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.

I don't think there's very much difference between a US inch and an Imperial inch, so 3-3/4 of either (or maybe just a little less? [Edit] 3-5/8") sounds about right.

L.A.B. wrote:I don't think there's very much difference between a US inch and an Imperial inch,

Canada and USA have always used the Imperial unit of measure since Christopher Columbus. Canada changed to metric in the 60's. I'm not sure when but the USA adapted it's own measure for liquid (probably when they discovered oil in Texas:). 1US quart = 32 oz./1 gallon = 128 oz. compared to Imperial's quart at 40 oz./1 gallon = 160 oz.

RennieK wrote:Canada and USA have always used the Imperial unit of measure since Christopher Columbus. Canada changed to metric in the 60's. I'm not sure when but the USA adapted it's own measure for liquid (probably when they discovered oil in Texas:). 1US quart = 32 oz./1 gallon = 128 oz. compared to Imperial's quart at 40 oz./1 gallon = 160 oz.

Actually, I believe the USA uses what is known as the "Customary" or "English" Unit system of measures, and although based on old English measures, are not necessarily identical to Imperial measures. http://en.wikipedia.org/wiki/United_Sta ... mary_units

The USA had of course gone its own way before the Imperial System was first introduced in Great Britain and the rest of The British Empire in 1824.
http://en.wikipedia.org/wiki/Imperial_units

Oh, I stand corrected. I should have known.

I think he wanted to know the correct length for Commandos? Here are my two, a 6"!! and the original 3-5/8" the bike came with. Hi and Low marks are different and you can just see them in the pic. Long version has Hi/Low 1.55" and 2.8" from rivet base, short is 2.1" and 3.1". So the Hi mark on the long stick is midway between the short dipstick marks. I don't know the history on these or what the short stick was used on (maybe early pre 70 tanks?) but if you have a short stick filled to the top mark tank will be overfull. At least that's what Les Emery told me and for once that makes sense.

Keith1069 wrote:I think he wanted to know the correct length for Commandos?

There were at least three different styles of Commando oil tank, the short one would be correct for the late style tank I believe?

Keith1069 wrote:So the Hi mark on the long stick is midway between the short dipstick marks.

That's not what I see in your photo?

Keith1069 wrote:if you have a short stick filled to the top mark tank will be overfull. At least that's what Les Emery told me and for once that makes sense.

Sorry, but it's not making any sense to me, as if you had a long stick, then it would be even fuller? As both the 'H' and 'L' marks on the long stick are higher.

Or is that lower mark on the long stick just a single line?

If so, why did they put the H (or Hi) mark so far away from it if it is supposed to be the maxumum oil level mark? The H marks look identical, but perhaps they are not?
I would still assume that the high mark on the long stick is where the H is?

All the Commando riders handbooks I have, specifically refer to the dipstick having 'H' and 'L' markings on them, and not a 'Hi' mark?

Long version has Hi/Low 1.55" and 2.8" from rivet base, short is 2.1" and 3.1".

From your own measurements, you also appear to have stated that the H mark on the long stick (1.55") is the 'high' mark and the other is the 'low' mark (2.8")?

I've also run my Commando with the oil level right up to the H mark on its short dipstick without any problems.
However I do expect it may be better if the oil tank was not topped right up to the H mark.

My errors, exactly as the pic. Not sure what I was thinking!!
Those marks are single lines just above the H and L stampings.

I just checked the markings on my own dipstick! And the H line is marked at 2-3/8" off the rivet, not 2.1", so perhaps this is why some owners experience problems with the short dipstick if their dipstick's H line is marked higher up at 2.1"?

Also, the L line on mine is exactly 3.0" inches off the rivet.

I have never gave the L or H lines much credence.
I fill it w/ 2 1/2 qts and forget about it.
I do check upon each start up that I have circulation.
I do not leak out the crankcase so replenishment has not been a concern.
I have the short stick which is reported marked wrong.
Marshal