Yz 426 valves


11 replies to this topic
  • nugie

Posted August 21, 2010 - 12:45 PM

#1

I just put a hot cams 450 ex cam in my 02 426. Running great just wanted to check my valve clearence. What should everything be?

  • grayracer513

Posted August 21, 2010 - 02:23 PM

#2

Intakes: .10-.15mm
Exhausts: .20-25mm

  • nugie

Posted August 21, 2010 - 04:20 PM

#3

Thanks Grey, So I just slide the feeler gauge in between the lobe of the cam and the top of the lifter to check for clearance correct ?

  • Ryan426

Posted August 21, 2010 - 04:30 PM

#4

make sure your at tdc.

  • brentn

Posted August 21, 2010 - 06:50 PM

#5

One thing I got confused with when checking valves is how much resistance the feeler gauge should have when you slide it in and out underneath the lobe..
Would it be best to shim the valve so that the feeler gauge will not fit, then move one size down at a time until it just slides in but has resistance???

New to this, thanks for your patience.

  • grayracer513

Posted August 21, 2010 - 08:03 PM

#6

The gauge that just fits with a light drag is the correct size. You can wedge a gauge in that's bigger than the actual clearance and lift the valve off its seat a little.

Try the right side lobes that you can actually see first to get the idea.

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  • jecole360

Posted August 22, 2010 - 04:58 PM

#7

Can you give me some info or a link for those cams? Does that bump it up to a 450?

  • xr650r2000

Posted August 22, 2010 - 05:11 PM

#8

The gauge that just fits with a light drag is the correct size. You can wedge a gauge in that's bigger than the actual clearance and lift the valve off its seat a little.

Try the right side lobes that you can actually see first to get the idea.


+1 their should be a light drag on the feeler gauge

  • nugie

Posted August 22, 2010 - 05:12 PM

#9

No it does not bump it up to a 450, The mod is simply done to delete the annoying start procedure of having to use the decomp

  • Ryan426

Posted August 22, 2010 - 05:53 PM

#10

Can you give me some info or a link for those cams? Does that bump it up to a 450?


No, the 450 cam does not make a 426 a 450:lol: All it does is take away the manual decomp.

  • nugie

Posted August 23, 2010 - 06:34 AM

#11

Alright guys my clearance is suppose to be .20-.25mm on the exhaust . I have .356mm clearance on each with a 2.20 shim on 1 and a 2.25 on the other.What shims do I have to replace these ones with ?

  • grayracer513

Posted August 23, 2010 - 09:19 AM

#12

.356 measured minus .25 desired max equals .106
.356 measured minus .20 desired max equals .156

Adding .106 to the existing 2.20 shim yields 2.306 new minimum shim size
Adding .156 to the existing 2.20 shim yields 2.356 new maximum shim size

You do the other one.





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