Listen to my EX

[MtnEX]

Well, I finally found my brain.... LOL...

I just happened to see that sweet kick *** PINK camera I bought my wife for our anniversary.... and there big as day on the front of it is a "YouTube Capture Mode" sticker...

So guess what?... I jacked it, lol...


So anyways, now you can hear what I am trying to explain is going on with it... and see a little bit of my quad too, for visual stimulus...


When you watch the video, you can hear the tap/clack/knock sound instantly... then it just stops at about 2 seconds...anyways, here's the minutes guide to go with it...

0-2 sec = hear it
2-4 sec = gone
4-15 sec = hear it..... (8-14 sec is polluted by choppy exhaust echo)
15-17 sec = gone
17-19 sec = hear it
19 sec = gone
25 sec = hear it
Then gone until after the second rev I do.

It used to make this noise constantly until the engine got hot until I changed the engine oil type and viscosity. Now it just does it at random like that, unless I try to get it stirred back up with the throttle like I do in the video.

http://www.youtube.com/watch?v=Ep3pi9K-Fn0

It will be interesting now...................

[MtnEX]

Duh... let me try plugging the video right in here like I saw you guys did on the vid thread.

Might make it easier...

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/Ep3pi9K-Fn0&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><embed src="http://www.youtube.com/v/Ep3pi9K-Fn0&hl=en&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" width="425" height="344"></embed></object>

[geezy]

wow mine sounds just like dat and i hav an hot cam,but this just started, maybe rocker arms

[MtnEX]

Might not be the decompresser then?...


This should be interesting if nothing else.

[geezy]

yea i want this knock to stop A.S.A.P

[MtnEX]

Me too...


The wierd thing is that this noise was constant at cold startups until I changed to thinner dino oil.... makes no sense.

[geezy]

i only got 15hrs on rebuild

[MtnEX]

How far down did you go with the rebuild?

[Ruby Soho]

check around your headgasket, look in the back too where its hard to see.

the second gasket i blew it blew in the middle in the back under the carb, really hard to see

[MtnEX]

I will... I have the carb off right now as we speak...

Good time to check that and the tensioner... cause my head pipe doesn't make access easy.

[NacsMXer]

I hear it after you rev it as the revs are coming down as well.

Hear it at: 0:52 secs
sporadically at: 0:55 and 0:57 secs
1:23-1:24

Maybe it's just me, but it didn't seem like the noise went away after the 2nd rev.

I'm not exactly sure what is making the noise but I would take it apart and look inside to see whats going on. I would at least get it down to the piston/connection rod and check for abnormal play at the rod bearing and crank bearing. That will give you a chance to check out your timing chain, tensioner and timing chain guides to see if everything is functioning properly. It could be something as simple as replacing the timing chain with a CRF 450 unit, but it's hard to say if that will fix it for sure just by listening to it.

[Rip_Tear]

I'd say mine sounds very similar, but does not change upon reving up and down, it's just that constant tick. Yours seems to get louder almost like a vibration.

[MtnEX]

Head gasket area looks good.


I'm going to try checking the cam chain tensioner lifter.


NacsMXer,

Yeah I heard the same at the later times... I just didn't keep going on the time points... just did several to get everyone started.

[MtnEX]

OK... sooo...

Anyone have this noise... that has a new cam chain, etc... ?

[krt400ex]

mine ticks, but nothing like that. i have no idea what that could be. i was thinking maybe some excessive piston slap or something, but i really have no clue.

[BossHogg420]

mine makes that noise but only for a lil bit and not all the time mainly just cold start ups i've wondered my self but im not mechanically inclined enough to know whats up.....any help on this would be great!

[MtnEX]

Originally posted by BossHogg420
mine makes that noise but only for a lil bit and not all the time mainly just cold start ups i've wondered my self but im not mechanically inclined enough to know whats up.....any help on this would be great!

Very interesting... pretty much sums up exactly what mine does.

I wish I knew more too... might know more tomorrow... maybe.


My suspects were....

Something in the valvetrain... (all seems well short of a teardown)
Decompressor... (not so sure anymore)
Piston wrist pin play... (possible)
Rod bearing play... (possible)
Ring or bore wear... (possible)
Weird ignition ping... (not that, tried race gas)
The new synthetic oil... (changed to lower viscosity dino, hushed it up a lot)
Sporatic fuel delivery... (a test in progress)

Cam chain and/or tensioners/guides... (pretty sure the chain is stretched too far)

[MtnEX]

Well, I'm going around trying to UPDATE and I have now realized I'm going to pull a bunch of old threads up from the dead, and maybe even annoy some people in the process, but I feel it's worth doing...


The noise heard in that video is actually coming from the decompressor mechanism from the stock camshaft.

I have now had this professionally verified TWICE...

And after the second time around and also being in the process of carb work, I understand why.

What is happening is that... due to changing conditions.... atmospheric, and also things like fresh oil changes.... what is happening is that my engine RPM is fluctuating through a range that is getting my decompressor started clacking... That's why it comes and goes.

My carb has not been quite right since I had the work done on it, and I'm in the process of trying to correct that now.

If I can stabilize my idle, and then adjust it above this RPM range, I should never hear it again.

So nothing is wrong with my engine.... nothing is going bad or torn up.

And not only is that so... but it is obviously so.... because it has been doing it a YEAR now.