SOHC.co.uk Forums > CB500/550
Oil !!!!
taysidedragon:
--- Quote from: Bryanj on November 01, 2024, 02:56:56 PM ---As long as it does not have "friction modifiers" listed as in it should be fine, look at the SE rating in your handbook and on the can
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What Bryan says. 👍 It's the friction modifiers in car oil that cause clutch slip in our wet clutch bikes.
deltarider:
If you don't ride at subzero temperatures, a 15W-40 is the better choice. Mineral or semi-synthetic are both OK. http://forums.sohc4.net/index.php/topic,186850.msg2168655.html#msg2168655
McCabe-Thiele (Ted):
--- Quote from: Murf on November 01, 2024, 10:59:00 AM ---
A problem with a part synthetic oil could be bore glazing on a lightly used classic bike engine, I see a simple answer to that, Don’t Ride like a Pussy, they like a bit of a thrash😄
I know this answer isnt SOHC specific but I think the same thing with engine oil apply to most classic Hondas.
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I really can't see any reason how a part synthetic oil or fully synthetic oil would have any bearing on bore glazing.
The synthetic base oil is stable for much longer periods of time in an engine. They do this by making the base oil from scratch rather than refining crude oil. A lot of it is to do with the molecular structure of the oil itself, you have more linear molecules that are chemically the same as branch chain molecules. As crude oil has it's origins from plants (organic) there are a wide variety of oil structures within the oil - more branch chain than linear. With synthetic oil you manufacture the base oil using a stronger molecule that takes longer to loose it's essential properties as they use a stronger molecular structure as a starting point.
Back in the 1960's ICI manufactured semi-synthetic petrol as a by-product of the chemical industries they had in the UK including the by-products from Town Gas & making smokeless coal before we converted to North Sea Gas in around 1971 ish.
A gallon of ICI synthetic petrol was heavier than normal petrol due to having much fewer branch chain molecules so it was more dense. As a bonus it was also marginally better as a return on mpg. Once we had switched to North Sea Gas it was no longer economical to manufacture synthetic petrol. I have tried to simplfy the difference but there is an optimum length of carbon molecules involved. https://www.chemistryworld.com/features/is-synthetic-petroleum-the-missing-link-in-the-route-to-net-zero/4015785.article
I'm not sure if a gallon of synthetic oils is heavier than a gallon of mineral oil - I suspect it might be marginally denser.
When Mobil1 was being developed they had a problem with the sulphur build up in engine oils over a certain mileage due to acid build up - the solution was to add micronised chalk to neutralise the acid.
Aside from the base oil starting point most mineral & synthetic oils contain very similar additatives when they reach the oil can.
Update - Diesel oil contains a lot more detergent to keep the carbon in suspension - hence why Shell Rotella turns jet black within a few miles after an oil change.
Bryanj:
All i can add to the synthetic/mineral debate is the V6/8 Merc commercial diesels after rebuild are run in on mineral oil and dont tend to leak or burn oil, after service they swap to long life synthetic and guess what, they leak and burn oil!
McCabe-Thiele (Ted):
--- Quote from: Bryanj on November 01, 2024, 04:43:23 PM ---All i can add to the synthetic/mineral debate is the V6/8 Merc commercial diesels after rebuild are run in on mineral oil and dont tend to leak or burn oil, after service they swap to long life synthetic and guess what, they leak and burn oil!
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True Bryan, fully Synthetic oil is very searching, plus being so thin on a worn engne you will burn oil.
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