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Old 01-22-2013, 09:03 AM   #16
Steve G.
Beastly Adventurer
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Joined: Oct 2004
Location: West is the Best
Oddometer: 7,114
Originally Posted by TINK View Post
Now for something completely different...

What about Castrol 4T, anyone using this? It's an old school mineral base SG oil.


It's really quite simple. API spec SG, 20w-50. It's an air cooled engine, with it's much larger clearances at piston/cylinder compared to liquid cooled engines so 20w is better than 15w. ZDDP is exceedingly important, so some research may be needed for this as even some 'bike' oils are now using reduced ZDDP additive.
As much as I'm a strong proponent of FULL synthetic oils, I think that extending oil changes because it's synthetic is misguided. Synthetics don't break down near as fast as non-synthetics, but, they get contaminated just as fast with acidic byproducts of combustion sneaking past the bigger clearances of an air cooled piston rings. Changing the oil more often using less expensive non-synthetic oil is by far a better way to go.
If only there was available a 20w-50 diesel spec oil [api spec CC -CD], which has very high ZDDP, but most all are 15w-40, too thin for an airhead on a hot summer day.
BTW, I use Castrol 20w-50 bike oil, api spec SG.
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