Another engine noise thread! With video!

Of course there's more to it than just posting a video and getting feedback but, the community is great here and I'd love to hear some opinions.  Doing a big trip NEXT weekend and wondering if I should source another ride or it's a simpler fix like a cam chain, ACCT, etc.  To me, it sounds lighter and higher than a rod would sound (trying to compare with other vids) and seems to be louder on the right side (ACCT side).
 
-18k miles.  Can't remember when exactly but, replaced the rings and wristpin on the piston a few years back.  Otherwise, the engine/tranny/clutch is stock.
-Yep, it's got an ACCT!
 
Anyway, check it out...
http://youtu.be/koDuqRE2PWU

Sounds like hydraulic lifters tapping on a v8. When was the last time you checked your valve lash?

Sounds like hydraulic lifters tapping on a v8. When was the last time you checked your valve lash?

At least 5,000 mi ago.

Sounds like hydraulic lifters tapping on a v8. When was the last time you checked your valve lash?

 

Yeah, except in this case (non-hydraulic flat tappets) "noisy" is good, means you got clearance... when it gets quiet then it's a problem.  The tapping sound is pretty high-pitched, maybe I would check that the header bolts are tight and there are no exhaust leaks.  Then proceed to remove the valve cover and check valve clearances, timing chain tension, ACCT unit, inspect the decomp mechanism (search for exactly what to check).

Possible Auto Decomp issue

Finally found my feeler gauges!  Still need to check specs (crazy around here).  Should I kill the auto decomp while I'm in here?  I know it will be harder to start but, will I regret removing it?

Ah, gotcha. Perhaps an inaccurate comparison but it sort of sounded like valvetrain noise to my ears.

thats the cam chain

Fools. Either he needs a new cam chain ( how many miles motor done) and but a mcct. The acct is crap

Fools. Either he needs a new cam chain ( how many miles motor done) and but a mcct. The acct is crap

18 thousand miles on the stock cam chain.  From what I can tell, both the ACCT and the Auto Decomp seem to be working just fine by hand.  Valves are all within spec with the exception of the Left Exhaust, it's a pinch on the tight side, but barely.  So, it isn't them.  If my ACCT seems to work, why is the ACCT crap?  I know an MCCT is preferred BUT, I need to find the source of this noise.

 

Here's a hypothetical:  Let's say the ACCT is working PERFECTLY.  Can a worn cam chain make that noise with a good ACCT?  If it seems to be working fine (ratchet works, spring works), what could it be doing that isn't fine?  Dig?

Edited by DJCDRZ

My guess is also ACCT just cuz thats what it sounded like when I installed/ adjusted mine.

Edited by Mojocava

Well, if it is a cam chain and or tensioner, it's gonna have to wait. I have a 500 mile desert ride in 7 days. There's no way I can get a MCCT and a chain AND install them AND be ready to go in a week. Gonna have to borrow a bike. Damn, I love my baby...

Edited by DJCDRZ

If you cam chain is streched it will be shaking around making this noise the acct only goes out so far . For. £30 buy a mcct trust me also buy a cam chain while your at it order a klx 400 one they are cheaper

Thanks. If the cam chain was easier to install, I'd push and get it done this week. Too much work. Would it be dumb to get a MCCT and tighten her up and do the chain later?

Thanks. If the cam chain was easier to install, I'd push and get it done this week. Too much work. Would it be dumb to get a MCCT and tighten her up and do the chain later?

yeah get a mcct and see if it gets better mine makes this noise , new cam chain 3000 miles ago with mcct still makes the noise not as bad as yours though it seems worse at tick over . The cam chain isnt that hard to install aslong as you have a air compressor ;) but like everyone says loud exhaust pipes help ahahha

Got a MCCT installed and the noise is gone!  Woo!  I don't feel that the ACCT failed me by any means but, after 18K, the combination of a weaker spring on the ACCT and a worn chain allowed more slap than desired.

Got a MCCT installed and the noise is gone! Woo! I don't feel that the ACCT failed me by any means but, after 18K, the combination of a weaker spring on the ACCT and a worn chain allowed more slap than desired.

nice one buddy!

Got a MCCT installed and the noise is gone!  Woo!  I don't feel that the ACCT failed me by any means but, after 18K, the combination of a weaker spring on the ACCT and a worn chain allowed more slap than desired.

 

 

it's not a weaker spring, it's a TOO STRONG spring. it stretches the timing chain. i'll expect you to need to adjust your MCCT pretty often now, like every 100-300 miles. 

 

if this is the case (i'm expecting so with 18K miles on it), go ahead and order the klx400 chain, a clutch SIDE (not clutch cover) gasket, and read up on how to remove the auto-decomp mechanism. the auto-decomp will be the next thing to start sounding terrible, as it will rotate on the cam, and slam back/forth against it's dowel pin. might as well cut it off while you have the cams out for the timing chain install. 

 

dont forget to be very gentle with the cam cap screws, and the valve cover screws. they don't need much, and WILL STRIP or break if over torqued. ;-)

 

 

enjoy the ride :D 

 

Here's a hypothetical:  Let's say the ACCT is working PERFECTLY.  Can a worn cam chain make that noise with a good ACCT?  If it seems to be working fine (ratchet works, spring works), what could it be doing that isn't fine?  Dig?

Only if the chain is worn to the point the ACCT is fully extended.

 

Remove valve cover, remove the top chain guide.. IS the chain tight between the sprockets? if taut...  then  your ACT is working as designed.

 

 You can also set the cams to TDC compression stroke, remove the ACT spring cap and spring from the back, then the ACT from the motor and see if it is fully extended. 

 

 

 EDIT, noticed you "fixed" the noise with a MCCT... .. in my experiences your fix will be short lived.. if the chain was slapping and noisy with an ACT.. the chain is worn out.. if it is very quite with the MCCT... your likely too tight.. and in any case the chain is going to wear in short order and you'll try and tighten the MCCT some more.. 

It's a self licking ice cream cone.. the more you tighten, the more it'll wear. 

Only if the chain is worn to the point the ACCT is fully extended.

 

Remove valve cover, remove the top chain guide.. IS the chain tight between the sprockets? if taut...  then  your ACT is working as designed.

 

 You can also set the cams to TDC compression stroke, remove the ACT spring cap and spring from the back, then the ACT from the motor and see if it is fully extended. 

 

 

 EDIT, noticed you "fixed" the noise with a MCCT... .. in my experiences your fix will be short lived.. if the chain was slapping and noisy with an ACT.. the chain is worn out.. if it is very quite with the MCCT... your likely too tight.. and in any case the chain is going to wear in short order and you'll try and tighten the MCCT some more.. 

It's a self licking ice cream cone.. the more you tighten, the more it'll wear. 

The chain was taut between the cams with the ACCT.

 

I understand how the chain will continue to stretch at this point.  My goal is to get 500 more miles (tops) out of my current setup.  I followed forum instructions and tightened just to where the noise stopped and locked it in.  Should I back it out just a pinch to alleviate some pressure or leave it?

 

So, the KLX400 cam chain is actually stronger?  Do I need to buy OEM or get a Pro X, etc?

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