When you start pouring the oil into the crankcase of your Yamaha TTR90 motorcycle, like a mechanical Goldilocks sampling the porridge of the three bears, you don't want too much or too little. You want to pour in the amount that's just right. In an ideal world, you look in the owner's manual and find the engine oil capacity. Unfortunately, when you do so, you'll discover that the engine holds slightly more than a quart of oil, so you'll need to buy two.
The TTR90 crankcase holds 1 liter -- 1 quart, plus 1.92 oz. -- of oil. Yamaha recommends Yamalube 4 (10W-30) oil, Yamaha's proprietary blend of SAE10W-30 motor oil, or any SAE 10W-30 SE/SF type motor oil in areas where the lowest temperature is 10 degrees F, or higher. In warmer areas, where the lowest temperature is 40 degrees F or higher, you should use Yamalube 4 (20W-40) oil, or any SAE 20W-40 SE/SF type motor oil.
