Oil Consumption--be honest...

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?

Whitworth Ranch said:

it takes about a quart every 500 miles.

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73 750. 1100 miles of high speed work - used less than 1 pint.

Cheers

I rebuilt my 850 just over 2 years ago now, I ride it hard all the time, and have done just over 12,000 miles, I do a oil change every 2,500 miles and have never topped the oil tank between oil changes and it has been this way for over 36 years of ownership from new, weather I have a freak motor I can't say, I nomaly sit on 75 mph or above when doing highway riding and over the ton at lease once a week just to keep the motor turned :roll: but then my motor has had some high performance work done to it and I run a oil cooler as well all year round, so I must be doing something right.

Ashley

A quart every 500 miles is a lot of oil to burn. Probably more than a two stroke uses. When mine used a lot of oil it was because the valve guides were worn. Replacing them got oil consumption back to sensible levels, i.e. very little. You haven't said how many miles your bike has done.

Ian

Mine has done about 10K since I put it together - no oil consumption of note.

My oil tank cracked around the bottom mount, so I used this as an excuse to re-do it. Ended up putting new guides and black diamonds in (and repainting it in P-11 candy red), so I don't expect any problems for the foreseeable future, either.

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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As the oil grade used is not specified, doesn’t mean a thing..............

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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Something is not right. I've known people who say they can easily get from one oilchange to the next without having to add any. I'm running Redline and change it every year with 3 to 5 thousand miles. Now that I'm using one of Jim's sump breather valves and it looks like I'm good for the year. Before the valve I had mainseal incontinence into the primary.

How many miles? Has this been going on since you bought the bike? Do you have a breather valve of some kind? Done a leak down test? Maybe it's just rotted out valve guide seals, maybe it's the guides themselves. Maybe the guy you bought it from did a hone/re-ring before he put up for sale, put the rings in upside down and couldn't bear the thought of going back in to fix it. Thirty years ago a dealer in Southern California told be a story pretty much along those lines. You'll never know till you look.

Whitworth Ranch said:

Do you even care as long as it's not a quart every 15 feet?

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Not really, but that's because it's your bike. If it were my bike I'd wait for the inevitable hellish SoCal winter weather to come then pull the head and see.

Valvoline VR1 20w50. Chambers/plugs actually look pretty good. It's got a breather from Jim. There is 15K on the bike. I am certain the engine has never been apart. I was the first guy to take off the inner primary, no doubt about it. I know the second owner, who bought the bike in '75 and it has no history of engine work or even having the head off. I bought it from him around 2001, sold it, and bought it back last year with about 3K more on it. I'll have to pay closer attention to how much oil it's using. I never have compression-tested it, but it doesn't give indication of low compression. Surely, factory stem seals would be quite petrified at this point. I always have changed the oil at 1000-mile intervals and the guy I sold it to claimed this also. But I suppose he could have run it with the choke on all the time or something weird. He had no mechanical sympathy or understanding at all. Good info from folks. I have a Velo I did Nikasil, a JE piston and Total Seal rings, with an excellent valve job and modern stem seal. Might be a good excuse to go down that path here. But I think I will wait for the snow drifts and ice storms before I declare riding season over. I need to get the Velo back together, too. Can't be without running British, can I?

71 with a motor rebuilt by Ed LaBelle in Philadelphia. (Who knows when?) Comstock sump breather and Penzoil 20w50. If I fill it up to the max line it will drop to about 1/2 way between min and max and then stay there. I've never had to top off.

If you are getting 50 mpg then a quart every 500 miles is a 40:1 mix, or about what I run in my chainsaw. I am actually using about that in my 750 also. I get a pretty good blue cloud on the right side when coming off the throttle. I suspect valve seals and/or guides are due. The compression is good but I have not done a leakdown test. It might be time to make a leak down tester.

Russ

I just scored a Snap-on leakdown tester. 40:1 should keep everything lubed nicely... I've never ridden behind my bike, so I don't know what happens when I roll off. I'll be able to run it on a dyno by the end fo the month. Would be a good place to see what puffing out. I'm not overly concerned. I never let it drop the halfway and waited to see if it changed; I've always filled it when it got halfway down. I'll let it go a bit and see what happens.

My 850 leaks about 1/2 qt in 500 miles. Dunno how much it consumes otherwise.

Just wondering if you might be overfilling oil tank ,I bring mine up mid point between "L" and "F" on dip stick and that's full. How about yours?

I be I could get new stem seals on with the head in situ (he said knowing a friend had already done it that way).

I'm going to try stem seals.

For amusement I went to JS Motorports and clicked on all the stuff I like as a basis for rebuild and blew right by $2500. Go stem seals! I'll save that fancy stuff for a special.

Fresh bore, pistons and rings, head likely has 17,000 miles, no oil required between changes. 2000 mile change intervals, not down any measureable amount on the dipstick.

Craig said:

Just wondering if you might be overfilling oil tank ,I bring mine up mid point between "L" and "F" on dip stick and that's full. How about yours?

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I know Hobot has said about half way between marks for him really is full and I don't bring mine above that point and I use so little oil I can't even see it go down between changes at about 2,000 miles.

So I'd let my level get to about mid point and don't top it up and watch for a few more miles.
If it continues down sure the first guess is valves seals and if head comes off you may as well have a go through on the valves and guides.
Actually removing and reinstalling head not too difficult if you are ok with tools, for about $600 you could have a full head rebuild if necessary or just a few bucks if just scrape carbon off and new intake stem seals.

Ugh, Peel didn't hardly burn or blow out oil but my Trixie looses a pint per 500 miles or less, most out leaks in cases and barrel base and head gasket. I know better than skip an oil check and most often look in right after last shut down before any wet sump and top off so can hop on at next opportune urge to risk life and limb. The range of reports of wonderful long mileage w/o top offs and perfect heads to never leak swing arm sealed successes just make me feel unlucky or a dumb destructive mechanic. Peel never blew up like Trixie has a few times, no fault of mine, so maybe distortions in cases are harder to seal. I used fiber back up in Peel but skipped it in Trixie but will try it next time around. This brings up a side line hobby, how well I can wipe a Cdo down with just a single paper towel - when fresh hot and about to see appointments. People get a kick and uplift seeing an old bike looking good so try to do my part for Norton name. Trixie stands out parked in village square and fun to see motorcyclers swing around the gazebo to get a better look. I did get a note last year before the ring blow by found,

http://rides.webshots.com/photo/2300056 ... 1179jiXAaM

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?

Click to expand...

That's a lot of oil being burned and is about what I was burning before I rebuilt my top end with new Black Diamond valves and intake valve seals. One seal was missing and riders behind me could see puffs of smoke on downshifting, particularly on that side. So my guess would be valve seals.

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...

I guess I'll throw my 2 cents in here. I've never had to add oil to my bike's oil tank. But then it never smoked (much) except at start up maybe and has always been pretty tight in the head. I think it didn't even have oil seals on the valves originally. We won't talk about the leaks from the factory and the chain oiler.

Your oil usage sounds excessive to me.

Dave
69S