2002 YZF426 valve clearance


7 replies to this topic
  • Gavindobson1

Posted January 18, 2010 - 05:41 AM

#1

Hi,

Anybody know the correct valve clearance for the 2002 YZF426, I only have the manual for the 2000 model and I am led to believe the tolerance's are different.

Also is their a trick for torquing up the cam caps without dropping the engine.

Thanks.

  • grayracer513

Posted January 18, 2010 - 09:31 AM

#2

They are. The '01-'02 used titanium valves, and the clearances are tighter for the exhausts:

Intake: .10-.15mm
Exhaust: .20-.25mm

You needn't be without the right manual, either:

http://www.yamaha-mo...ice/manuals.jsp

  • Gavindobson1

Posted January 18, 2010 - 04:30 PM

#3

My valves are:

EX: all 0.20mm
IN: all 0.10mm

Which makes me think my clearances are in tolerance howether after speaking to a couple of MX shops, i am told they are all too tight. All advice welcome, please help.

Thanks again

  • tek_01

Posted January 18, 2010 - 04:37 PM

#4

They are on the limit. You will either have to adjust them now or very soon taking into considerations your measurements are 100% spot on

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  • rexbond007

Posted January 18, 2010 - 04:42 PM

#5

they are in spec leave them and check every 20 hrs or when it gets hard to start.

MY 2 cents

  • Gavindobson1

Posted January 18, 2010 - 04:49 PM

#6

Thanks. Think i will adjust them now then as I'm going to be installing my new hot cams ex cam.

Also is their a trick for torquing up the cam caps without dropping the engine.

  • tek_01

Posted January 18, 2010 - 06:52 PM

#7

I dont understand what you mean by doing them up without dropping the engine? Do you mean is there a way to tighten the cam caps without pulling the engine out of the frame? yes of course.. and i should think everyone does it like that. Just take the top engine mount off and anything else that is in the way off and undo the top cover

Too easy of a question thats why im confused :/

  • grayracer513

Posted January 18, 2010 - 10:47 PM

#8

The valve clearances are perfect. The tight edge of the spec is where you want them set, and it's where they were set originally. They'll stay that way for hundreds of hours if the head is healthy, so there is no reason to change them.

Once you install the new cams, you will necessarily have to reset them anyway, so why do it twice.

The "trick" to torquing the cam caps in the frame is to use a 1/4" torque wrench. In the unlikely event that you get one that's still too large to fit, use an offset torque adapter, like the one below. Mounted to the torque wrench at a 90 degree angle like an L, they require no compensation.

Posted Image





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