cam chain

[below100hz]

i rebuilt my 400ex a few months ago with a 426 kit, cam and all that. it always made noises from the top end and i just figured it was valve chatter but it didnt really go away when i rebuilt it and had a complete valve job done, cut the seats, new valves all that. now its really bad and i notice its coming from the timing chain side, so im thinking its a worn timing chain? but im not really sure

i have to pull the motor apart again anyway to do heavy duty studs and replace the blown head gasket, and fix the small amount of oil that leaks out of the base gasket(is there supposed to be an o-ring on the sleeve?)

but anyhow how hard is it to get to the timing chain to change it? just have to take off the side case to get to the bottom?
and would you recommend a crf timing chain?

[Old Head]

First I'd suggest getting the manual for the bike. I would deffinatly get the heavy duty one if your gonna do it. You will have to remove the side case and remove your clutch also to get to the bottom of the chain.

[GPracer2500]

The sleeve is suppose to have an o-ring.

[cals400ex]

i used the crf chain will good success. you need to take off the right side of the case cover. you will also need to remove the flywheel. with that you will need an impact wrench or the tool honda recommends. after that i am thinking i took off the oil pump (which is only a couple bolts) in order to get to the timing chain on the bottom end.