Engine Noise revisited...

[MtnEX]

OK boys... remember I had that engine noise crop up last year?

Well I had it looked at and had it go away, and was reassured by mechanics and several others that it was nothing to worry about.

So I've just been riding and being observant.

Today marks the spot where I can see a certain and definate "pattern" to this which brings a brand new twist to it all...

So read what I have to say and tell me what you think...


For sure, 100% the noise is present or I should say it returns EVERY SINGLE TIME I CHANGE THE OIL.

I've even tried changing it and re-using the filter. Seems to have nothing to do with it. I could try a different brand I guess?

It has nothing to do with the oil type like I thought. It's done it with Mobil 1, Valvoline, Rotella. 20w50, 10w40, 15w40...


To someone I am sure this will make sense... I hope so anyways... Because to me it makes NONE!

I've had several people listen to it over time just for 'opinion's sake' just to see what kind of pinpointing directions I get since I can't seem to locate it for sure with a sounding rod...

The vast majority pinpoint it as coming from high in the right front of the engine.


Anyone have an explaination for this?


I'm pretty sure I know what it is coming from myself... but I have no idea why...

[tyman2395]

maybe the timing chain is strecthed causing it to slap on the adjusters

[MtnEX]

Originally posted by tyman2395
maybe the timing chain is strecthed causing it to slap on the adjusters

Well, that is what we were pretty sure was happening although it was still within the service limits...

This engine has a pretty good "freespin" turn over after a certain point in the stroke. Anyone who has ever turned it over manually in order to line up for a valve adjustment knows what I mean there...

And that action could cause a little extra slack at idle in the right RPM range... At one time I thought it was a combination of the freespin and a little extra more from the synthetic oil I changed to the first time I heard it.



But at this point, I'm pretty sure it's not the chain.

Here is why I think that (and I could be wrong)...

Right after an oil change, I can actually get on it, shift in gear, and let the clutch out enough to get a good load on it... and it will still randomly make the noise.

[MtnEX]

OK... so it's getting real late... so here is what I think...


I think it is that friggin decompression thing on the stock cam and/or the related plunger and spring.

But I have no concept of how that assembly works.


And I also don't know what in the flying sam-hell the connection is here with routine oil changes.

I mean what about the act of an oil drain would piss that thing off and get it *****in' at me???

[nakomis0]

How about the cam chain tensioner did you check that? Could be just weak and not quite broke yet.

[bigbad400]

mine does the same thing, but it doesn't disappear. it gets louder when i change the oil, right front top end, i changed my chain to the crf and mine doesn't have the decompression mechanism it has a new chain adjuster too.... leaving me to think about the guides, but i never got how them guides could make that kinda noise.


well find the bottom of this.... its going to become apparent to us real soon.... i just hope its cheap. :(