Outlander 400 Max Valvetrain noise

[mnviper]

I have a 2004 400 Max XT with about 3500 miles on it.
Earlier this year I noticed a fairly loud clatter from the top of the cylinder head. The noise is rpm dependent and is similar to the sound you would here from a car engine if a rocker were out of adjustment. The first time I heard this it was on start up the day after a long ride. It was about time for an oil change so I changed the oil and the sound went away. A few weeks later we took it out to some trails and put about 50 miles on it. The next morning I started it up and the noise was back. I then took the valve cover off and checked the valve clearances: intakes were both at .09 exhaust both at .14.
The chain guides look ok (at least the the parts I could see) and the tensioner seems to be at about the normal extension.
I read in other posts that the decompressor system on the 400 can be problematic so I removed the pin and the weight assembly and replaced my cam bolt with the shorter one for a 650. Once again the noise went away and I was feeling pretty good until we took it on a 20 mile ride this weekend and the noise came back the next morning. What's odd is that the noise actually "fades in" about 10 seconds after initial start-up.

I've seen a couple other posts on this board that allude to similar problems but they never really end at a clear solution.
To me this sounds like a sticking valve, but it seems like the valve clearance would be off on one valve if this were the case. Any mechanics out there have any other ideas?

[400xt]

could it be the fuel pump i thought i read on here that if your fuel is low the pump makes alot of noise. I thought i had a problem also and after i filled it up it went away.

[mnviper]

I think I ran across that thread as well. Unfortunately it doesn't seem to be related to fuel level and seems like a more substantial noise than the "tick" described for the fuel pump.

[Walrus800]

Is that what your clearances are supposed to be? It's over twice what we (500, 650, 800) need for valve gaps.

[mnviper]

According to the manual I have its
EXHAUST 0.11 to 0.19 mm
INTAKE 0.06 to 0.14 mm

You can actually feel the play in the exhaust rockers at .14. I suppose I could try taking them down closer to .11 and see if that helps.

[rkc05]

I know I have read something on here about timing chain guides I just can't find it. Send DaveB a PM he has one and may know.

[sargent-tom]

Sounds like your tensioner is sticking. The tensioner is threaded and preloaded by a wound up spring. What I believe is happening(had same issue with mine) is..when the engine is warm the tensioner has adjusted (turned on the threads) to take up all slack and all is quiet. On shut down as the engine cools the plastic tensioner shrinks(plastics suffer thermal expansion a lot more then metals )and seizes the plunger in that position. When the engine has fully cooled there now is excess slack (clearance) between the plunger and the chain guide causing noise until once again the engine has warmed. Sometimes the noise comes and goes, seemingly at will, which can be frustrating. My theory is that the threaded plunger is binding in the threaded barrel periodically causing clearance between plunger and chain guide. What I did was remove the plastic nut of the tensioner, now preload the spring 1 full turn before engaging the thread...this will give you an extra turn on the spring increasing the twist on the threaded plunger. It worked on mine, hope this works for you...

[mnviper]

Thanks Tom. That sounds promising, I'll give it a try this weekend.

[Over50]

so valve clearance is,
exhaust .0043 to .0075 inches and
intake is .0024 to .0055 inches
so you could safely set your
intake at .004 and
exhaust at .006 inches cold,
that is where I have my 04/400 set
and your manual also instructs on how to set your timing chain tension or as above from sarg

[Walrus800]

I know. I was trying tell him that he is too wide. Everybody is talking chain tensioners, but that doesn't take away the fact that the gap is STILL too wide.