head my original had oil capacity script engraved on the lid. The replacement does not.

So is my memory right or wrong? Did they have writing on the cap? Or am I confusing it with my old Matchless gone for many years?

I'm going to be 70 end of this year. 🤣🤣🤣🤣🤣. There may be more questions of this nature to come. 🤔
Click to expand...
Johnny, I think you are talking about the master cylinder cap, they did have some type of mubo jumbo on there. I've never seen anything on an oil filler cap but that's just me.
 
Your right there is writing on the front brake master cylinder cap.

But no I'm definitely thinking of the oil filler.

Just wondering. Nothing to be done about it anyway I guess.
 
johnm said:
Your right there is writing on the front brake master cylinder cap.

But no I'm definitely thinking of the oil filler.

Just wondering. Nothing to be done about it anyway I guess.
Click to expand...
The oil cap on my 49 matchless g80 has that old nickel look and it has writhing around the top , I didn't look at the top of the Commando one , mine has a old 72 decal on top .
Oil tank cap - two different types at hand, which is correct?
 
Last edited:
Jdub said:
I have two different oil tank caps based on the location of the upper and lower limits of the oil measurement. One of these is either an aftermarket imposter or possibly a legitimate cap but for a different model? The picture below shows the two, matched at the same point, and the H and L locations. Does anyone have any information on this so that I prep and use the correct cap? Thank you in advance!
Click to expand...
See: https://andover-norton.co.uk/files/0c4/WEBSHOP VERSION Norton Commando Oil tank dipsticks AN.pdf
 
www.accessnorton.com

Overfilling oil tank and oil tank dipstick length

A simple question. Filled the oil tank in my Mk2A today a little to high by mistake. I think it had wet sumped a bit while it had been standing for a week. I know I should have run the engine for a while before checking the level and topping it up but for some reason forgot. Got my mind on...
www.accessnorton.com www.accessnorton.com

www.accessnorton.com

Size does matter, Oil dip stick 5"???

I remember that my 73, 850's oil tank dip stick is supposedly to short at 3 3/4" (USA inch) but I didn't find out what it should be. I seem to remember someone saying 5 (US) inches or 12.7 centimeters. Is this correct?? Thank you my learned Nortonites.
www.accessnorton.com www.accessnorton.com
 
johnm said:
Your right there is writing on the front brake master cylinder cap.

But no I'm definitely thinking of the oil filler.

Just wondering. Nothing to be done about it anyway I guess.
Click to expand...
Perhaps the engraving was some form of sacred Martian holy words, making their thievery justified?
 

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