Commando oil consumption

How much oil should a healthy Commando engine consume under normal service? (Leaks not withstanding.) I'd post a poll, but I dunno what range of numbers to list.

I checked my 850 in 2019. At that time it was not leaking any appreciable amount. Oil consumption was about 1US quart in 2000 miles. That was fairly vigorous mountain riding.

Glen

MK3 850 doesn't leak oil, and over the last 1200 miles it used next to nothing.
Dave

I believe I should track mine, but as little as it goes anymore than 20-40 miles per ride its rather difficult because there's not much time at full operating temperature. Even with that I can say its not very much... Perhaps a tad over 1/2 quart US. The accuracy is not tracked because of regular checking with a quick top off prior to being put away.
Lets say around 1/2 qt. between changes which are done around every 1500 miles, or seemingly forever with my riding habits..... Whew! What a long winded statement giving little real info.

jbruney said:

I believe I should track mine, but as little as it goes anymore than 20-40 miles per ride its rather difficult because there's not much time at full operating temperature. Even with that I can say its not very much... Perhaps a tad over 1/2 quart US. The accuracy is not tracked because of regular checking with a quick top off prior to being put away.
Lets say around 1/2 qt. between changes which are done around every 1500 miles, or seemingly forever with my riding habits..... Whew! What a long winded statement giving little real info.

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I'd guess I'm in a similar boat (!!)
Bike gets used sporadically, sometimes short trips, sometimes longer...
But, tank gets filled to marker at each oil change, then the tin sits undisturbed 'til the next one

Seems like just skirting around with one not getting up to and maintaining the operating temp isn't really a good thing to do, and would increase oil consumption.... I just cannot ride more than I do on it, so I'll admit my accounting isn't worth a hill of beans.... Oil use/consumption hasn't reached the point to be more than a minor nuisance is a much more accurate description.
This forced me into starting/ running, checking/topping after becoming curious/stimulated out of lethargy by this great query.... Now I'll have to go for another improper ride since the motor is warm and oil topped..... topped fuel 2 days past after last ride.******* I'm finished prattling, so now all may ride also.

A poll now please because I've used too much ink and paper.

I change oil every 1000 miles, and do not need to top up or see any noticeable drop in level.

maylar said:

How much oil should a healthy Commando engine consume under normal service? (Leaks not withstanding.) I'd post a poll, but I dunno what range of numbers to list.

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300 ml per 1000 miles , air temperature average 25 celsius, up to 450 ml per 1000 mles air temperature average 38 celsius, andover norton parts (gandini pistons, cast iron valve guides, standard valves), 80,000 gentle touring miles on engine, high carbon build up in combustion chambers and piston crowns, engine oil is penrite 40/70 W multigrade mineral, changed every 3000 miles. I don,t know if the motor is healthy.

justin scroope said:

I don't know if the motor is healthy.

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In terms of oil consumption, I would consider an engine that doesn't smoke as being healthy. Smoking at idle or decel would be valve seals, smoking under load would be rings.

I ride my bike a lot, so oil & filter changes are about every 2000 miles. I have an oil pressure gauge, and keep a close eye on it. I run Castrol GTX 20w50. I also run Lucas oil treatment in my engine (& transmission for that matter).

Depending on how spirited of a ride I go on, it might use a litre between oil changes. I don't really keep track as I do not see this as excessive.

This last change, I upped the Lucas to a full litre, and it has not used hardly any in the last 1000 miles. The hot oil pressure at idle is improved as well - not that I spend a lot of time idling...

Hi All,
In my opinion, if your motor is running well without obvious smoking, a small amount of oil consumption is not a problem.
Very good oil control that we take for granted these days was probably not a major priority when Commandos were built.
As it is an (rather primitive) air cooled engine it will probably always use some oil. Internal combustion aero engines drink oil at an alarming rate even when in good condition.
Of course much depends on the use the bike is put to. Often small amounts of oil consumption can be masked by contamination from products of combustion if the oil is too cool (short runs) only to show up when these are evaporated off on a long fast run.
How much is acceptable, I guess it’s a personal thing but anything less than 500 ml per 1000 miles wouldn’t overly concerned me (sorry for the mixing of units).
One thing is for sure, even the most visually hideous oil leak does not contribute very much to oil consumption. In other words, a little oil goes a long way.
al