Oil Consumption--be honest...

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hobot said:
and no one would ride behind close for long either.
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RPM and chain-oiler adjustment can be a factor, if you run on the highway with a 19T front sprocket at highway speeds it is not going to help. I had someone tell me to stop riding my old beater 850 Commando in front of them on highway trips because I was covering them with oil mist. It had a lot more than 15k on it though.....
 
Wes just reported his oil use on this wkend last failed trip out 100+ miles and back to see about a cup low. His head has never been serviced since new in '71 and rings like 20,000 miles at least so smokes and smells a bit to follow. Just checked Trixie after about 300 mile top off to see about 1/4 cup down so no need to add more till a few more tanks.
 
hobot said:
I'd say if the guides were dumping a qt. per 500 miles your bike would be misfiring with oil choked plugs and no one would ride behind close for long either. Suspect oil also leaking and blowing away besides burning a good bit. This touches on a big quandary, do we just ride a new to us Cdo and fix its old age infirmities piecemeal at inopportune times or bite the big bullet and go through soup to nuts while missing a riding season or 3...
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Nope don't agree. My bike was running perfectly while burning about a pint in 200 miles. Plugs looked a little sooted on one side but otherwise not noticeable. Ran like a scalded cat.
 
Arighty tpeever, Trixie ran great a few 1000 miles last year and smoking couldn't be seen once hot, till she began to foul missfire plugs when leaving home and not yet hwy warmed. Me and Wes have been though years at a time having to clean plugs at most every stop to get going again so hope yours never evolves to that point. If plugs ain't coking up much then why worry till they do, just carry oil with ya and work up heat ranges till getting pulled over for pollution eh
 
Mine is using about a pint every 500 miles, stopped my major leaks by sealing off the chain oiler at the tank and adding the XS650 PCV valve. Still weeps a drop once in a while, but that keeps her in character. Plugs are on the dark brown side with some soot or coking not sure if its richness or oil burning, no apparent smoke from the pipes and she runs well. The clock has 31k miles and I have no idea when / if the top end was done. Oil is cheap and until she acts up i'm leaving well enough alone. Front brake upgrade is scheduled for this winters overlay.
 
Whitworth Ranch said:
Finally got into the groove with my '74 850 and have just been riding it. Not tuning, no fiddling, one-kick staring, no leaks from anything. Engine is original and I don't think the head has ever been off. Anyway, it's running great and there is no oil leaking out. I've tracked oil consumption and found it takes about a quart every 500 miles. Where does this fit in the grand scheme? What are other experiencing? Do you even care as long as it's not a quart every 15 feet?
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About a quart for 2000 miles for my bike.

I would suggest switching to Mobile 1 20-50 v-twin oil. I would bet its heavy base and resistance to heat will cut your oil consumption in half. It did for me. Jim
 
hobot said:
Arighty tpeever, Trixie ran great a few 1000 miles last year and smoking couldn't be seen once hot, till she began to foul missfire plugs when leaving home and not yet hwy warmed. Me and Wes have been though years at a time having to clean plugs at most every stop to get going again so hope yours never evolves to that point. If plugs ain't coking up much then why worry till they do, just carry oil with ya and work up heat ranges till getting pulled over for pollution eh
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If you read my earlier post you will see I solved the oil consumption issue by replacing oil seals on the intake valves. One of them was missing. Doesn't seem to burn a drop between oil changes now. Never had any plug fouling problems when I burning oil though. Have always run NGK BP7ES plugs.
 
[quote="comnoz
I would suggest switching to Mobile 1 20-50 v-twin oil. I would bet its heavy base and resistance to heat will cut your oil consumption in half. It did for me. Jim[/quote]

+1 Changed to V-twin from 25-50 Castrol with same result. About 50% less oil used
 
Nortiboy said:
[quote="comnoz
I would suggest switching to Mobile 1 20-50 v-twin oil. I would bet its heavy base and resistance to heat will cut your oil consumption in half. It did for me. Jim
Click to expand...

+1 Changed to V-twin from 25-50 Castrol with same result. About 50% less oil used[/quote]


It does seem easier to change oil than stem seals! Thanks for the tip on this. I've always tried to use one oil for all the old British cars and bikes as a matter of convenience. I will look for one of these oils and see how it goes.

Thanks also for that stem-seal-swap link. Solid info! And a diagram of the tool dimensions, too.
 
Just 250 miles into a running in period after a +20 rebore and head service (new springs,stem seals,solid rocker spacers, and lash caps) and see no huge oil consumption figures as yet, I'm running the bike on Castrol GP 50 and keep the level halfway between High and Low which seems to help with the wet sump issues that Commando's seem to suffer from.
 
Hmm spoke too soon, fouled the timing side plug today 20 km from home, oily and coked. Good thing I carry a spare... a persistent miss remains on timing side, although it could be a number of things. A look at the head has been added to the winter maintenance list... the engine is only thing I haven't had apart yet
 
>>Engine is original and I don't think the head has ever been off<<

Any idea of how any miles on motor.
If under 15K the valves and guides could be ok and you could just be looking at 38 year old rubber intake seals failing due to age.
If so just a lapping in of valves and installing new intake seals may do the trick.

Double check that the seals look good after installation.
I had a good shop do my head but then I had oil burning on one side that caused a lot of work on my part before I figured out one of the seals had split, probably upon installation.
 
rx7171 said:
>>Engine is original and I don't think the head has ever been off<<

Any idea of how any miles on motor.
If under 15K the valves and guides could be ok and you could just be looking at 38 year old rubber intake seals failing due to age.
If so just a lapping in of valves and installing new intake seals may do the trick.

Double check that the seals look good after installation.
I had a good shop do my head but then I had oil burning on one side that caused a lot of work on my part before I figured out one of the seals had split, probably upon installation.
Click to expand...

The other thing about intake valve seals to consider is that there are different aftermarket types available now. I bought my Black Diamond valves and seals from MAP in Florida. I think they advertise them as "improved" as in less likely to slide off but I can't remember exactly how they compared to the originals. They may have been ribbed like a French tickler condom where they go over the guide. They are working great for me. So spending some time looking into the different types available may be worth your time.
 
Norton in Service Release 13, around 1970 believed that a pint every 200 miles was within spec. So, you guys that are not consuming oil have performed miracles. Half a quart in 500 miles is not much over spec.


"On any machine returning an oil consumption figure heavier
than 200 miles per pint, replace the middle ring on both
pistons with the special ring 06-2262."
 
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