400EX cam chain and/or valves

[Quadman2k5]

Hell there!....i bought a used 2002 400 EX. IT runs really good, it has good compression, and is really strong. It is making a pretty loud ticking noise when running and I am thinking it is either:

a) the valves
b) the cam chain tensioner

I was wondering if those to "guesses" sound correct? I have never adjusted the valves or the cam chain tensioners...is it a difficult job?

I am going to get a video of it so you can hear the noise...maybe that will help with a diagnosis. Thanks! for any and all advice Also does anyone have a digital manual?

[Helmut]

Yeah, it could be valves, bad timing chain tensioner, or stretched timing chain. It's fairly easy to adjust the valves. The "maintenance" section of the service manual will show you how. You can't adjust the tensioner. The tensioner is spring loaded and automatically adjusts the timing chain as it wears.

You can download a service manual at the link below.

maxmekker.com

[jgar]

Adjust the valves and see if that helps. A lot of the 400ex make a distinct ticking noise. I know that must sound like a bs response. But it is something to keep in mind. DO some searching you will see. I would check out the valves and cam chain to be safe.

[Quadman2k5]

thanks guys,

im going to do the valves tomorrow and let you know my results. I will say that there is a relatively new piston and rings in it... with less than 10 hours on it. the ticking started probally 3-4 hours after the new piston was in. The ticking may or may not be related. Im thinking that if they are related that its probally the valves

[Quadman2k5]

Hey guys, Here are some videos of the running. Like I said it runs good, just his loud sound...

YouTube - IMG_0190.MOV

YouTube - 400 EX timing chain and or valves vid # 2?

In the first vid you can hear the noise lessen a little bit but then it returns

I started to do the valves but the crankshat cap it pretty stripped. I heated it up and tried loosening up but its even more stripped (basically unusable). Any suggestion on the videos and how to get the darn cap off would be helpful

[Reinox16]

new to this sight as a member but ive been watching it for awhile noiw. I had the same problem w/ my 400ex with the cover being stripped out so i could not open it up. I ended up having to use an easy-out. I used the rtiangle kind that you just hammer in and then when you spin it, it cuts even deeper but it did the job and i then had a spare on my 99 engine i put in instead.

let us know what you find out about the ticking because i also have a ticking and i think its either the head gasket has a leak and is flapping or the timing/cam chain is loose and needs a heavy duty one and maybe a tensioner too.

[jgar]

I would pull it apart and take a good look at the valves and cam chain.