Whats leaking?

[Zakradu398]

I noticed an oil leak on my head, I lost about 1/4 quart of oil too. Any ideas whats wrong before I take it apart?

[Zakradu398]

I tried to look up the microfiche on RMATV OEM and it doesn't show anything in those spots?

[Zakradu398]

I was looking at the wrong sections, it's the rocker arm shafts from what I can see. Anyone have a walkthrough for what I need to do. I'll put in a hotcam while I'm at it and check the piston.

[jgar]

I just looked at my old rocker cover. Looks like behind the head of the bolt is a copper washer/seal. I bet yours failed. Each of the 2 bolts has 2 rocker arms on it. Should be a simple fix with the rocker cover off. Did you check to make sure both bolts are tight?

[AtvKid4Eva]

Correct^^ behind those two bolts with the allen head, you need to replace the copper washers. Ive had this happen on a buddies bike.

[AtvKid4Eva]

and your right service Honda dosent show them either. I believe they come in one of the small gasket kits Honda offers. They have a gasket kit A & B. I think we had them from a Cometic Top End Gasket kit we used to rebuild the motor.

[Zakradu398]

Originally posted by AtvKid4Eva
and your right service Honda dosent show them either. I believe they come in one of the small gasket kits Honda offers. They have a gasket kit A & B. I think we had them from a Cometic Top End Gasket kit we used to rebuild the motor.

It's on the camshaft micro. I ended up finding it.

What else Will I need when I take it apart such as gaskets and things.

While I have that off too should I might as well check the piston? and with this stuff off will a hotcam be easy to install?

[AtvKid4Eva]

id pull the valve cover off the motor to replace the gaskets. With the valve cover off you will be looking right at the stock cam and installing the Hotcam isnt much work from there. Unless the bike smokes bad, or you want to build it up id leave the piston alone. Also when you replace the crush washers that are leaking make sure you hold the valve cover upside down because when you take out those bolts the rocker arms will fall out.

[Zakradu398]

I do want an 11:1 piston but am kind of hestitant because for one, I've never opened up a 400ex motor before. Only cars/boats/chainsaws and things. and two, I'm not sure If i'll need to bore it or not. Compression was 118 like 2 months ago. I'm going to check it now and anyone have a link for a service manual, I want to print one out.,

[AtvKid4Eva]

you will need to remove the cam chain tensioner off the cylinder and then remove the cam sprocket off the stock cam. Make sure not to drop the cam chain inside the motor. You then remove the stock cam and put the hotcam in its place using the OEM bearing and cam sprocket. Makse sure the motor is at TDC by aligning the T on the flywheel through the inspection hole above your shifter. Also make sure you remove the small spring and plunger that are underneath the decompression on the stock cam as you do not need them with the hotcam. Then alight the two marking on the cam sprocket flush with the cam carrier with the third marking pointing straight up. Make sure the cam lobes are facing towards the back of the motor downwards. Im sure there are How-Tos with pics on the web. This is just a quick walkthrough.