whats wrong with my 400?

[huntdadeer]

I ws riding my 04 400 ex about a week ago and it suddenly started making a very loud ticking noise. Something is definitly up with it, the noise is much louder the the normal valve tick i have heard on almost all 400ex's. I am thinking that it is the vavles or the timing chain. Stock exhuast, uni air filter, bored .050 over about 2 years ago (all work done by local honda shop). whats your opinions on whats wrong with it



here is a link to the quad running
http://www.youtube.com/watch?v=3B5k9qUe9Cs

[ish416]

I've had similar issues with mine sounding like that.

I had 1 bolt back out of the clutch basket and make contact with the inner case, if it is that, then you will feel the tick in the clutch lever.

The other time it was my cam chain tensioner going bad.

I would guess it's one of those issues. Start with pulling in the clutch, if all feels normal then take the tensioner out and check it to see if it is pushing out.

If it's neither of those, I would be checking the top end.

[01boneless]

its the timming chain replace it the tentioner and maybe guides and youl be good to go

[huntdadeer]

its not in the clutch sounds like top end to me, so i was leaning toward the timing chain

thanks guys planing on taking it apart tomorrow

[CJM]

Timing chain, buy one for an 02 CRF450, its stronger, better and cheaper and fits like a glove. Need to also buy a tensioner, and inspect the guides -they probably need to be replaced as well.

The one guide can be removed from the top-the other must be removed thru the clutch area b/c its bolted in there. You then need to remove the clutch, basket and such and of course need a new gasket.

[huntdadeer]

should i get new sprockets for the timing chain as well, i was reading the manual and it says to change them if you change the chain

[huntdadeer]

Took it apart today and found that the tensioner was bad. Actually it was not even putting any tension on the chain at all. So defintly getting a new one. And since I have the head and everything off, to get the guides out, I am planing on replacing the timing chain with an 02 CRF 450, the guides, which show some significant wear, and the tensioner. The question I have is about the sprockets for the timing chain. I am going to replace them as well but if i use a 450's timing chain do they need to be different than OEM, same question about the guides.

As far as aftermarket, is there a good brand to choose for the timing chain or should I go with an OEM from honda dealer?

Is there a good aftermarket tensioner? Good aftermarket guides? Or stick with OEM?

Also when I took the head off the was a stack of what seemed to be 3 metal gaskets, since a honda dealer did the .050 over and all the reassembly should I stack 3 gaskets, or is what I think is 3 is only 1, will get a picture of this tomorrow.

[CJM]

Stick with OEM for the chain, and tensioner.

You shouldnt need to replace the sprockets, highly doubt they are worn enough unless you rode around with that noise for eons.

The metal gaskets could be just a multi layered steel gasket. The best gaskets to get are made by cometic and are labeled as MLS (aka multi layered steel gasket) with a viton coating. Id buy them directly from cometic. Make SURE its the MLS ones-they make cheap fiber ones too-dont want those. And you can use the stock size, piston never comes high enough to matter unless yo got a 440 or stroker.

[hocman123]

i don't think u need to change the sprockets for the timing chain unless they look bad i have change a lot of timeing chains and never had to change the sprockets.

u need stock 400 ex guides i dont think the crf ones will fit and u can use 400 sprockets to.

i would just stick the crf timing chain they make hd chains that cost a lot but all they really are is the 450 chain in differant packageing.

they make some manual adjusting tensioners but idk anybody that has one. but i like the stock spring ones better

and the gaskit is 3 layers of metal that has 2 spots were it is rivited together to make one gasket

[dxcody]

May as well buy a enitre engine gasket set. Its like 40 or 50 bucks since you will have the right cover off, you will need the exhaust gaskets, head gasket, valve cover gasket, right crankcase gasket..

Make sure you have a low FT LBS torc wrench.

You wanna get your studs set right because if they are off it could possibly cause loss of compression, and you will end up doing it again. Also you might wanna check your valves while you have it all apart.

I think you get valve guide seals in the gasket set so you might as well replace those too. Doesnt take no time as long as you have a valves spring compressor.

Dont lose any of the Dowells either out of the right side. They might wanna fall out. lol

~Cody~

motosport.com is decent on prices for most things. I usually get stuff from them.

[huntdadeer]

Thanks guys. The input is appreciated