Where is All The Oil Going?

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Dan1950

Dan1950

1974 MK II Roadster
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'74 MK II, runs great, doesn't smoke but I'm going through a quart of oil every 300 miles! Does not leak a drop of engine oil. No engine oil in the primary case. Pulled the sump and perhaps a teaspoon of oil was in the sump.

When I had the carburetors off I noticed that the right cylinder had a lot of carbon built up on the head of the intake valve. The left valve head is clean, no carbon build up whatsoever. Plugs look good, no oil fouling.

No smoke at idle or when revving in neutral. I haven't been able to noticed any smoke in my mirrors while riding. There very well could be some smoke but it is not excessive.

Looking to do a valve stem seal replacement in situ.

Could that account for such excessive oil consumption?
 
Dan1950 said:
'74 MK II, runs great, doesn't smoke but I'm going through a quart of oil every 300 miles! Does not leak a drop of engine oil. No engine oil in the primary case. Pulled the sump and perhaps a teaspoon of oil was in the sump.

When I had the carburetors off I noticed that the right cylinder had a lot of carbon built up on the head of the intake valve. The left valve head is clean, no carbon build up whatsoever. Plugs look good, no oil fouling.

No smoke at idle or when revving in neutral. I haven't been able to noticed any smoke in my mirrors while riding. There very well could be some smoke but it is not excessive.

Looking to do a valve stem seal replacement in situ.

Could that account for such excessive oil consumption?
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Not sure how far you went in your rebuild but if guides and valves are new i would certainly tend to believe that you have an issue with the intake seal .. Get it running and let it idle for about 40 + seconds . Then give the throttle a twist .. If it is a bad seal you should see a pretty good puff of smoke .. I had that happen to mine on my last rebuild .
 
kommando said:
If you keep your oil level near the high mark on the dipstick then it ends up being breathed into the air filter to be burnt in engine. Fill to half way between the 2 marks.
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But that would shows signs on both intake valves .. Dan's issue is with one side only
 
It is also possible that the valve guide's press fit was lost on the right intake guide. That can cause the guide to move up and down in the head once the head warms up to temperature. Oversized [OD] valve guides are available.
 
Ron Hulton said:
Not sure how far you went in your rebuild but if guides and valves are new i would certainly tend to believe that you have an issue with the intake seal .. Get it running and let it idle for about 40 + seconds . Then give the throttle a twist .. If it is a bad seal you should see a pretty good puff of smoke .. I had that happen to mine on my last rebuild .
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Not a rebuild, just working the bugs out of a recent purchase. I did rebuild the gearbox. No smoke idling or revving.
 
A quart in 300 miles is a LOT of oil!

As has been stated, it's very difficult to see the smoke in the rear-view mirrors so have someone follow in another vehicle as you go through hard acceleration then coast down/open throttle. Acceleration smoke will show poor ring sealing. The other will show bad guides and/or seals.

NO smoke will show that someone is going out to your bike at night and removing oil from the tank! :eek:
 
Dan1950 said:
If I go that far I'm going to replace both valve stem seals. That's the plan right now.
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It`s worth taking the cover off and having a look as it could answer your question quite quickly. I have changed them in the past without stripping the motor by using the old rope trick.
 
My 850 MKII starting puffing from one side only, when blipping throttle.

Guidance was to replace intake seals which I did insitu following Ludwig's write up and tooling. Found original seals hardened and crumbling away while removing. Fitted Viton rubber (red) seals. New springs. While there I tested the oil drainage in the floor of the intake rocker box and found it slow to drain a shot of oil. Ran a long straw from an aersol spray (Seafoam can) down the drain, blew some WD40 through, chased with a length of thin wire to make it most of way down to Timing chest. Redid drainage check and much improved.

No more blip smoke.
 
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I had oily plugs and left side smoke on start up. When I checked the valve clearances, there was a pool of oil in there. I gently used a wound guitar E string to clear that drain. Sorted the problem. But, it was the left side that smoked, not the right. I'd guess from draining on the sidestand.

Next oil change showed dried Wellseal in the sump filter. I think that was what was partially blocking the drain.

Which reminds me, I need to buy two E strings, top E clears the carb's pilot circuit, bottom E for that head drain, both now in my 'Norton' tools drawer.
 
Mart UK said:
I had oily plugs and left side smoke on start up. When I checked the valve clearances, there was a pool of oil in there. I gently used a wound guitar E string to clear that drain. Sorted the problem. But, it was the left side that smoked, not the right. I'd guess from draining on the sidestand.

Next oil change showed dried Wellseal in the sump filter. I think that was what was partially blocking the drain.

Which reminds me, I need to buy two E strings, top E clears the carb's pilot circuit, bottom E for that head drain, both now in my 'Norton' tools drawer.
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And is your G string stored there too? ;)
 
Mart UK said:
I had oily plugs and left side smoke on start up. When I checked the valve clearances, there was a pool of oil in there. I gently used a wound guitar E string to clear that drain. Sorted the problem. But, it was the left side that smoked, not the right. I'd guess from draining on the sidestand.

Next oil change showed dried Wellseal in the sump filter. I think that was what was partially blocking the drain.

Which reminds me, I need to buy two E strings, top E clears the carb's pilot circuit, bottom E for that head drain, both now in my 'Norton' tools drawer.
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Here is the plug from the right cylinder. I put new plugs in and ran the bike about 35 miles on the new plugs. The old plugs looked similar albeit with a little more soot around the perimeter from running a tad rich as these do.

Where is All The Oil Going?
 
I did find the breather tube from the oil bag to the "ham can" was disconnected.
 
Dan1950 said:
I did find the breather tube from the oil bag to the "ham can" was disconnected.
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By a DPO on purpose or by accident? Some folks run these to air so as not to introduce oil vapour into intakes. I've seen a few run all the way aft, along the lip of rear mudguard and downward to spew behind bike, away from tire as much as possible.
 
Tornado said:
By a DPO on purpose or by accident? Some folks run these to air so as not to introduce oil vapour into intakes. I've seen a few run all the way aft, along the lip of rear mudguard and downward to spew behind bike, away from tire as much as possible.
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That's where mine goes.
 
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