Engine Noise, (not cam chain) Options

[Gazlay43]

We picked up an 04 z400 for my girlfriend a few weeks ago. When we got it it had a little noise coming from the engine so I figured it was the cam chain. I put in a new cam chain and mcct and the noise is still there. The noise seems to be coming from somewhere in the lower end like from the cylinder or lower. It has good compression, the valves r good, and it runs great, but the noise really bothers me. I don't want to tear into the motor since I have no idea what the noise is and I dont wanna replace things that aren't necessary. What else should I check? Could it be something in the stator?
Any help is appreciated!

This post has been edited by Gazlay43: Nov 3 2009, 01:44 PM

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[zophar]

Do an oil change and inspect the magnet on the plug and look for metal filings. If there are big pieces the crank/rod bearings are probably going out.

[Gazlay43]

changed the oil right when i got it home. I cut apart the old oil filter and there was some tiny metal bits but it looked like clutch plate particles. No large metal shavings. Is there a way i could check the bearings without splitting the case?

[Danno]

You can check your crank without splitting cases, but you do have to remove the whole top end, nothing horribly serious if you've worked on these engines, there pretty bread & butter, either than that all you need are the gaskets to put it back together. a mechanic shouldnt charge you to much if you can get it as bare as you can on your own

This post has been edited by Danno: Nov 3 2009, 06:06 PM

[Joshz400_03]

Are you sure the mcct is adjusted correctly? The z motor is somewhat noisy

[vinny73]

You can check your crank without splitting cases, but you do have to remove the whole top end, nothing horribly serious if you've worked on these engines, there pretty bread & butter, either than that all you need are the gaskets to put it back together. a mechanic shouldnt charge you to much if you can get it as bare as you can on your own

I have mine torn down right now. What do you look for on the or about the crank to know something is wrong? just caught the piston rubbing the cylinder so I stopped it and tore it apart before I totally f'd it up. Gotta hone the cylinder and see how it looks after that but saw the thread and thought I would ask some related questions.

Does the bronze bushing in the top of the rod ever get replaced. Used to seeing a roller bearing up there!
How do you know if it , the bronze bushing,is due for a replacement?
My bike is an 03 so I figured it was time for a full bearing replacement anyways.
What kind of lateral movement should you have ? I am speaking of the rod in realation to the crank .
and of course, how do you know if your bearings or crank are shot?

Thanks, sorry to hijack! hopefully you may have a few of the same questions. Vinny

This post has been edited by vinny73: Nov 3 2009, 06:28 PM

[vinny73]

Are you sure the mcct is adjusted correctly? The z motor is somewhat noisy

Sorry, but, MCCT? What does that stand for?

[Gazlay43]

im very familiar with these engines. I have an ltr and my sister has a kfx400. I've had both apart down to the frame. The mcct is adjusted correctly. My sisters 400 is nowhere near as noisy as my girlfriends 400. Its nice to have two of the same bikes to use for comparison. We have a planned trip to dumont next week so I guess I'll tear into it when we get back.

This post has been edited by Gazlay43: Nov 3 2009, 06:31 PM

[Gazlay43]

Sorry, but, MCCT? What does that stand for?

manual cam chain tensioner

[vinny73]

manual cam chain tensioner

Gotcha. Thank you.

[jtk]

How about this maybe?

http://suzuki.theatvchannel.com/invision/i...showtopic=42986

[zophar]

You can try turning the crank back and forth with the 17mm nut on the flywheel and listen for it clicking or knocking as you rock back and forth. That will only work if its together.

if its apart try pulling and pushing up and down on the rod and see if it has slack. some rocking slack is common, but if it has push or pull slack you'll hear a click and it means your rod bearing is shot.

also if it is still in the lower half on the engine see how free it rotates. If you can use a finger in the wrist pin hole and make the crank do a full revolution fairly easy then the crank bearings are worn.

In my case the rod and crank bearings were shot. I just got it together on the bottom end last night and man can you tell the difference in new bearings.

[Gazlay43]

was yours making noise?

[Danno]

When i blew my bike sky high, what gave away the crank being tuked was when we rolled it over with a ratchet off the crank, it would knock when the pressure came from a down stroke, that was with the motor still relatively in one piece so i dont want to tell you it will work, that and my bike was blown up also, but yes it can knock when the bearings are shot, id imagine it can be confuse with other noises pretty easy, thats why i find it easier to do by hand.


Thats just my opinion though, im guessing your bearings arent as bad as mine were after running with a split oil pump gear

[Gazlay43]

Well we were planning on taking it to dumont, but now i'm scared that it will seize. What do u think?

[Camaro1976]

use a mechanics stethoscope. or if your cheap use a piece of hose. that will tell you where about its coming from

[Gazlay43]

ya we used a stethoscope on it but the noise resonates throughout the motor
were gonna bring it to dumont and if it seizes up, we have other quads she can ride.
We're gonna tear it apart after this trip blown up or not