Crankcase Breather

[shaunstaples]

It looks worse I think because of scale needed, I have a 200 psi gauge so 10psi is about twice thickness of needle. When its cold I think I can see pressure relief valve working, it gets to a point and then doesn't increase anymore with rev's.
As I've seen it relief working, I'll probably try some SAE 50 ( Different brand ) and compare. I replaced all the filters to get a good base to work from
I want to ride it this summer, so using a gauge at first was a must for me. No noise on light load, that's first thing I listen for and it felt smoother than I anticipated, even with the sewing machine oil! So some decent 50 for this fair weather whittler is a must!

There seems to be a tendency to rebore, where a re-ring will often get similar results. I've been helping my son with his MX5 import and his engine has over 250km on it and using a lot of oil. He was insisting to get it rebored but the bores felt ok to me, and the oil control rings were well and truly gummed in. He took it to a motor engineering shop who agreed to measure it for him and report. They honed the bores and supplied rings and shells. Same oil pump and motor is now great and doesn't use any oil. Left to him it would have been rebored, new oil pump etc. Better and last longer yes, but comparable result, just cost a lot more?

[clive]

Very Disappointed with oil, its supposed to be straight 40, ....... Not sure if I can mention brand but I'll use it in the oil can, not even in the mower!

Well here goes

worms.jpg

I would not be using straight 40 as it is straight 50 that is recommended at this time of year. Many of us use 20/50 as it reduces the oil pressure (and the risk of leaks) at start up and should give a slightly higher pressure when hot. Like Groily I cannot comment on the pressures you quote as I have never checked them on any of my bikes.

[shaunstaples]

I went with sae 40 for fear of cold oil pressure and what the previous owner recommended, I couldn’t go blind so had to see the pressure as I’d be “having kittens”!
I do feel more confident now I can see the relief pressure on the gauge. Can’t go 20/50 yet as I’ve not seen how dirty insides are yet.
I was comparing the data on most of the brands this morning that can be bothered to publish it and 20/50 seems to sit somewhere between 40 and 50 generally below the halfway point.
I had a bmw 650 single and the gearbox was clunky, worse when hot so tried 10/60 think it was what Subaru boxer uses and had better results than any of the recommended 4t I tried.
I know it is a can of worms don’t want to open that, but this is thin and it wasn’t that warm, definitely wouldn’t say hot!
I think this oil is well under par,,,,,, straight 50 it is then