motor oil

[bryan08crf]

right now i run 20 50 for oil i was just wondering what other people reccomend i use to run 10 40

[Rowdy Mouse Racing]

right now i run 20 50 for oil i was just wondering what other people reccomend i use to run 10 40

We run whatever the book says.. Why did you switch?

Rowdy Mouse Racing, retired grease monkey;)

[Dancrf250]

Mobil 1 15w50, i wouldnt recoment 10w40 in these engines because they run very hot. unless you in winter
10w stands for the viscosity at freezing (0c) and 40 stands for at boiling (100c) if you run a thinner oil, the hotter your engine gets with the stuff, the thinner it gets, 15w is a good 20 is what bell ray recomends, but i feel as if it is too much

[dirt4brains]

Mobil-1 0w-40 in the engine side in the Winter, then I mix 5w-30 and 20w-50 Mobil-1 oils (50/50) to make my own 10w-40 for the rest of the year. If it's wicked hot, I will run the 20w-50, but that's like only one month around these parts.

Trans side I run Mobil-1 MX4T 10w-40 all year, but sometimes Mobil-1 Synthetic ATF in the winter.

The differences in viscosity at the high temps between oils isn't as big as the difference at low temps. 10w-40 is fine for even the hottest of days.

The thicker the oil is at startup, the more wear you will get upon startup. Bearing wear, piston wear, etc. Reason: Remember, aside from use in bearinges, the oil slings around to lube things in there. The thicker it is and/or the colder the temperature is, the less the oil will want to sling and move, especially at a very cold startup with very thick oil. Always warm up your bike's engine, too, before applying a load to it, to get the clearances to operating levels.

You will notice MUCH easier startup with Mobil-1 0w-40 oil vs 20w-50 in the dead of Winter, for instance, because the thicker oil doesn't want to move, causes resistance to part movement and makes the oil pump work hard to pump it until it warms.

[matt836]

I've had Yamaha 4 strokes since 1998 and I've been using mostly 15w40 or Maxima 15w50 for the whole time. In temps over 80 or so, I sometimes will run 20w50. (I'm now a Vet A rider and have NEVER had an engine failure) I would use the recommended viscosity as per your owner's manual. You will see the recommendations overlap, and vary by temperature. Stick with the manufacturer's recommendation and you won't go wrong. Just be sure you're not using Automotive oils anywhere near your clutch...I am a factory trained european car tech, and we have 15,000 mile plus oil changes...the new long-interval synthetic oils have a lot of additives to extend oil life...like paraffin and graphite. Clutches HATE that type of lube! LOL.

Spend the money for motorcycle-specific oil. Look on the oil bottle, find the API "starburst" and you'll find the oil's rating...anything higher than "SG" is probably not your best choice. The Maxima website has some great info too!
P.S. In a pinch, I've heard Chevron diesel oil is the same as the HD-branded "screaming eagle" for wet clutches, and is a lot cheaper