426 Engine Noise...


39 replies to this topic
  • creeker

Posted August 08, 2007 - 11:33 AM

#21

Thanks for the info guys, I will check it out asap. Would this key cause the noise to sound as if it is coming from the Left side of the engine around the Valve Cover?

  • Fastest1

Posted August 08, 2007 - 05:35 PM

#22

The actual keyway is on the right, however the counterbalancer itself is on the left. Noises are odd and if you have never checked this on your 2000, do it! It wont take that long and it is cheap to fix if you catch it early. I mean cheap. You can buy a key at a hardware store and file it down or order one from Yamaha.

  • Gerry B

Posted August 08, 2007 - 07:27 PM

#23

when I first had the knocking sound on my bike, it did sound like it was coming from the valve cover. I had a buddy that had the same bike, a 2000 YZ426 and he had the same problem as well. He told me about it and as soon as I took it apart, sure enough it was that little key. It's like a 1.50 piece from yamaha.

  • creeker

Posted August 09, 2007 - 05:11 AM

#24

Cool! Thanks guys!

  • moto2000

Posted August 09, 2007 - 04:06 PM

#25

Setting the ex clearance to .20-.25mm (.0079-.0098) will probably get rid of that tapping noise......:thumbsup:

  • grayracer513

Posted August 09, 2007 - 04:10 PM

#26

Setting the ex clearance to .20-.25mm (.0079-.0098) will probably get rid of that tapping noise......:thumbsup:

It might, but then the exhaust valves would be too tight. The '00 has stainless valves, and calls for .25-.30mm.

  • moto2000

Posted August 09, 2007 - 04:16 PM

#27

Been there done that....

  • creeker

Posted August 25, 2007 - 07:18 PM

#28

Well, installed Wiseco High Comp piston/rings and adjusted the valves and the noise is now gone...

On another note... Bike is 7 years old and has never had piston/rings installed and the stock piston and rings that were removed looked perfect! These bikes are truly bulletproof.

  • maz13b

Posted September 02, 2007 - 07:44 PM

#29

I AM SO GLAD I FOUND THIS THREAD.

I own a 2000 YZ426 and it has a engine knock/rattle.
As described by others its only there at low rpm and once you rev it.. it goes away but sound like somthing is going to break!

I need a bit more info on this fix PLEASE:

-If i pull the clutch cover off where will i see this keyway ?
-Do i need to dismantle the clutch plates or simply remove the clutch cover?

If someone could please explain where abouts this keyway is that would be great! and anything else i should be cautious of?

Ps: I just changed my Piston, rings etc because of this noise i was told by local bike shop it was piston slap. (they measured up Piston and Bore- they were out of spec). so i fitted a PRO-X Big Bore Kit now its a 444cc.. It started first kick with the new piston kit etc BUT when i heard that knocking noise again i was devistated.

Thanks

Cheers
Maz13b

  • maz13b

Posted September 02, 2007 - 08:35 PM

#30

My manual states there is a woodruff key on the left side of the motor behind the Magneto, so this is not on the clutch side?

Is this the same Key?

Also i dont have a rotor holding tool to remove the magneto, is there any other way to remove the magneto safely?

Cheers

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  • grayracer513

Posted September 02, 2007 - 09:59 PM

#31

My manual states there is a woodruff key on the left side of the motor behind the Magneto, so this is not on the clutch side?

Is this the same Key?

No.

If someone could please explain where abouts this keyway is that would be great!

Behind the primary drive gear (item # 9 below). If you find the drive gear nut tight, you don't have a problem with this.

http://parts.yamaha-...ifx?d=32271,2,0

  • maz13b

Posted September 03, 2007 - 04:58 AM

#32

Hi Thanks for the reply.

So the primary drive gear would be the bottom gear where the timing chain connects to.. so il have to pull the magneto off?

Sorry just want to make i check the right thing.

Cheers

  • grayracer513

Posted September 03, 2007 - 06:35 AM

#33

So the primary drive gear would be the bottom gear where the timing chain connects to.. so il have to pull the magneto off?

Sorry just want to make i check the right thing.

Cheers

Uh, no....

The primary drive gear is on the right side, and drives the clutch basket.

  • maz13b

Posted September 03, 2007 - 02:04 PM

#34

Thanks Greyracer, il let you know what i find.

  • maz13b

Posted September 04, 2007 - 03:37 AM

#35

Pulled it all down tonight,

-firstly found my oil filter full of metal shavings.
-all gears seemed in place and not damaged.
-removed the locking washer and bolt on the primary drive gear (bolt was not tight, removed it effortlessly.
-found the keyway key with some deep grooves in it and definately under size, heaps of play in the gear due to the undersized key.

So tomorrow il be off to the shop for some new locking washers, oil filter and a Key.

Questions:

-Does anyone know what size the Key should be or should i just buy an oversized one and file it down as mentioned by others??

-There are another two same size gears to the left of the primary drive gear, they are held on by cerclips, these also have alot of play in them. I pulled one off and saw there is a brass sleeve/collar in the gear- do these need to be replace or should there be play ??


Appreciate the help.

Cheers
Ross

  • grayracer513

Posted September 04, 2007 - 06:04 AM

#36

Try the OEM key; it's cheap. If it feels loose, make one up.

If the play you mention is gear backlash, don't worry about it. If it's from a loose bushing, and you think it's excessive, replace it.

  • maz13b

Posted September 05, 2007 - 02:27 AM

#37

Made up a new key for it tonight, fitted nice and tight with a couple drops of loctite to prevent it from moving hopefully. .

Checked with bike shop today the other gears i mentioned which had play in them are just idler gears and are supposed to have play.

All back together, new oil, oil filter, coolant and she fired perfect.

The rattling noise is totally gone!!!!! wooohoooo

Going out this weekend 3 day trip so will see how she holds up.

Thanks heaps for your help grayrace!

  • Fastest1

Posted September 06, 2007 - 05:15 AM

#38

If you ever do a rebuild, get the crank from a 2001. It has a splined shaft without that key. But it shouldnt give you any more problems for a year or 2.

  • maz13b

Posted September 09, 2007 - 04:05 PM

#39

Yeah thats a good idea, i hope it holds up for a while.

Just took it out over 3 day long weekend and all seemed sweet, no rattling noise.

Big bore kit gave me heaps more bottom end torque, really worth it!

Just need to sort out jetting cause isnt as crisp anymore and play around with sprocket because it runs out of legs.

Any suggestions on both jetting and sprockets?
right now both are stock '00' yz426.

Thanks

  • Fastest1

Posted September 13, 2007 - 05:53 AM

#40

JD's jetting kits available here on TT will help alot!





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