400ex ???'s

[aldochina]

my buddy just got a 400ex for 500.00. I think its an 01, got the dual headlight setup. where is the vin on the frame on these? its been PC'ed, so its not readily visable. Dont know alot about them, but it looks pretty solid. everything is tight, brakes work good, got an after market carrier and axle locknut. Runs strong, but it looks like the base gasket is ripped, its leaking a bit of oil there. How much of an imidiate concern is this? he wants to just run it like that for now. This guy just bought it to ride now, and doesnt want to put any money in it. Also, it has 8" rears, but the tires are the stock tread, didnt the 400ex come with 9" rears stock? I can probably get it off him at the end of the summer for a few hundred bucks, so i dont want him to totaly smoke it on me!!lol. Got all stock plastic, one crack in front, none in the rear. I told him he did pretty good, i rarely see a running 400ex go for less than 1200.00. And even that would be cheap!! it needs a front tire, so if you have one laying around to part with. its a 22x7x10 i believe.

[MonroeMike]

From the 99-02 manual.

[bugler30]

To fix it properly you will need to take the top end apart and through a top end gasket set about it (be sure to use an OEM or OEM style head gasket), which while he is there have the cylinder honed and replaced the rings. Be sure to to be TRIPLE sure on the timing when reassembling it before cranking it over. If it isn't a horrible leak he can get away with it for the time being just keep an eye on the oil level, but fixing it properly is the best course of action. Follow the manual to the letter and you should be safe. 500 bucks is a screaming deal as it only needs about 100 bucks in parts to be 100% from what you've said. Before tear down ride it through all the gears and make sure they aren't trying to slip out, if they are that is a bit more work requiring the splitting of the case and finding and replacing the problem gears.