What kind of oil do you use in a Honda trx250 ex?

Rotella T 15w40 I put that stuff in everything and it's cheap.

but if you want a little extra protection I would use a full synthetic 10w30

if you want to spend big bucks get the royal purple atv oil.

it's up to you, I have found that the 4 wheelers I have road wear out way before the engine does.

The key is to always change the oil and keep the oil level just right. This is way more important than anything else. Keeping clean oil in the engine is key.

Remember it doesn't have a filter so change it every 5 times you use it. It is very easy to change. So I have been using rotella 15w40 but I have some mobil 1 10w30 full synthetic on hand so I'm using that this time around.