426 valve question


6 replies to this topic
  • skwerlee

Posted October 15, 2007 - 05:17 AM

#1

I play ride a 2000 yz426f and was wondering how to tell if the valves need adjustment. I know you can obviously check them but I'm curious as to what signs to look for that would indicate needing a valve adjustment. I haven't noticed a lack of power at all but I do seem to hear more "clatter" type noises coming from the top end than when I purchased the bike a couple of years ago. Any tips are much appreciated :crazy:

  • grayracer513

Posted October 15, 2007 - 05:59 AM

#2

Check them, obviously.

Noise would be a sign of the valves loosening, but they generally tighten as they wear. What usually happens is that they close up and cause a loss of compression, especially cold, which makes the bike hard to start.

If it's noisy, you might want to check the nut that holds the primary drive and balancer gears on. The early 426 uses a key to locate the balancer gear, and when the nut loosens, the key rattles and the crank gets beat up.

Also, if the bike has never had a timing chain replaced, it needs one, even if only as a precaution.

  • skwerlee

Posted October 16, 2007 - 10:30 AM

#3

If it's noisy, you might want to check the nut that holds the primary drive and balancer gears on. The early 426 uses a key to locate the balancer gear, and when the nut loosens, the key rattles and the crank gets beat up.

Also, if the bike has never had a timing chain replaced, it needs one, even if only as a precaution.


Dang that seems pretty intimidating. I can do simple stuff but I'm no mechanic.

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  • grayracer513

Posted October 16, 2007 - 10:48 AM

#4

It's not that bad if you're reasonably intelligent, careful, and follow the manual, and use the right tools. Maybe someone you know can help.

  • Dustin_Mabro

Posted October 17, 2007 - 06:03 AM

#5

Dang that seems pretty intimidating. I can do simple stuff but I'm no mechanic.


I too have a '00 426 but am far from the weekend warriors that lurk in these threads. I was initially intimidated to simply check the valves on my bike. but after building up my confidence and just doing it i was ready to tackle the cam swap and timing chain. Get yourself a manual, search for the directions on this glorious website and just do it...take your time and you'll do fine :D :crazy:

  • skwerlee

Posted October 17, 2007 - 11:06 AM

#6

I too have a '00 426 but am far from the weekend warriors that lurk in these threads. I was initially intimidated to simply check the valves on my bike. but after building up my confidence and just doing it i was ready to tackle the cam swap and timing chain. Get yourself a manual, search for the directions on this glorious website and just do it...take your time and you'll do fine :D :crazy:


I have a service manual already. I'll have to have my buddy come over and help with some stuff...he wrenches on his 250f all the time.

  • grayracer513

Posted October 17, 2007 - 12:29 PM

#7

I have a service manual already. I'll have to have my buddy come over and help with some stuff...he wrenches on his 250f all the time.

This may help:

http://www.thumperta...405#post3150405





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