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Acceptable / normal oil consumption

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350Simon:
What would be considered normal for a 350/400 sohc?

I've done 500 miles of running in new pistons and rings, the bores were properly machined and honed and I know that my valve guides are on the upper end of the serviceable limit.

Oil level is just above the min mark on dipstick after 500 miles. Is this acceptable or should I really get the head reconditioned?

I'll be honest I can't detect any smoke from the exhausts in my mirrors while riding or at idle but my friend said the other day there's a faint haze when I'm giving it the beans.

Cheers
Simon

Sent from my SM-G780G using Tapatalk

Lobo:
My ex CB400F never burned oil, inc after a full rebuild. In fact no vehicle of mine burns any oil, inc a 50yo Kombi. If you’re using Max-Min quantity over a mere 500 miles there’s surely something wrong?

taysidedragon:
Try topping up the oil to the mark and see how it goes over the next 500 miles.
It might bed in and oil consumption reduce. If not, I would overhaul the valves and guides.

McCabe-Thiele (Ted):

--- Quote from: 350Simon on September 14, 2022, 11:10:37 AM ---What would be considered normal for a 350/400 sohc?

I've done 500 miles of running in new pistons and rings, the bores were properly machined and honed and I know that my valve guides are on the upper end of the serviceable limit.

Oil level is just above the min mark on dipstick after 500 miles. Is this acceptable or should I really get the head reconditioned?

I'll be honest I can't detect any smoke from the exhausts in my mirrors while riding or at idle but my friend said the other day there's a faint haze when I'm giving it the beans.

Cheers
Simon

Sent from my SM-G780G using Tapatalk

--- End quote ---

Did you replace the 4 valve stem seals?

It has been my experience that when valve stem seals need replacing on a car engine then you tend to get visible smoke if the engine stands for a while from hot  and you then restart it 5 mins later - the smoke is often just for the first 5-10 seconds then all is good. Again on cars I have found giving it the beans also burns oil & produces smoke at high engine rpm.

I would not be too concerned until you carry out your first oil & filter change then see how it goes on the next 500 miles making sure you check the oil on level ground etc.
I would also check  if there a lot of excess pressure from the crankcase vent pipe system.

kevski:
With valve guides at the upper end there was always going to be a good chance to burn oil as the valves are likely to wobble and the seals will let by.

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