400ex burning oil

[crixal]

i have a friend that has a 2005 400ex. he rides the crap out of it everytime he gets on it. he changes the oil regularly. he just noticed it so he doesn't know how fast it's burning it. any ideas what it could be? he thinks it's from riding it too hard, but i have no idea.

[Honda4life05]

most likely he will need a topend rebuild. If it is burning oil, oil is getting past the rings into the combustion chamber.

[John451]

Yeah, it could be the valve seats, if its making a clacking noise it could be the cam chain tensioner is stuck and u hafta take it off and tap it with a wrench, also if its makin a clackin noise it could be the rings / piston. if its not those then the cam could be worn but problably not. or the valves are horribly dejusted

[ben_400ex]

theres usually 2 things that cause them to burn oil....
The rings are worn out, this causes blow by which is when oil gets past the piston rings and into the combustion chamber, this will cause a noticable drop in performance due to loss of compression or...
the valve stem seals are worn out, allowing oil to seep past the valves and into the combustion chamber from the top.
I'm no expert but this is jsut a couple of things that happened with mine.
hope this helps

why do 400ex smoke when you rev them high?