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What Oil Should I Use? KXF250 2020
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Kawi spec is 10w-40. I run 10w-50 full syn. Stuff looks new internally after many, many hours. Changing it by 5 hours is more important than brand.
Why would you run 10w-50 if it’s spec’d 10-40
Would castrol Power 1 work?
Because it offers better protection with the only negative being cost.
Yes, Castrol is GTG. It is my conventional of choice. I run GTX 20W-50 in my 2 stroke tranny's with excellent results for the last 40 years.
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^Just a word to the wise, MxAddic: an oil with a 50W rating at operating temperature, such as 10W-50 or 20W-50 will be thicker than an oil with a 40 at the end, but that doesn't necessarily equate to a better film strength or "better protection." In fact, the flow through all the various oil journals within your engine may not be ideal with the heavier viscosity and thus your protection may be worse.
I wouldn't fix anything that isn't broken, so keep doing what you do if you've never had any problems.
I wonder how different the viscosity is between 40 and 50 at operating temp. 10w-50 pretty much forces you to use semi-synthetic and Yamaha has the only 10w-50 semi I see on RMATV. Everything else is claiming full synthetic. 10w-40 can be met with conventional oil.
Having said that I do generally side with using the rating the manufacturer specs. I have heard some people swear 10w-50 make a Kawi engine last longer though.
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