I recently bought a 2002 Honda 400 ex. It is piped, jetted and may have a bore kit. I was wondering what is the best kind or brand and weight motor oil to use. Doing a oil change this weekend.

 

This is probably a question best answered by Reconranger.....

But where do you live? If you are in a very hot climate it might make a difference on what you should use.

I would say Amsoil 10w40 would probably work well. That is what a lot of the 400ex guys I know use. Some will use the thicker grade and some will use Honda Oil. Ask your local Honda dealer what he recommends if you cannot choose.

 

Im not sure what oil I would run in that 400 EX... If it was stock Id say Valvoline 10w-40 would be ok but maybe not the best. I have used "car type oil" in all of my Air cooled Honda and Chinese Thumpers for a while..3-5 yrs on the chinese stuff and over a couple of decades for the air cooled Honda thumpers.

Having said that....My KTM only runs on Amsoil 10wt-40 4 stroke M/C oil.

I think a air cooled, 2 valve head, 4 stroke puts much less stress on the oil, clutch, engine, etc... than a multi valved, liquid cooled 4 stroke, that is basically 1 cylinder off a indy car engine. (not actually but technologically) While Im not a scientist by any stretch of the imagination.....this has worked for me for a long time

 

I use mobil 1 MX4T 10w40 fully Sin.