Engine Oil Quantity

For what it is worth: '74 MK2 Commando. I have always changed/added oil by trial and error to end up half way between the H and L marks on my dipstick. This time I decided to keep track so I know how much oil to put in next time to avoid the trial and error stuff. I arrived at 88oz to end up half way between the H & L marks on the dipstick after the test ride. Note:
- I did not change the filter this time.
- I pulled the oil tank drain plug and both engine drain plugs and let it drain for a couple days on the center stand.
- My dipstick L mark is 2 7/8" from the oil cap rivet and the H mark is 2 3/8" from the oil cap rivet. I added that because I understand that there could be a few different dipsticks on these bikes. Ok, I will say it - there are a few of us dipsticks on these bikes.
- I came up with 2.3 ounces to move the oil level 1/8" on the dipstick. Therefore, if the oil gets down to the L mark, I will add approx. 4 1/2 oz oil to get back near the center between H and L.

Tom

Correct me if I’m wrong but my understanding is it’s 3 quarts including oil filter change will, once the engine has run up to temp give you your high mark. My dipstick had no mark so I etched one. Not sure of the necessity for a low mark as the temptation may be to add oil rather than run the engine in case the oil as trickled in the sump. FWIW I have done over 3k miles with 2 oil changes and never had to top up at any point. When my oil on the dipstick is close to the bottom or missing entirely I drain the sump.

According to Norman White's book, all tanks take 5 imperial pints, around 2.8 litres, and equivalent your 3 US quarts!

No mention of oil filter capacity. I figure the outcome of this is that at oil change you need to put in 5 imperial pints/3 US Quarts, or a bit less than 3 litres!

88 fluid ounces is 2.6 Litres. All of these capacities are cold oil, not the hot oil at the end of your ride!

Chuck your chosen quantity in, go for a nice ride, and a few more, check oil after each ride and top up when below the low mark. Seems good to me.

My OIF Rickman frame apparently takes 6 imperial pints, 3.4 litres (3.6 US Quarts). I also have a Commando style filter. Topping up is by sight tube like a Fastback. It takes more than 3 litres to show on the sight tube when filling after an oil change! Problem with this being that after use, once it's below the bottom of the sight tube you have no idea what is in it! But it's all a bit moot since everything over 3 litres I put in it ends up in the breather catch bottles after a regular max rpm 20 minute track session! And a bit less than 3 litres is still what a Commando oil tank holds!

I usually measure the amount I drain from the catch bottles and decide if I need to top up. Aren't we making it harder than it needs to be?

Just did my 15,000 mile service, including filter change.
2.8 litres gave 3/4 on dipstick after oil was returning.
After a ride (hot oil) it was just below "H" mark
'74 Mk2A 850

FWIW - I change the filter every time I change oil. Filters aren't expensive and these machines are worth really looking after!

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